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Hidizs ST2 Nebula
- Added by Ianbanz
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smexxy
New Head-Fier
Pros: - Lightweight and simplistic shell design
- Good cable quality
- See-through design for USB-C DAC
- Good fitment
- Carrying/Storage Pouch
- Warm and Bright Tonality
- Detailed vocals
- Impressive Mid-range
- Impressive instrument detail, clarity and separation
- Slightly wide sound staging, impressive imaging and good depth.
- Good mid-bass punch and good rumble sub-bass
- Good cable quality
- See-through design for USB-C DAC
- Good fitment
- Carrying/Storage Pouch
- Warm and Bright Tonality
- Detailed vocals
- Impressive Mid-range
- Impressive instrument detail, clarity and separation
- Slightly wide sound staging, impressive imaging and good depth.
- Good mid-bass punch and good rumble sub-bass
Cons: - Slightly sharp sibilance
- Not have the best fitment
- Cable quality is a bit flimsy
- Limited ear tip selection
- Not have the best fitment
- Cable quality is a bit flimsy
- Limited ear tip selection
Quick Disclaimer: After reviewing 9 IEMs and more audio equipment, I still consider myself as a beginner/casual. I enjoy listening to music, podcasts and occasionally do gaming and as always I did not read or watch any reviews regarding the ST2 Pro Nebula so I am going in blind here.
The gear I am using for this review is just the HiBy R1 DAP(review coming soon) and the music files are downloaded with .flac as the audio format for the best sound quality possible.
Thank you so much to Hidizs for sending the ST2 Pro Nebula to our local community for a review tour! We look forward to working with you and to more reviews in the future!
So let’s begin.

The Hidizs ST2 Pro Nebula is currently on Pre-Sale for 54.99$ and will be priced at 89.99$ once the Pre-sale ends in March 15, 2025; I did not expect the ST2 Pro Nebula to be in this price point due to the fact that the IEMs themselves look a bit more on the budget side in terms of design(yes I should not judge a book by it’s cover but hey this is a personal review :v ) though I can say with great confidence is that this IEM breaks all judgement and is one of those gears that exceeds expectations.

I did mention that the build quality is a bit on the budget side. I can assure you that the quality is not cheap. The IEMs and cable are both super lightweight and do not get in the way of things. The shell of the IEMs are made out of plastic while the faceplate has a metallic badge that has their logo and “H I D I Z S” engraved; these IEMs also come equipped with a Dual Magnetic Circuit Dynamic Drivers. The cable does have a nice braided exterior with a black and purple colorway but it could definitely use a bit more thick and sturdy material; it also comes with a built-in microphone should you need it but the best part about this cable is that it comes with the ES9218AC Pro ESS DAC Chip, I absolutely love the design of the plug since it has a small window which shows the internals and chips while having a red LED indicator once it’s plugged in.
UNBOXING EXPERIENCE

Packaging wise I would say that this is comparable to the TANCHJIM Bunny that was sent over to me for review a few weeks ago but the difference here is that the front packaging of the box has some holographic effect on the texts and logos while showing the design of the ST2 Pro Nebula(this was a bit misleading since the front face shows a clear white design but underneath the box has a sticker that says "transparent black"); the sides of the packaging shows the Type C plug and the window showcasing the internals of the DAC chip(worth flexing it not gonna lie) and lastly, flipping the box over will show the specifications of the ST2 Pro Nebula.
Opening the box, the ST2 Pro Nebula IEMs are neatly placed in a thick foam sheet and lifting the pull tab shows the following:

OVERALL IMPRESSIONS
The ST2 Pro Nebula has a warm and bright tonality. I was honestly impressed with the sound quality that the drivers gave and did not expect the warm tonality. Since I’m using the Hiby R1(review coming soon!) as my go-to music player(I don’t have any devices that have a Type C port :v ) it does have a bit of a sharp sibilance which can get uncomfortable overtime and I find myself lowering the volume of the R1 to make the sibilance tolerable, since th ST2 Pro Nebula is already a bright IEM, pairing it with the R1 which is also a bright DAP is a recipe for a sharp sibilance.
Details on the vocals are present giving it a much more intimate listening experience, though it is not ASMR level but given the fact that these are bright there is a certain level of degree when it becomes shouty or detailed but it all boils down to the recording of the audio and the tuning. This also brings me to the mid-range which is quite impressive, instruments have great detail, good clarity and separation, listening to high energy songs makes it more lively without any form of bleeding or masking.
It has a slightly wide sound staging making it a bit more holographic which is also complimented by the impressive imaging and depth. Although I would not compare it to a cinema level of sound surround, I was still impressed by how the drivers and DAC chip work simultaneously to give a pleasant listening experience.
Lastly and certainly not the least is the bass; quite good. It has a pleasant mid-bass punch with a good amount of attack and decay while the sub-bass has a good amount of rumble but lacks a bit more on texture. Bassheads may or may not like this IEM but I find that this has the right amount of bass and it definitely will not rock your eardrum and cause any fatigue.
Comparing this between the LETSHUOER S08 which is a bit more expensive than the ST2 Pro Nebula, the main difference here is that the S08 is a planar IEM while the ST2 Pro Nebula is a dynamic driver IEM which means that the S08 needs more power to bring out its full potential while the ST2 Pro Nebula doesn’t need more power but rather needs a device that has a Type C port. In terms of sound quality, the S08 has a much smoother sibilance even in high volumes while the ST2 can get shouty and will get uncomfortable overtime. They both are on par with each other in terms of mid-range; sound staging, imaging and depth but when it comes to the bass; dynamic drivers tend to deliver more punch and rumble while planar drivers do not so the ST2 wins this aspect.
Is it a bit of an unfair comparison? A little bit, since Planar and Dynamic Drivers are both different and have their own purposes, I find that this is the best comparison I can give considering the price point. I do have the QoA Mimosa up next for review but only then will I compare the ST2 to the Mimosa on the next review.
Overall the ST2 Pro Nebula by Hidiz is one of those IEMs that again exceed beyond expectations. Do not be fooled by the build quality because the dynamic drivers and DAC chip will give you your money’s worth. Sure some would prefer a more hefty build quality considering that these are priced at 89.99$ after the Pre-sale and I agree on that logic too; personally I do wish that the shell would be molded out of resin and perhaps have more ear tip sizes for better fitment, but nonetheless, these IEMs are fantastic. Would I recommend this set? Definitely. Should you grab it now while it’s on Pre-Sale? YES.
Blup blup 𓆟 and happy listening!
The gear I am using for this review is just the HiBy R1 DAP(review coming soon) and the music files are downloaded with .flac as the audio format for the best sound quality possible.
Thank you so much to Hidizs for sending the ST2 Pro Nebula to our local community for a review tour! We look forward to working with you and to more reviews in the future!
So let’s begin.


The Hidizs ST2 Pro Nebula is currently on Pre-Sale for 54.99$ and will be priced at 89.99$ once the Pre-sale ends in March 15, 2025; I did not expect the ST2 Pro Nebula to be in this price point due to the fact that the IEMs themselves look a bit more on the budget side in terms of design(yes I should not judge a book by it’s cover but hey this is a personal review :v ) though I can say with great confidence is that this IEM breaks all judgement and is one of those gears that exceeds expectations.




I did mention that the build quality is a bit on the budget side. I can assure you that the quality is not cheap. The IEMs and cable are both super lightweight and do not get in the way of things. The shell of the IEMs are made out of plastic while the faceplate has a metallic badge that has their logo and “H I D I Z S” engraved; these IEMs also come equipped with a Dual Magnetic Circuit Dynamic Drivers. The cable does have a nice braided exterior with a black and purple colorway but it could definitely use a bit more thick and sturdy material; it also comes with a built-in microphone should you need it but the best part about this cable is that it comes with the ES9218AC Pro ESS DAC Chip, I absolutely love the design of the plug since it has a small window which shows the internals and chips while having a red LED indicator once it’s plugged in.
UNBOXING EXPERIENCE


Packaging wise I would say that this is comparable to the TANCHJIM Bunny that was sent over to me for review a few weeks ago but the difference here is that the front packaging of the box has some holographic effect on the texts and logos while showing the design of the ST2 Pro Nebula(this was a bit misleading since the front face shows a clear white design but underneath the box has a sticker that says "transparent black"); the sides of the packaging shows the Type C plug and the window showcasing the internals of the DAC chip(worth flexing it not gonna lie) and lastly, flipping the box over will show the specifications of the ST2 Pro Nebula.
Opening the box, the ST2 Pro Nebula IEMs are neatly placed in a thick foam sheet and lifting the pull tab shows the following:

- Leather-like material carrying/storage pouch
- 4 pairs of eartips
- Detachable USB-C DSP 0.78mm 2-Pin
OVERALL IMPRESSIONS
The ST2 Pro Nebula has a warm and bright tonality. I was honestly impressed with the sound quality that the drivers gave and did not expect the warm tonality. Since I’m using the Hiby R1(review coming soon!) as my go-to music player(I don’t have any devices that have a Type C port :v ) it does have a bit of a sharp sibilance which can get uncomfortable overtime and I find myself lowering the volume of the R1 to make the sibilance tolerable, since th ST2 Pro Nebula is already a bright IEM, pairing it with the R1 which is also a bright DAP is a recipe for a sharp sibilance.
Details on the vocals are present giving it a much more intimate listening experience, though it is not ASMR level but given the fact that these are bright there is a certain level of degree when it becomes shouty or detailed but it all boils down to the recording of the audio and the tuning. This also brings me to the mid-range which is quite impressive, instruments have great detail, good clarity and separation, listening to high energy songs makes it more lively without any form of bleeding or masking.
It has a slightly wide sound staging making it a bit more holographic which is also complimented by the impressive imaging and depth. Although I would not compare it to a cinema level of sound surround, I was still impressed by how the drivers and DAC chip work simultaneously to give a pleasant listening experience.
Lastly and certainly not the least is the bass; quite good. It has a pleasant mid-bass punch with a good amount of attack and decay while the sub-bass has a good amount of rumble but lacks a bit more on texture. Bassheads may or may not like this IEM but I find that this has the right amount of bass and it definitely will not rock your eardrum and cause any fatigue.
Comparing this between the LETSHUOER S08 which is a bit more expensive than the ST2 Pro Nebula, the main difference here is that the S08 is a planar IEM while the ST2 Pro Nebula is a dynamic driver IEM which means that the S08 needs more power to bring out its full potential while the ST2 Pro Nebula doesn’t need more power but rather needs a device that has a Type C port. In terms of sound quality, the S08 has a much smoother sibilance even in high volumes while the ST2 can get shouty and will get uncomfortable overtime. They both are on par with each other in terms of mid-range; sound staging, imaging and depth but when it comes to the bass; dynamic drivers tend to deliver more punch and rumble while planar drivers do not so the ST2 wins this aspect.
Is it a bit of an unfair comparison? A little bit, since Planar and Dynamic Drivers are both different and have their own purposes, I find that this is the best comparison I can give considering the price point. I do have the QoA Mimosa up next for review but only then will I compare the ST2 to the Mimosa on the next review.
Overall the ST2 Pro Nebula by Hidiz is one of those IEMs that again exceed beyond expectations. Do not be fooled by the build quality because the dynamic drivers and DAC chip will give you your money’s worth. Sure some would prefer a more hefty build quality considering that these are priced at 89.99$ after the Pre-sale and I agree on that logic too; personally I do wish that the shell would be molded out of resin and perhaps have more ear tip sizes for better fitment, but nonetheless, these IEMs are fantastic. Would I recommend this set? Definitely. Should you grab it now while it’s on Pre-Sale? YES.
Blup blup 𓆟 and happy listening!
Ianbanz
New Head-Fier
Pros: Innovative DAC Cable: The ES9281AC PRO-powered cable delivers excellent audio performance while doubling as a portable DAC.
Impressive Sound Tuning: A slightly tweaked Harman curve offers a fun, engaging, and versatile sound profile.
VR Gaming Star: Excels in spatial audio and imaging, creating an immersive gaming experience.
Ultra-Portability: Combines the convenience of a dongle and IEM cable into a compact, lightweight package.
Impressive Sound Tuning: A slightly tweaked Harman curve offers a fun, engaging, and versatile sound profile.
VR Gaming Star: Excels in spatial audio and imaging, creating an immersive gaming experience.
Ultra-Portability: Combines the convenience of a dongle and IEM cable into a compact, lightweight package.
Cons: Midbass Decay: Slightly loose midbass can bleed into the lower mids, adding warmth but reducing precision.
Midrange Detailing: Mids feel slightly recessed and lack layering or microdetail for analytical listening.
Midrange Detailing: Mids feel slightly recessed and lack layering or microdetail for analytical listening.

The Hidizs ST2 PRO Nebula is a bold step forward in the IEM space, blending the simplicity of a single dynamic driver with the power of a high-performance DAC cable. At first glance, it may look like just another Type-C IEM package, but a closer look reveals a game-changing feature: the cable itself doubles as a fully-fledged DAC. Powered by the ES9281AC PRO chip (found in a full sized dac devices like the Astell&Kern AK-HB1 and Fiio KA1), the ST2 PRO delivers an impressive 70mW of power, proving that big things do come in small packages, and i do believe this is the next innovative step to the ultra portable setup.
Whats in the box? here is a quick unboxing video:
Here’s what you get:
ST2 PRO IEMs
USB-C DAC Digital 0.78mm 2Pin Earphone Cable
Three pairs of silicone eartips
USB-C to USB-A adapter
Leather Hidizs pouch bag
Warranty card
Product quality certificate



Design & Build Quality
The ST2 PRO Nebula’s design strikes a balance between form and function. The cable showcases an aluminum alloy USB connector, with transparent windows on either side to reveal the internal PCB. A small LED indicator provides real-time feedback on audio sampling rates—red for PCM (44.1-48kHz) and blue for PCM (88.2-384kHz) or native DSD playback.
The in-line controls and splitter are similarly crafted from aluminum alloy for that extra durability. While the earphone connectors are unfortunately plastic, the build overall feels good for the price point.
The cable measures 1.2 meters and is made from high-purity oxygen-free copper wires wrapped in a textile material for enhanced flexibility and durability. It’s soft, lightweight (just 16 grams), and resists microphonics well. However, it does feel a bit delicate—something to consider if you’re rough with your gear.
Color options include a sleek silver-gray and a striking black-blue, both of which complement the minimalistic yet modern aesthetic.

This sound impression is based on using the ST2 Nebula IEM, but I've also paired the cable with various other IEMs, including planar drivers. It’s incredibly impressive how well the cable handles planars, delivering generous volume with plenty of headroom to spare. I’m genuinely impressed with how effectively the ES9281AC PRO chip is implemented here. The level of detail, clarity, and power packed into such a small device is quite surprising.
I’ve tried a lot of DSP cables, but none come close to the performance of the ST2. If there’s a next iteration of this cable, I’d love to see a more premium version with thicker cables and metal connectors—it would make an already impressive product even better.





For some reason, my graph measurements don’t seem to fully reflect the actual sound of the ST2. When measuring the ST2 IEM with the DAC cable, the graph shows a subbass roll-off that’s not present in real listening. Similarly, when using a regular cable, the graph shows a noticeable peak in the upper treble, which isn’t accurate based on what I hear. It’s a reminder that graphs can be helpful, but they don’t always tell the whole story.
Hidizs has tuned the ST2 PRO Nebula to a slightly tweaked Harman curve, creating a sound profile that's fun, engaging, and surprisingly versatile. One area where this tuning truly shines is gaming. For me, the ST2 PRO feels tailor-made for immersive gameplay. Paired with my MetaQuest 2 VR goggles, it delivers exceptional spatial audio performance. The 3D soundscape is impressively detailed, with precise imaging that places every sound exactly where it should be. It wraps you in a fully immersive audio environment, making every gaming session feel incredibly lifelike and engaging.
Bass
The subbass on the ST2 PRO Nebula is generous, it deep and resonates delivering a satisfying rumble that adds depth and weight to tracks, particularly in genres like electronic, hip-hop, or cinematic scores. It’s the kind of subbass that makes you feel the music, not just hear it. The midbass follows up with a punchy, impactful presence, though its slower decay can sometimes bleed into the lower mids. Interestingly, this bass bleed doesn’t detract from the overall experience; instead, it adds warmth and body to the midrange, creating a cohesive and inviting sound signature. This characteristic works especially well for gaming, where impactful and immersive bass can heighten the experience.
Midrange
The midrange is slightly recessed, which might leave vocals and instruments positioned a step back in the mix compared to the bass and treble. Despite this, the mids maintain a natural timbre and tonal accuracy, which helps them feel lifelike and engaging. The clarity is respectable, though the midrange lacks the intricate layering or microdetails that more analytical listeners might crave. However, its smooth and warm presentation makes it well-suited for casual listening, particularly with vocals and acoustic tracks that benefit from its organic tonality.
Treble
The treble performance is a standout feature of the ST2 PRO Nebula. Energetic and well-extended, the highs bring a sense of air and sparkle to the overall sound signature. This added clarity balances out the warmth from the bass, ensuring that the sound never feels overly dark or congested. The treble's extension also contributes to uncovering fine details in the music, enhancing the perception of resolution across the frequency spectrum. Importantly, it avoids harshness or sibilance, making it suitable for long listening sessions without fatigue. The treble’s liveliness adds refinement and helps tie the entire sound signature together, making it dynamic and engaging for various listening scenarios.
The soundstage is average in width and depth, providing a focused, intimate listening experience rather than an expansive one. Imaging is precise, making it easy to pick out instruments and positions in the mix.
Resolution & Dynamics
For its price, the ST2 PRO Nebula punches above its weight in resolution. It captures subtle details and nuances in listening to music and in gaming, making it a capable performer for music and even in VR gaming. You’ll hear microdetails in recordings and soundscapes that you might miss with lesser gear. Dynamics are equally strong, effortlessly transitioning between quiet and loud passages with ease.

DAC Cable Performance:
The integrated DAC cable is where the ST2 PRO truly shines. Equipped with the ES9281AC PRO chip, the cable delivers enough power to drive even demanding planar IEMs without breaking a sweat. It handles volume adjustments smoothly, with plenty of headroom to spare.
What’s impressive is the level of portability this DAC cable brings. It bridges the gap between traditional USB dongles and standard IEM cables, offering the same performance as many dongles while remaining far more compact. For ultra-mobile audiophile setups this is a game-changer.
While the ST2 PRO Nebula excels in many areas, there’s room for refinement:
Bass Control: The midbass decay could be tighter to avoid occasional bleeding into the mids.
Midrange Detailing: While pleasant, the mids could use more layering and resolution to appeal to analytical listeners.
Build Durability: The lightweight cable, while flexible and comfortable, feels slightly delicate. A thicker, more premium version would be a welcome addition—even at a higher price point.

Final Thoughts:
The Hidizs ST2 PRO Nebula showcases just how far compact audio solutions have come. It’s a versatile IEM that combines great sound with innovative DAC technology, all in a package that’s as portable as it is powerful. Personally, I’d choose this kind of ultra-portable setup over a full-sized USB dongle DAC any day. Plus, I’ve finally found a use for that included Hidizs leather pouch—it’s perfect for carrying this setup around.
For an IEM that delivers stellar sound quality, impressive DAC capabilities, and unmatched portability, the Hidizs ST2 PRO Nebula is a tough contender to beat at its price.
Link: https://www.kickstarter.com/project...efining-hi-res-audio-with-usb-c-dac-earphones
Last edited:
Dhaw
New Head-Fier
Pros: Excellent power available
Balanced V shaped sound profile.
Easy to like clean sound presentation
Good vocals and non fatiguing treble.
Sub bass extension.
Portable and practical
Cable has good feel and does not tangle.
Balanced V shaped sound profile.
Easy to like clean sound presentation
Good vocals and non fatiguing treble.
Sub bass extension.
Portable and practical
Cable has good feel and does not tangle.
Cons: I'd like to see L and R indicated more clearly on the cable rather than embossed on the connector.
IEM could have better bass definition.
Low quality ear tips provided.
IEM could have better bass definition.
Low quality ear tips provided.
The ST2 Pro Nebula IEM has been provided to Audio Reviews Downunder in Australia for ou honest assessment and we thank Hidizs.
Description
The newest release from Hidizs is the ST2 Pro Nebula , featuring a customized 10mm dual magnetic circuit dynamic driver and is supplied with an EES chipped USB C DSP cable (Nebula) which negates the need to use a separate DAC and will plug straight into a phone or PC. It features a powerful DAC and durable 0.78mm 2-pin connector, delivering strong audio and stable signal transmission. With output up to 70 mW+70mW@32Ω.
Thecable is a light two strand twisted cable with fabric covering and suits the purpose, easy to transport and tangle free in my experience. The DSP termination is 10mm small and has a window with power indicator lights. It is supplied with a minimal set of HIDIZS liquid Silicone Ear Tips . The customized pouch provided by HIDIZS isa practical size for such a small cable/IEM combination. TheST2 has smallish moulded resin shells which fit comfortably and can be worn for long listening periods with no problems.
Testing
The ST2 Pro IEM.
I tested this IEM with its dedicated DSP cable and also using three other sources with my own 0.78 cables. The ST2 Pro has a traditional 2 pin socket allowing the use of other cables.
Firstly I tried my HiBy R3 Saber DAP which is good clean neutral source. The ST2 Pro performed well but with very acceptable hi res performance sounding nicely V shaped and clean. . Switching to the Letshuoer DT03DAC which is a fairly powerful $80 DAC and the ST2 warmed up considerably and the bass went to another level with deep sub bass and the vocals gained weight. Next up was the Cayin RU6 my favourite DAC , very technical and with a warmish analogue character. This resulted in a better balanced bass with improved mid bass and some of the boomyness with the other sources was alleviated with the bass sounding more textured and muscular.
The Nebula cable.
The DSP cable can be used with any two pin IEM and I tried it with my Simgot EW300 hybrid and Letshuoer S12 2024 sourcing FLAC files from my HiBy DAP. There was ample power available but with a single ESS chip the sound fell short of the performance from my two dedicated DAC's. But still very acceptable for using as a daily driver combination.
So how does the DSP cable with the Hidizs IEM perform direct from my Pixel phone ? Surprisingly good. This is how I decided to review the cable and IEM combination because it's probably the way many users will purchase. The EES chipped amplifier gives good clarity, natural vocals and the balance between bass mids and treble is very well rendered. The 70 mw output drives the ST2 Pro with ease and I used considerably lower volume settings than I am used to. The driver Hidizs have used in this IEM seems to be very capable. We seem to have a well tuned competent V shaped sound with good soundstage and non sibilant treble.
The Bass.
Solid and substantial is the immediate impression. Bass drum hits with good authority and snares have good crispness. The bass does lack some texture and has a warm sub bass focus. It does have a degree of boomyness depending on the recording. The bass boost remains at the correct end of the spectrum allowing the vocals and midrange plenty of room and air.
Midrange
The mids and vocals are not recessed or thrust too far forward. The tone is natural with a fair degree of added warmth but the timbre of vocals seems correct and natural. Male voices have good strength and weight and female vocals are well rendered being both expressive and natural sounding.
Treble.
TheST2 Pro has an easy to live with treble with enough extension to sprinkle high frequency details from the tracks without any sibilance. This allows good rendition of details of the recording in a balanced way. The Hidizs has very good technicalities with a pleasing ability to break down the recording. It sounds nice and open with no congestion. The soundstage is average, meaning nicely wide with some height and depth.
Conclusion
Hidizs have done a great job producing this ST2 Pro Nebula combination. The star of the show is the tiny DSP built into the Nebula cable with excellent power and resolution. It has the ability to replace budget dongles and also will power higher priced IEMs. The IEM is also no slouch with a sound quality to surpass many budget models and rival some mid ranged sets.
I'd be quite happy using this DSP setup for daily commuting duty. The sound is that good. It would also be the perfect gift for that special person who deserves some better sound equipment.

Description
The newest release from Hidizs is the ST2 Pro Nebula , featuring a customized 10mm dual magnetic circuit dynamic driver and is supplied with an EES chipped USB C DSP cable (Nebula) which negates the need to use a separate DAC and will plug straight into a phone or PC. It features a powerful DAC and durable 0.78mm 2-pin connector, delivering strong audio and stable signal transmission. With output up to 70 mW+70mW@32Ω.
Thecable is a light two strand twisted cable with fabric covering and suits the purpose, easy to transport and tangle free in my experience. The DSP termination is 10mm small and has a window with power indicator lights. It is supplied with a minimal set of HIDIZS liquid Silicone Ear Tips . The customized pouch provided by HIDIZS isa practical size for such a small cable/IEM combination. TheST2 has smallish moulded resin shells which fit comfortably and can be worn for long listening periods with no problems.

Testing
The ST2 Pro IEM.
I tested this IEM with its dedicated DSP cable and also using three other sources with my own 0.78 cables. The ST2 Pro has a traditional 2 pin socket allowing the use of other cables.
Firstly I tried my HiBy R3 Saber DAP which is good clean neutral source. The ST2 Pro performed well but with very acceptable hi res performance sounding nicely V shaped and clean. . Switching to the Letshuoer DT03DAC which is a fairly powerful $80 DAC and the ST2 warmed up considerably and the bass went to another level with deep sub bass and the vocals gained weight. Next up was the Cayin RU6 my favourite DAC , very technical and with a warmish analogue character. This resulted in a better balanced bass with improved mid bass and some of the boomyness with the other sources was alleviated with the bass sounding more textured and muscular.
The Nebula cable.
The DSP cable can be used with any two pin IEM and I tried it with my Simgot EW300 hybrid and Letshuoer S12 2024 sourcing FLAC files from my HiBy DAP. There was ample power available but with a single ESS chip the sound fell short of the performance from my two dedicated DAC's. But still very acceptable for using as a daily driver combination.
So how does the DSP cable with the Hidizs IEM perform direct from my Pixel phone ? Surprisingly good. This is how I decided to review the cable and IEM combination because it's probably the way many users will purchase. The EES chipped amplifier gives good clarity, natural vocals and the balance between bass mids and treble is very well rendered. The 70 mw output drives the ST2 Pro with ease and I used considerably lower volume settings than I am used to. The driver Hidizs have used in this IEM seems to be very capable. We seem to have a well tuned competent V shaped sound with good soundstage and non sibilant treble.

The Bass.
Solid and substantial is the immediate impression. Bass drum hits with good authority and snares have good crispness. The bass does lack some texture and has a warm sub bass focus. It does have a degree of boomyness depending on the recording. The bass boost remains at the correct end of the spectrum allowing the vocals and midrange plenty of room and air.
Midrange
The mids and vocals are not recessed or thrust too far forward. The tone is natural with a fair degree of added warmth but the timbre of vocals seems correct and natural. Male voices have good strength and weight and female vocals are well rendered being both expressive and natural sounding.
Treble.
TheST2 Pro has an easy to live with treble with enough extension to sprinkle high frequency details from the tracks without any sibilance. This allows good rendition of details of the recording in a balanced way. The Hidizs has very good technicalities with a pleasing ability to break down the recording. It sounds nice and open with no congestion. The soundstage is average, meaning nicely wide with some height and depth.


Conclusion
Hidizs have done a great job producing this ST2 Pro Nebula combination. The star of the show is the tiny DSP built into the Nebula cable with excellent power and resolution. It has the ability to replace budget dongles and also will power higher priced IEMs. The IEM is also no slouch with a sound quality to surpass many budget models and rival some mid ranged sets.
I'd be quite happy using this DSP setup for daily commuting duty. The sound is that good. It would also be the perfect gift for that special person who deserves some better sound equipment.
Zerstorer_GOhren
1000+ Head-Fier
Pros: ● Lightweight yet solidly structured resin shell chassis.
● Finally, with a detachable cable feature as I encountered models from other brands that are usually fixed on the earpieces.
● Comfortable to wear without any discomfort and wear fatigue.
● It has a substantial amount of inclusions inside of its packaging box.
● Flagship-grade USB DAC from ESS.
● Better than average stock cable.
● DSD decoding supports up to DSD128 for serious audiophiles.
● MQA unfolding capability for MQA format lovers.
● A fun and engaging tuning that casual listeners and audio enthusiasts that prefers more coloured tonality
● Impactful and rumbly bass response
● Good for tracking on low octave male vocals like bass and bass-baritone ones as they have that deep resonating voices that this set is able to deliver.
● Almost correct timbre and tonality on bass-clef instruments.
● Warm and smooth midrange presentation.
● An energetic and bright treble presentation.
● Good driver coherency performance.
● Finally, with a detachable cable feature as I encountered models from other brands that are usually fixed on the earpieces.
● Comfortable to wear without any discomfort and wear fatigue.
● It has a substantial amount of inclusions inside of its packaging box.
● Flagship-grade USB DAC from ESS.
● Better than average stock cable.
● DSD decoding supports up to DSD128 for serious audiophiles.
● MQA unfolding capability for MQA format lovers.
● A fun and engaging tuning that casual listeners and audio enthusiasts that prefers more coloured tonality
● Impactful and rumbly bass response
● Good for tracking on low octave male vocals like bass and bass-baritone ones as they have that deep resonating voices that this set is able to deliver.
● Almost correct timbre and tonality on bass-clef instruments.
● Warm and smooth midrange presentation.
● An energetic and bright treble presentation.
● Good driver coherency performance.
Cons: ● Too coloured sounding for uncompromising neutral heads.
● Instances of bass smearing
● Recessed midrange presentation
● Some tonal colour oddities particular on vocals like countertenors and mezzo-sopranos.
● Occurrences of tinny, metallic and a tad piercing sound on its midrange up to treble regions.
● Noticeable limitations on the majority of its technical capabilities
● Not the most resolving in terms of resolution capabilities, the fact that it was a bit brightly-tuned.
● Instances of bass smearing
● Recessed midrange presentation
● Some tonal colour oddities particular on vocals like countertenors and mezzo-sopranos.
● Occurrences of tinny, metallic and a tad piercing sound on its midrange up to treble regions.
● Noticeable limitations on the majority of its technical capabilities
● Not the most resolving in terms of resolution capabilities, the fact that it was a bit brightly-tuned.

Nebulae are enormous clouds composed of gases and dust in the cosmos which were tenuous and diffused in nature and this interstellar phenomena are the results of either newly-formed stars or due to after effects of a supernovae.

HIDIZS is one of the audio companies that releasing some interesting products in the audio market with the likes of S9 PRO, AP80 PRO X and their best product, the MP145 which is considered one of the best or probably still the top-honcho of planar magnetic IEM at under $200/£140. But now we have another intriguing product from them and this one is cost at an affordable price.

This is HIDIZS ST2 PRO NEBULA, this one is quite a unique product that HIDIZS released at the last quarter of 2024 as it doesn't use a standard connector analogue termination plug but rather a newer form of connectivity which is now a norm to all devices, The USB Type-C. And it has single driver configuration on its ear pieces that the majority of current entry-level sets in the audio market have this kind of driver set-up.

The ST2 PRO NEBULA uses a 10mm dual magnetic chambered dynamic driver with a composite diaphragm consisting of PU (Polyurethane) and PEEK (Polyether Ether Ketone) which are both thermoplastic but offer different properties. With the flexibility and rigidity of a PU along with the low density and high mechanical strength of the PEEK, it gives a diaphragm even more responsive and less distortion to deliver a high resolution sound , a broader response range with deeper bass, clear mids and detailed highs.

The driver then encapsulated in an imported hypoallergenic resin shell structure that was ergonomically-designed that ensures good fitting and comfortable wear for longer listening sessions. It utilises a proven 0.78mm bi-pin connector as its interlocking mechanism, in which you replace the stock cable with a standard one with analogue termination plug.





Regarding its wearability, as I mentioned a while ago that the outline of its shell structure was meticulously designed to be ergonomic to all ear sizes, and it rests well into my Asian-size lugholes without any discomfort. It offers an excellent passive noise isolation that is able to block some unwanted external noises from the outside surroundings.

As for its stock cable, this one is rather a rarity among other IEMs as it doesn't use the analogue termination plug like 3.5mm single-ended or 4.4mm balanced but rather a USB type-C which is the standard of all modern devices. The USB-C itself has a Hi-Fi DAC chip which is a proven flagship SOC model from ESS, the ES9281AC PRO which is also used on other Hi-Fi devices like Questyle M15s, Audirect Team 1 amplifier and A&K AH HB1. This audio chip is a high performance USB DAC which has 32-bit with 2-channels with a proprietary SABRE headphone amp that ensures high quality faithfully reproduced sound quality.


The overall structure of the cable is a 2-core high purity oxygen-free copper and it was coated with a fabric-like insulator. It also has in-line control and a high definition microphone to receive calls or transmitting voice over messages in video gaming.

This one also has a LED light to determine sample rate status. Here are some information of its colour coding modes:


RED: PCM 44.1 - 48kHz
BLUE: PCM 88.2 -384kHz & DSD 64-128
On its product packaging, while it was packed in a square packaging box, like a usual HIDIZS product, it was well-accessorised as it was furnished with quantifying amounts of inclusions inside.

Here are the following contents that we could find inside of its packaging box:
- Pair of ST2 PRO IEM transducers
- Stock cable
- Three (3) of balanced bore silicone ear tips in different standard sizes.
- USB-C to USB-A Adapter
- Leatherette carrying pouch
- Paperwork like warranty card and Q.C. stub



Since this is based on the performance of the audio chip with a support of DSP decoding, this DAC IC will simply decode and transmit audio transmission with zero latency, enough to deliver an almost accurate audio reproduction with a full-range frequency response. This one is universally compatible with most known modern devices like Android phones, iPhones (the ones with USB type-C), PC, iMacs, tablets and laptops.

In terms of software support, This one is universally compatible with major operating systems either in mobile or desktop options like Android, iOS, Windows, MacOS, Linux and Harmony OS. This one can deliver a total of 70 mW + 70mW at 32 ohms of audio signal output.
When it comes to tonal profile, this set has a V-shaped sound signature in a stock tuning format. This one is quite coloured sounding as it has more elevation on low and high frequencies on its overall sound.

LOWS/BASS:
The initial impression that I noticed is that it has a noticeable sub-bass presence on its overall bass quality but the mid bass appears to have an adequate texture which is crucial to the tonal colour of certain bass-centric instruments and low octave male vocals. In general, it delivers a punchy, impactful and rumbly bass response albeit there are some instances of bass bleed that smudge across the lower midrange.
As I perceivably felt the reverberations and rumble that were generated from sub bass-focused instruments like drum machines, synthesisers and double basses, its mid bass texture is enough to give a substantial note weight on bass-clef instruments and deep male vocals. Bass guitars have weight and sombre sound while double-basses have that broadness with raspiness of its sound and bass kick drums sound full and sonorous on every stroke. As for male vocals, basses have dense and reverberant voices while bass-baritones have a plush and a bit dusky sound from their vocals.
MIDRANGE:
The midrange presentation of this one is definitely in a scooped state in which I noticed that some vocals and instruments are quite behind of its overall sound. But it doesn't sound lean as it has a warm to add more density on a certain note weight on instruments and vocals but there some caveats in which I also noticed that it sounds bit veiled (soft or too smooth) and less detailed in some tracks even this one is tuned to have a bit energetically-tuned midrange.
On male vocals, baritones sound warm and smooth while tenors have brassy with a hint of metallic sound, and countertenors have a fiery and “coppery” sound with a bit of spiciness. As for female vocals, contraltos have strong and husky sound from their chesty vocals, mezzo-sopranos have a fiery sound on their vocals but sometimes it sounds too velvety in my liking particularly on Andrea Corr’s vocals. And then sopranos, they have these silky and gleaming sounds on their vocals which somewhat make them a bit of an all rounder for all sopranos types but on a less refined side.
When it comes to instruments, on strings, guitars sound a bit crisp and a tad bright on every plucking on its note strings, violins have these sweet and sensuous sounds of every bowstroke, and cellos sound sonorous and cantabile. The woodwind instruments like concert flutes, piccolos, clarinets and saxophones, concert flutes sound mellow and brilliant, piccolos sound light and intense, clarinets have mellow and melodic sound, and saxophones have that brilliant and expressive sound. As for brasses like trumpets, trombones and horns, they sound brilliant, sinister and full respectively. Then the percussive ones, snares have a hard and a bit boomy sound, tom-toms have warm and resonant sound, field drums sound a bit boomy and sombre, and the last one, kettledrums have this deep and resonant sound on every stroke. The pianos appear to have a balanced tone as it sounds sweet, warm and full.
HIGHS/TREBLE:
The treble response of this one is quite bright with some shimmer and energy as it gives that sense of crisp and clarity on vocals and instruments, although I noticed that this set has a bit metallic and shrillness on its overall treble sound quality.
For a single dynamic driver, it has a good airy extension with some intensity of its sparkle that certainly affects the tonal colour of some instruments. Cymbals sound bright while the hi-hats have a short sizzling tone on their chick-y sound, celestas have a silvery sound and glockenspiel sound shimmering.
SOUNDSTAGE, IMAGING AND OTHER TECHNICALITIES:
The ST2 PRO NEBULA seems to project just an average-size sound field in which it gives me an intimate head room within my aural perception. It has a middling lateral span on its width, good height reach and an immersive depth.
On its stereo imaging, this one is rather unusual as it has this concave-like stereo presentation in which I was able to pinpoint some of the placements of the vocals and instruments in a perceived sonic spatiality. But my main gripe on this technical aspect was that its layering is quite mediocre but at least, it has decent separation. I’m taking some consideration on recommending this one to do some playback on some complex multi-instrumental genres like orchestra and jazz as this set is somewhat struggling on those genres.
It has an excellent coherency of its driver performance as it was able to perform broad and responsive transients that it was able to deliver a fast bass response and clear sound without any noticeable distortion at all. As for its resolution capability, I still consider it as average despite that emphasis on upper midrange and some parts of the presence section of the treble region as it is less resolving in my opinion. Its micro-detail capability is less capable of extracting some nuances and subtleties from a sonic background from an audio track but at least, it has a solid macro-dynamics in which I can perceive the variety of loudness.
PEER COMPARISONS:
TANCHJIM TANYA DSP
- This one also has a single dynamic driver with a circular metal shell structure but unlike the ST2 PRO, it doesn't have detachable cable but rather it was fixed on the earpieces.
- This is also powered and processed with DSP chip but the said chip only offers a limited sampling rate up to 96kHz in PCM format, native DSD format doesn't have sampling support on this one.
- It can be used on any device with a USB type-C port as long as it supports USB Audio.
- It is universally supported across major OSes either its a mobile or desktop one.
- The tonal profile of this one has a U-shaped sound signature which aligns with a Harman-ish type of sound as it has rumbly and tighter bass response, a bit recesses yet more balanced midrange presentation with enough treble energy.
- It has very similar technical capabilities with the ST2 PRO from soundstage size up to the resolution capabilities.
- This one is way cheaper than ST2 PRO.
HIBY XENO
- While this one is in the same category with ST2 PRO, it has a rather unusual driver configuration and also an implementation of audio chips as this one has MEMS driver aside from dynamic driver although it has a non-detachable cable on its peculiarly designed 3D-moulded resin shell.
- Another unique implementation of this unit was its dual DAC set-up of different brands and models in which work in tandem to decode high resolution audio at high sample rate.
- It has a control console for play/pause, volume control and tonal presets.
- XENO universally supports major OSes in the market from Android OS up to MacOS.
- Since it has 3 tonal presets, Flat mode has a balanced-neutral sound while the Dynamic mode has a more coloured, U-shaped sound profile, and then the Gaming/Cinematic mode has a more V-shaped sound profile.
- Depends on the tonal presets, but the Gaming/Cinematic mode has the widest perceived soundstage and it is quite more resolving among them.
As the current state of today’s current technology as we are now veering towards wireless connectivity that most modern devices like smartphones are now dropping the final vestiges of analogue technology that traces back from the late 19th century, the 3.5mm headphone jack. And now only the USB type-C ports are now the only viable option as wireless audio capability is still inferior compared to the wired, analogue audio. Given how adaptive the HIDIZS is in the current audio market as they continue to be as innovative as they can and the ST2 PRO is the result of their research and development.
With a plug and play as its main core of the product along with the implementation of an old flagship USB DAC chip that works as it main DSP to deliver a good sound quality, this will be a good option for both audio enthusiasts and also for casual users as operating this device will be beneficial for them to use.
HIDIZS ST2 PRO NEBULA is now available at HIDIZS' official store and also you can support them on the kickstarter campaign for this device. (Non-affiliated links guaranteed)
OFFICIAL STORE:
https://www.hidizs.net/products/hid...mance-dac-usb-c-hifi-digital-in-ear-earphones
KICKSTARTER:
https://www.kickstarter.com/projects/hidizs/st2-nebula-redefining-hi-res-audio-with-usb-c-dac-earphones

SPECIFICATION:
MODEL: HIDIZS ST2 PRO
IMPEDANCE: 32Ω
SENSITIVITY: 108dB
FREQUENCY RESPONSE: 20Hz – 40KHz
CABLE LENGTH: 1.2m
PIN TYPE: 0.78 2-PIN CONNECTOR
PLUG TYPE: 3.5mm
DRIVER UNIT(S): (1) DYNAMIC DRIVER
TESTING TRACKS: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)
Alison Krauss -When You Say Nothing At All *
Jade Wiedlin - Blue Kiss**
Led Zeppelin - When The Levee Breaks **
Mountain - Mississippi Queen *
Queen - Killer Queen **
Guns N' Roses - Patience *'*
Eric Clapton - Tears in Heaven '*'
Sergio Mendes- Never Gonna Let You Go '*'
Pearl Jam - Daughter **
Roselia - Hidamari Rhodonite *
Assassin - Fight (To Stop The Tyranny)*
Celtic Frost- Visual Aggression *
New Order - Blue Monday *
The Corrs- What Can I do (unplugged version) *
Jimi Hendrix Experience - Voodoo Child *
The Madness- Buggy Trousers *
Metallica - Motorbreath **
Mariah Carey- Always Be My Baby *
Destiny's Child - Say My Name *
Malice Mizer- Au Revoir *
Mozart - Lacrimosa *
New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *
Eva Cassidy - Fields of Gold (Sting cover)*
Michael Jackson - Give In To Me *
Exciter - Violence and Force *
Diana Krall - Stop This World **
Debbie Gibson - Foolish Beat *'*
The Sisters of Mercy – Lucretia My Reflection**
Suzanne Vega – Luka **
Lauren Christy – Steep *
Ottoman Mehter - Hucum Marsi *
Diana Damrau - Mozart: Die Zauberflöte*
P.S.
I am not affiliated to HIDIZS nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.
Once again, I would like to send my gratitude to BELLA JUAN for providing this review unit. I truly appreciate their generosity and trust towards me and other reviewers.




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VLAYAR
New Head-Fier
Pros: 2 in 1 (IEMs + DAC)
Sound of IEMs
Sound of DAC
Build
Cool concept for the price
Sound of IEMs
Sound of DAC
Build
Cool concept for the price
Cons: IEMs for basshead

Picture this: you’re standing in the middle of an audio store, torn between grabbing a pair of bass-pounding IEMs or a sleek DAC cable to up your streaming game. You sigh, because why can’t life be simpler? Well, Hidizs heard your inner monologue and said, “Hold my soldering iron.” Enter the Hidizs ST2 Pro, the audio lovechild of innovation and practicality, giving you two devices in one tidy package.
This isn’t just a pair of IEMs or just a DAC cable. It’s a Jack-of-All-Trades, Master-of-Most kind of deal. Let’s unpack this marvel and see why it deserves a permanent spot in your audio arsenal.

Tech Specs
IEMs:
- Driver Type: Dual dynamic drivers
- Frequency Response: 20Hz - 40kHz (yes, bats can groove to it too)
- Impedance: 18 ohms
- Sensitivity: 110dB/mW
- Tuning: Bassy. Like, “did the ground just shake?” bassy.
- Chipset: ESS9281C Pro (fancy, right?)
- Decoding: PCM up to 32-bit/384kHz, DSD128, and MQA
- Output Power: 2Vrms balanced, 1Vrms unbalanced
- Compatibility: Works with everything short of your toaster—Windows, macOS, Android, and iOS (yes, even your grumpy old phone).

Bass: Earthquake Mode Activated
The ST2 Pro IEMs aren’t here to whisper sweet nothings in your ears—they’re here to rumble, stomp, and make your playlist feel alive. Bassheads will be thrilled with the punchy low-end, which doesn’t just hit—it slaps. The mids are slightly recessed, making it perfect for bass-heavy genres, while the treble adds just enough sparkle to remind you it exists.
If you’re into electronic, hip-hop, or anything with a drop, the ST2 Pro IEMs will make you feel like you’re front and center at the gig. Just don’t blame them when your coworker complains about you foot-tapping through meetings.

DAC Cable: The Smooth Operator
Now let’s talk about the cable, which isn’t just an accessory—it’s a full-fledged DAC, complete with MQA decoding for all you Tidal fans out there. Plug it into your phone, laptop, or tablet, and suddenly, your audio sounds like it’s been upgraded from an AM radio to a high-end studio.
The sound profile is neutral and detailed, giving you clarity and separation that’ll have you rediscovering your favorite tracks. It’s perfect for pairing with other IEMs or headphones when you want to dial down the bass and go for a more balanced experience. Think of it as the “calm after the storm” when the IEMs have had their fun.

Swapping: Your Ticket to Audio Freedom
Here’s the magic trick: swap out the IEMs for a different pair, and the DAC cable adapts like a chameleon. Suddenly, you’ve gone from basshead mania to reference-level neutrality without needing an entirely new setup. Whether you’re in the mood for booming lows, sparkling highs, or something in between, this combo lets you experiment without emptying your wallet.

Why It’s a Steal
Let’s face it: the audio world isn’t known for being wallet-friendly. Yet, Hidizs ST2 Pro feels like an exception to the rule. For the price of a nice dinner (or two mediocre ones), you’re getting:
- A solid pair of IEMs that could easily stand on their own.
- A high-quality DAC cable that doesn’t just sound great—it transforms your entire setup.
- The ability to mix, match, and play audio scientist with your sound signature.

Conclusion
Hidizs ST2 Pro isn’t just a product—it’s a concept, a rebellion against overpriced audio gear that makes you choose between functionality and fun. With this dynamic duo, you don’t have to pick. You get bass, clarity, and versatility in one clever package.
For anyone looking for an affordable way to experiment with sound, or simply enjoy the best of both worlds, the ST2 Pro is a must-have. Highly recommended for the adventurous and budget-conscious alike!

Kickstarter Link:

https://www.kickstarter.com/project...res-audio-with-usb-c-dac-earphones?ref=71o7oz
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Ichos
Reviewer at hxosplus
Pros: + Available with or without earphones
+ The cable is neutral sounding with good technicalities
+ Powerful for the size
+ Low power consumption
+ In-line controls and microphone
+ 2-pin and MMCX versions
+ 32bit/384kHz PCM, DSD128 and 8X MQA
+ Soft and well made cable
+ LED indicator in the plug
+ Affordable
+ The earphones have plenty of bass that is not overwhelming
+ Decent tonal balance
+ They are lightweight and comfortable
+ Well made and affordable
+ The cable is neutral sounding with good technicalities
+ Powerful for the size
+ Low power consumption
+ In-line controls and microphone
+ 2-pin and MMCX versions
+ 32bit/384kHz PCM, DSD128 and 8X MQA
+ Soft and well made cable
+ LED indicator in the plug
+ Affordable
+ The earphones have plenty of bass that is not overwhelming
+ Decent tonal balance
+ They are lightweight and comfortable
+ Well made and affordable
Cons: - Regular prices are not yet determined
- The cable looks a bit fragile
- You can't control the volume
- No DSP features
- The earphones are only suitable for casual listening
- Average technicalities and resolution
- Way too colored tuning
- The cable looks a bit fragile
- You can't control the volume
- No DSP features
- The earphones are only suitable for casual listening
- Average technicalities and resolution
- Way too colored tuning
(The rating is for the cable alone)
Hidizs is a reputable audio brand recognized for producing high-quality earphones and USB DACs that offer an impressive price-to-performance ratio while remaining affordable. Notable products such as the MP143 and the S8 Pro Plus have garnered significant acclaim within the audiophile community.
Hidizs ST2 Pro Nebula USB type-C cable
Hidizs has recently introduced the ST2 Pro Nebula, a USB Type-C cable that can be purchased either as part of an earphone bundle or separately in 2-pin and MMCX versions. Initially, the ST2 Pro will be available on Kickstarter, followed by general retail availability.
The Hidizs ST2 Pro Nebula is an earphone cable featuring a Type-C connector along with 2-pin or MMCX plugs. It incorporates the ESS ES9281AC PRO DAC/amp chip, which is capable of handling sampling rates up to 32bit/384kHz PCM, DSD128, and 8X MQA unfolding. The ST2 Pro has a power output of 70mW*2/32Ω and operates with a remarkably low power consumption that I measured as just 0.05A, ensuring high efficiency.
This cable is compatible with a variety of devices, including Android, iOS, and any USB Type-C-enabled systems such as Windows PCs or Macs. The wired nature of the connection guarantees zero latency, making it ideal for gaming and watching movies.
Additionally, the ST2 Pro features a convenient in-line control button equipped with an HD microphone for phone calls. Users can utilize the button to answer or end calls and manage music playback (one click for play/pause and double click for the next track), although volume adjustment is not supported.
Design and build quality
The cable is equipped with an aluminum alloy USB connector that features transparent windows on both sides, allowing visibility of the internal PCB. An LED indicator for sampling rates illuminates red for PCM decoding at 44.1-48kHz and blue for PCM rates ranging from 88.2-384kHz or for native DSD playback. While the in-line control and splitter are constructed from aluminum alloy, the earphone connectors are made of plastic. The USB connector may become slightly warm during use, but it does not reach excessive temperatures.
Measuring 1.2 meters in length, the cable incorporates high-purity, oxygen-free copper wires, which are tightly encased in a woven textile material to enhance durability and flexibility. This cable is well-constructed, being soft and lightweight at 16 grams, and it produces minimal microphonic noise, although it may appear somewhat delicate. The ST2 Pro is offered in silver-gray or black-blue color options.
The bundled earphones
The Hidizs ST2 Pro Nebula earphones are equipped with a specially designed 10mm high-performance dual magnetic circuit dynamic driver, featuring a PU+PEEK composite diaphragm. These earphones are calibrated according to the H-2019 target curve. The ear-shells are constructed from a skin-friendly resin compound, complemented by aluminum alloy faceplates that prominently display the Hidizs logo.
Designed with ergonomics in mind, the ear-shells boast a custom-like fit and a lightweight design (7g each), ensuring a comfortable and stress-free listening experience while providing effective passive noise isolation. The earphones are offered in both semi-transparent black and fully transparent variants.
Accessories
The ST2 Pro Nebula comes with a handy carrying pouch and a USB type-C to A adapter plus three sets of silicone ear-tips for the version with the earphones.
Audio stuff - Cable alone
The ST2 Pro cable possesses sufficient power to effectively drive sensitive earphones, such as the Hidizs MP143 or the Dunu Kima 2, which I utilized during my assessment.
This cable features a neutral and balanced sound signature, enhanced by a slight touch of brightness. It is capable of delivering exceptional performance for all entry-level earphones and serves as an excellent alternative to portable USB DAC dongles, offering a more compact and lightweight solution while consuming significantly less power.
Equipped with the ES9281AC DAC chip, this cable provides superior sound quality in comparison to the standard codecs found in most similar products. The audio output is characterized by clarity and transparency, featuring deep and impactful bass, a melodious mid-range, and extended treble. The technical performance is commendable for a device of this nature, showcasing controlled low frequencies, well-defined mids, and energetic treble that avoids being overly sharp or harsh.
Although I would not suggest this cable for critical listening or for use with high-end earphones, it represents an excellent option for individuals seeking quality sound on the move without the inconvenience of a USB DAC dongle.
Audio stuff - Cable & bundled earphones
The ST2 Pro earphones, paired with a USB Type-C cable, feature the widely appreciated tuning that aligns with the popular H-2019 target curve. This entry-level earphone set is crafted for on-the-go listening across a variety of musical genres, and its tuning approach can be deemed effective.
The bass response is prominent and robust, showcasing excellent sub-bass extension along with a substantial mid-bass presence. Importantly, it avoids overwhelming the mid-range, maintaining a satisfying physical impact that is likely to resonate with fans of mainstream music. While the texture and resolution are adequate for this category, the tuning prioritizes enjoyment over tonal precision.
In terms of mid-range performance, it is not significantly recessed compared to typical V-shaped tunings, allowing for a clear and present sound with sufficient resolution. Vocals and instruments are rendered in a realistic and harmonious manner, exhibiting satisfactory timbre accuracy. However, the textures may lack refinement, resulting in a sound that feels somewhat flat and less emotionally engaging. Nonetheless, such critiques may be considered somewhat unjust given the earphones' intended purpose and market positioning.
The treble, while somewhat limited in resolution and definition, effectively integrates with the overall sound profile. It offers a lively and extended quality with a hint of brightness, without becoming sharp or fatiguing. The sound remains vibrant, avoiding any dullness, and the timbre does not exhibit excessive artificiality or lack of weight.
Overall, the Hidizs ST2 Pro presents a tuning that is well-suited to its intended use, complemented by satisfactory technical performance. The soundstage is adequately wide and spacious, providing good imaging capabilities. Although it may lack grandeur or depth, it avoids any sense of congestion or claustrophobia.
Conclusion
The Hidizs ST2 Pro Nebula cable is sufficiently well performing to establish its presence in a highly competitive market. This cable serves as an outstanding option for individuals seeking to enjoy their preferred earphones while on the move, without significantly increasing the bulk associated with their smartphone.
Furthermore, for those who do not yet possess a quality pair of earphones or are in search of an additional set, the Hidizs ST2 Pro Nebula cable can be purchased alongside its compatible earphones.
In any case, the Hidizs ST2 Pro delivers very good sound quality and superior craftsmanship at a reasonable price point.
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The review sample was kindly provided free of charge in exchange for an honest review. I don't use affiliate links. The Hidizs ST2 Pro is available through Kickstarter and regular sales will follow.
The prices are ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units) - ST2 PRO Nebula (Early Bird): $49.00 - ST2 PRO Nebula USB-C 2-pin or MMCX earphone cable only (Early Bird): $36.00.
Regular prices will be announced after the Kickstarter campaign ends.
To purchase please use the Kickstarter link.
Disclaimer: For various Google indexing reasons, parts of this review have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
Hidizs is a reputable audio brand recognized for producing high-quality earphones and USB DACs that offer an impressive price-to-performance ratio while remaining affordable. Notable products such as the MP143 and the S8 Pro Plus have garnered significant acclaim within the audiophile community.

Hidizs ST2 Pro Nebula USB type-C cable
Hidizs has recently introduced the ST2 Pro Nebula, a USB Type-C cable that can be purchased either as part of an earphone bundle or separately in 2-pin and MMCX versions. Initially, the ST2 Pro will be available on Kickstarter, followed by general retail availability.
The Hidizs ST2 Pro Nebula is an earphone cable featuring a Type-C connector along with 2-pin or MMCX plugs. It incorporates the ESS ES9281AC PRO DAC/amp chip, which is capable of handling sampling rates up to 32bit/384kHz PCM, DSD128, and 8X MQA unfolding. The ST2 Pro has a power output of 70mW*2/32Ω and operates with a remarkably low power consumption that I measured as just 0.05A, ensuring high efficiency.
This cable is compatible with a variety of devices, including Android, iOS, and any USB Type-C-enabled systems such as Windows PCs or Macs. The wired nature of the connection guarantees zero latency, making it ideal for gaming and watching movies.
Additionally, the ST2 Pro features a convenient in-line control button equipped with an HD microphone for phone calls. Users can utilize the button to answer or end calls and manage music playback (one click for play/pause and double click for the next track), although volume adjustment is not supported.

Design and build quality
The cable is equipped with an aluminum alloy USB connector that features transparent windows on both sides, allowing visibility of the internal PCB. An LED indicator for sampling rates illuminates red for PCM decoding at 44.1-48kHz and blue for PCM rates ranging from 88.2-384kHz or for native DSD playback. While the in-line control and splitter are constructed from aluminum alloy, the earphone connectors are made of plastic. The USB connector may become slightly warm during use, but it does not reach excessive temperatures.
Measuring 1.2 meters in length, the cable incorporates high-purity, oxygen-free copper wires, which are tightly encased in a woven textile material to enhance durability and flexibility. This cable is well-constructed, being soft and lightweight at 16 grams, and it produces minimal microphonic noise, although it may appear somewhat delicate. The ST2 Pro is offered in silver-gray or black-blue color options.

The bundled earphones
The Hidizs ST2 Pro Nebula earphones are equipped with a specially designed 10mm high-performance dual magnetic circuit dynamic driver, featuring a PU+PEEK composite diaphragm. These earphones are calibrated according to the H-2019 target curve. The ear-shells are constructed from a skin-friendly resin compound, complemented by aluminum alloy faceplates that prominently display the Hidizs logo.
Designed with ergonomics in mind, the ear-shells boast a custom-like fit and a lightweight design (7g each), ensuring a comfortable and stress-free listening experience while providing effective passive noise isolation. The earphones are offered in both semi-transparent black and fully transparent variants.

Accessories
The ST2 Pro Nebula comes with a handy carrying pouch and a USB type-C to A adapter plus three sets of silicone ear-tips for the version with the earphones.
Audio stuff - Cable alone
The ST2 Pro cable possesses sufficient power to effectively drive sensitive earphones, such as the Hidizs MP143 or the Dunu Kima 2, which I utilized during my assessment.
This cable features a neutral and balanced sound signature, enhanced by a slight touch of brightness. It is capable of delivering exceptional performance for all entry-level earphones and serves as an excellent alternative to portable USB DAC dongles, offering a more compact and lightweight solution while consuming significantly less power.
Equipped with the ES9281AC DAC chip, this cable provides superior sound quality in comparison to the standard codecs found in most similar products. The audio output is characterized by clarity and transparency, featuring deep and impactful bass, a melodious mid-range, and extended treble. The technical performance is commendable for a device of this nature, showcasing controlled low frequencies, well-defined mids, and energetic treble that avoids being overly sharp or harsh.
Although I would not suggest this cable for critical listening or for use with high-end earphones, it represents an excellent option for individuals seeking quality sound on the move without the inconvenience of a USB DAC dongle.

Audio stuff - Cable & bundled earphones
The ST2 Pro earphones, paired with a USB Type-C cable, feature the widely appreciated tuning that aligns with the popular H-2019 target curve. This entry-level earphone set is crafted for on-the-go listening across a variety of musical genres, and its tuning approach can be deemed effective.
The bass response is prominent and robust, showcasing excellent sub-bass extension along with a substantial mid-bass presence. Importantly, it avoids overwhelming the mid-range, maintaining a satisfying physical impact that is likely to resonate with fans of mainstream music. While the texture and resolution are adequate for this category, the tuning prioritizes enjoyment over tonal precision.
In terms of mid-range performance, it is not significantly recessed compared to typical V-shaped tunings, allowing for a clear and present sound with sufficient resolution. Vocals and instruments are rendered in a realistic and harmonious manner, exhibiting satisfactory timbre accuracy. However, the textures may lack refinement, resulting in a sound that feels somewhat flat and less emotionally engaging. Nonetheless, such critiques may be considered somewhat unjust given the earphones' intended purpose and market positioning.
The treble, while somewhat limited in resolution and definition, effectively integrates with the overall sound profile. It offers a lively and extended quality with a hint of brightness, without becoming sharp or fatiguing. The sound remains vibrant, avoiding any dullness, and the timbre does not exhibit excessive artificiality or lack of weight.
Overall, the Hidizs ST2 Pro presents a tuning that is well-suited to its intended use, complemented by satisfactory technical performance. The soundstage is adequately wide and spacious, providing good imaging capabilities. Although it may lack grandeur or depth, it avoids any sense of congestion or claustrophobia.

Conclusion
The Hidizs ST2 Pro Nebula cable is sufficiently well performing to establish its presence in a highly competitive market. This cable serves as an outstanding option for individuals seeking to enjoy their preferred earphones while on the move, without significantly increasing the bulk associated with their smartphone.
Furthermore, for those who do not yet possess a quality pair of earphones or are in search of an additional set, the Hidizs ST2 Pro Nebula cable can be purchased alongside its compatible earphones.
In any case, the Hidizs ST2 Pro delivers very good sound quality and superior craftsmanship at a reasonable price point.
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The review sample was kindly provided free of charge in exchange for an honest review. I don't use affiliate links. The Hidizs ST2 Pro is available through Kickstarter and regular sales will follow.
The prices are ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units) - ST2 PRO Nebula (Early Bird): $49.00 - ST2 PRO Nebula USB-C 2-pin or MMCX earphone cable only (Early Bird): $36.00.
Regular prices will be announced after the Kickstarter campaign ends.
To purchase please use the Kickstarter link.
Disclaimer: For various Google indexing reasons, parts of this review have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
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S
SatorArepo
Tnx for this
Headphones and Coffee
Previously known as Wretched Stare
Pros: Everything you need in a small package, providing fun and enjoyment.
Cons: Lightweight shells may feel cheap, sparse accessories, and may be too bright some

The Hidizs ST02 Nebula is a Single Dynamic driver IEM with a built in USB-C DSP Dac cable, this allows you to grab it and go without the need for other equipment. the cable can be switched so you can use it with your favorite dongle or portable player.
Inside the box is the IEM, a small pouch and the cable, a USB-C-to-A adapter and tips. The ST02 is lightweight and comfortable it is made of mostly plastic and has coin like faceplates. The cable is sturdy enough, but some may not like the nylon construction as it can tangle and kink.
Tech Specs:
Dac Chip: ES9281AC PRO
DSD Native: DSD64/128
PCM Support: up to 384kHz/32bit
MQA: Supported
Sampling rate indicator: Yes
Target H-2019 Curve
Dynamic Driver: 10mm Dual magnetic Pu-peek
Sensitivity: 108dB
Impedance: 32 OHM
Frequency Response: 20Hz-40kHz
High-purity oxygen-free copper 2-strand wire (0.78mm 2-Pin)
Customized Pouch/bag
Hi-Res Certification

Sound wise the DSP is tuned to give a bright Harman response with mild Sub-Bass impact and more focus on the Mid-Bass is typical Harman tuning with Sub-Bass rolling off fast and only a mild rumble when listening to boosted music. Mid-Bass hits fast and is very well controlled with nice texture.
Mids are mildly recessed with vocals being a little thicker than I was expecting, still everything sound as it should be, and nothing is out of sorts.
Treble is well extended with a nice natural tone, it is not the most detailed but has a nice smooth presentation that most will like.
Soundstage is wise with decent depth but nothing holographic are large, these are decently accurate but I wouldn't use them for gaming.
In a nutshell: The ST02 Nebula is good considering the cost and has potential, the selling point here is it's good to travel with for convenience and it has a enjoyable signature.
Kindlefirehditaly
New Head-Fier
Pros: Good build quality
Slightly improved comfort and fit
Extraordinary Performance for single DD
High-quality ESS chip
Bright V-shaped sound—Harman 2019
Good Macro & micro details
Quite and accurate Wide Soundstage
Pretty polished vocals
Extra light and comfortable setup
No need for cable upgrades
Slightly improved comfort and fit
Extraordinary Performance for single DD
High-quality ESS chip
Bright V-shaped sound—Harman 2019
Good Macro & micro details
Quite and accurate Wide Soundstage
Pretty polished vocals
Extra light and comfortable setup
No need for cable upgrades
Cons: No App for DSP control or custom EQ
Shell could be better
Tips needs upgrade
Treble spark are bright (Great for me but maybe not for you)
Lack of subbass (subjetive)
MQA is really needed?
Shell could be better
Tips needs upgrade
Treble spark are bright (Great for me but maybe not for you)
Lack of subbass (subjetive)
MQA is really needed?
Disclaimer:
After several months of waiting, the Hidizs ST2 Pro Nebula finally comes to life. Due to some unforeseen circumstances, the release of this product was postponed, but the wait was worth it.Finally, an IEM arrives that integrates a particularly refined ESS chip into the cable and not the usual Realtek or Conexant.
The cable in this set is definitely the strongest and most interesting piece. Given its power and connector (which can also be requested in other versions), it is suitable for various HIDIZS models, especially the Mermaid series.
However, the review will still be 100% honest and in no way biased.
I’m not an audiophile; I’m just a guy that likes to test out different IEMs and DACs and spends a lot of time listening to music.
So I’m not going to use super technical words to review it, but I will do my best to describe it.
Tech Specs:
The specifications I report below are taken directly from the packaging.- Dac Chip: ES9281AC PRO
- DSD Native: DSD64/128
- PCM Support: up to 384kHz/32bit
- MQA: Supported
- Sampling rate indicator: Yes
- Target H-2019 Curve
- Dynamic Driver: 10mm Dual magnetic Pu-peek
- Sensitivity: 108dB
- Impedance: 32 OHM
- Frequency Response: 20Hz-40kHz
- High-purity oxygen-free copper 2-strand wire (0.78mm 2-Pin)
- Customized Pouch/bag
- Hi-Res Certification
- Supe Early Bird Price: 39.00 USD – Early Bird Price – 49.00 USD – Full Price: 89.00 USD
- Launch Date: 19 December 2024
Packaging:


The packaging of the New Hidizs ST2 Pro Nebula is particularly simplified; the packaging immediately shows the ST2 Pro and underneath we find the Nebula Cable. The accessories included are:
- Transport bag
- Nebula Cable
- 3 pairs of tips
- A Type c to USB adapter
- Manual & Warranty card

The standard equipment is complete, and the adapter is always convenient to have included to be able to use the IEMs on all devices. As for the tips, the model seems very cheap to me. I don’t think they are the best tips that could be included.
Design/Build Quality:

In terms of build quality, the Hidizs ST2 Pro Nebula does not particularly stand out in my hands. The build quality is slightly superior to the Hidizs Galaxy. The general finishing is good but the substance is more or less the same. At the time of writing the review, I do not yet know the final price, but I hope it is in line with the materials used. As we can see, the faceplates have a gold-colored metal insert, and the shells are in smoked black plastic (perhaps resin). We have a ventilation hole near the connector (behind the driver) and one placed in the internal part near the nozzle (in front of the driver). Nozzle with a metallic finish similar to nozzles already seen on Hidizs products.

The most interesting part comes with the cable that integrates a nice DAC chip, namely, ES9281AC Pro with excellent performance. The connector with 2 visible windows allows you to see the various components inside. The cable is covered in fabric but remains very flexible and light. Microphone and button are present. Overall, it’s a very light set; no component feels heavy. Obviously, to the touch, it all feels a bit cheap.
However, this feeling does not have to be negative. It could be a choice to contain costs or to keep the set ultra light.
Initial Sound Impressions:

Somehow the Hidizs ST2 Pro Nebula is quite surprising, despite the single driver managing to express every frequency with a certain crispness. Although the target is the usual Harman 2019 this version is definitely brighter and closer to the mid-highs. For a single driver per side, the representation is absolutely very interesting, especially for the cleanliness and precise staging, even if not wide. Each sound has a millimetric placement in space, arriving at the eardrum extremely clearly. I can’t say if it is the cable or the IEM, but doing some tests I will surely be able to establish where the magic lies. Limited sub-bass but quite precise and dry bass.
Comfort/Fit:

The shape of the Hidizs ST2 Pro Nebula shells resembles that of the Mermaid series so the fit is almost unchanged. Their lightness does not cause heaviness on the ears. The cable is very flexible and comfortable. The Type C connector is compact enough not to be annoying.
Equipment used for testing above:
Device:- OSX
- Poco M4 Pro
- Amazon Music UHD 24bit 96kHz (Both)
- Built In
IEM Swap on Nebula:

The connector is a two-pin 0.78mm Hidizs format. It also fits other IEMs, but the greatest stability is found by staying with the same brand. The first IEM I had in front of my eyes was the Kefine Klean. In order not to go straight to a Hidizs MS3, I decided to try the Klean. Surprise surprise, the sound is very similar, with some points in favor of the Klean, which have gained sparkle. Let’s say that, as I expected, the cable does a lot of magic in the final result. The most obvious flaw in a similar product is the lack of an app to manage it.


Ok the Kefine Klean sound good but the connector inserts with little resistance.
Let’s try the Hidizs MS3 now; surprisingly, the connector grip is poor here too. In terms of sound, the low range is maintained much better than the previous IEMs. However, the sound is actually very similar, but the definition of the MS3 is on a whole other level. The Nebula cable, if sold at the right price, could really be a great product. I would just add a classic 0.78mm with a slightly higher grip.
Final sound impression:

The Hidizs ST2 Pro with the Nebula cable is a great match. But what gives even more joy is when you take the cable and use it with other IEMs, where you notice the true potential enclosed in a small ESS chip. The MS3 becomes truly absurd with an extremely resolute representation. But returning to the performance of the ST2 PRO as anticipated, it does not seem to have a single driver in your ears. Honestly, at first glance, the quality of the headphones does not seem to be very far from the MS1 Galaxy; perhaps the choice of materials should have been slightly different. What undoubtedly costs is the cable, and it is also what takes these IEMs to a higher level. I would like to point out that my evaluation is given with the SS20 tips. The stock ones did not guarantee me an optimal sealing.
Bass:
I would call it a dry and precise bass; the sub-bass is limited and the roll-off is very fast, but the whole thing is very natural and composed. In terms of purity of sound, there is no emphasis but a fairly linear response with a clean and short kick. Honestly, a more faithful representation in some tracks and others a little less, but if the track requires it, the potential is heard.Mids:
Some have called them recesses, but I don’t think so. Perhaps graphically, they may seem so but to my ears, the voices come through clear and limpid, perhaps only second to the treble. The male and female voices are almost at the same level, silky, sinuous, and with the right tone and weight that enriches them, making them very real. Excellent also the whole set of musical instruments that accompany the voices on the same level.Treble:
Treble very sparkling but never harsh or sibilant; a meticulous work of perfecting the DSP has made the treble extremely rich in macro and micro details (obviously not like on some hybrid IEMs), especially if you consider the single driver. A truly excellent result with trebles with an excellent extension that make listening full of air and energy. Obviously a bit of resolution is missing that can be achieved with other types of drivers.Soundstage and Imaging:
As for the soundstage, it is not huge, but the DSP works very cleanly with a clear and precise image that allows a precise placement of sounds in a space. There are IEM Hidizs that obviously do better, but this remains, in my opinion, an excellent result.Comparison:
A correct comparison should be made with products that have a DSP, but currently the only one that comes to mind is the Simgot EW300 DSP.Vs. Simgot EW300 DSP

Simgot worked much more on the IEM than on the cable and produced an IEM with an incredible quality ratio. Honestly, the metal shell is really beautiful; the DSP is cheaper, at least in the chip used, but the result we can say is excellent. Simgot fills the lack of the DAC with a hybrid IEM that integrates what the chip cannot do. Very aggressive and interesting price.
Vs. Kefine Klean

Is a type C cable that integrates a DSP absolutely necessary? In my opinion, it is not absolutely mandatory that there is one; in fact, an IEM if it sounds good without tricks will sound good even years after having changed a thousand cables. The Kefine Klean is an economic example, together with the Delci, of how you can get an excellent product at a low price. Does the DSP make sense? Absolutely yes, but it should be sold above all as an accessory and perhaps integrate an app to make your own presets. The Klean sounds very good with the Nebula cable, but the connector does not make a grip that I would define as optimal. Evidently, the pins are slightly thinner than normal.
Conclusion:

In the meantime that I’m writing, I don’t know the final price yet. Honestly, I hope the product settles on a price under 100 USD. This is because if we take for example, the Simgot EW300 DSP, it has an extremely low price. Okay, they have a much cheaper type C cable but the IEM is much more elaborate. I think in a certain sense they can be compared to each other. I really like the cable, and I think it will be sold separately because they also wanted to send me an MMCX variant. The product promises to be 360° compatible with any product that supports audio on type C output (including new iPhones); the microphone in a call I made worked very well. In my opinion, the product is approved, but I would raise the construction quality and choice of materials a little.
Update 5/12/24 Price Reveal:

Now that I know the final price, many things make more sense. The launch price is set at $39 for the ST2 Pro + Nebula version, which is truly excellent. I had seen a price written as “XXX.00,” and I was somehow expecting a price above $100. Which honestly speaking would have been totally out of the market. The cable alone is priced at $36. So the ST2 Pro is indeed very cheap, as it seems. The price is certainly excellent but at least in my case, the 0.78mm pins of the Nebula have a little low resistance when inserted into other IEMs. The price itself is mostly made up of the cost of the ESS chip.
Could I abandon all else and focus just on the Hidizs ST2 PRO Nebula? Absolutely, because the quality is superb in my opinion; nevertheless, remember to change the eartips!
More information (no affiliations):
HIDIZS ST2 PRO Nebula 2-in-1 High-Performance DAC & USB-C HiFi Digital In-ear EarphonesKickstarter Hidizs ST2 Pro Nebula
Jadedgem
New Head-Fier
Pros: Great allrounder
Very nice mid bass
Very nice DSP Cable
2 in 1 Earphone plus Dac/amp
Comfort- replaces the need for a separate Dac/amp
Very nice mid bass
Very nice DSP Cable
2 in 1 Earphone plus Dac/amp
Comfort- replaces the need for a separate Dac/amp
Cons: Not for vocal lovers
Stock ear tips not so good
Stock ear tips not so good

Hidizs ST2 Pro Nebula review
I am an audiophile from sunny South Africa. I already use one Hidizs earphone many times a week. The MS1 Galaxy is always in my gym bag and is my go-to earphone for gym so I was pretty exited when Hidizs contacted me for a review on their new project the ST2 Pro Nebula. This review is my own and I receive no money from Hidizs for this review. Like my previous Hidizs packages the Nebula shipped really quick and was delivered to my door in about 21 days. This is the details for the Kickstarter project of the Nebula.
Kickstarter Launch Date: December 19th, 2024, at 10:30 AM (EST)
Pricing Details:
ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units)
ST2 PRO Nebula (Early Bird): $49.00
ST2 PRO Nebula USB-C DSP 0.78mm 2-pin/MMCX Earphone Cable (Early Bird): $36.00
Kickstarter Link

Unboxing
The Kickstarter price in South Africa comes out to R899. The Nebula shipped in a small, square two-piece cardboard box that is very sturdy. On the front is a picture of the earphone and the specs are at the back. When you lift the one piece off the other you find the Nebula shells peaking at you and it looks like a display you find in a coin collection because the Hidizs logo on the top plate looks like an old collectable coin. Underneath that you will find a USB-C TO USB converter, cable and your ear tips. Overall, I am happy with packaging and overall display for the price.

Specs
Dac Chip: ES9281AC PRO
DSD Native: DSD64/128
PCM Support: up to 384kHz/32bit
MQA: Supported
Sampling rate indicator: Yes
Target H-2019 Curve
Dynamic Driver: 10mm Dual magnetic Pu-peek
Sensitivity: 108dB
Impedance: 32 OHM
Frequency Response: 20Hz-40kHz

Connectivity
The Nebula shipped with a really cool cable that has a Next Gen DSP Cable that features a really cool Dac chip the ES9218AC with a very sufficient output up to 70mW+70mW@32Ω and drives the Nebula with ease. This makes the Nebula a 2 in 1 device as there is no need for a separate Dac/amp or dongle to go from USB-C TO 3.5mm. The Nebula DSP cable worked on all my phones like the Samsung S21, Huawei P40 Lite and LG V40. It did however not work on my Oppo A78 but that is not a fault on Hidizs side as that Oppo battles to connect to most Dac/amps I own. So, if you have an Oppo make sure of compatibility before buying. I also connected the Nebula to the Hiby M300 Dap and that was my favorite pairing all throughout. There was so much headroom on HIBY Player that the volume I preferred was hardware volume 9 and at 12 it started to get uncomfortably loud.

Look & Build
I really like this type of ear-shells from Hidizs as with the MS1 Galaxy which is the most comfortable fit out of all the earphones that I own the Nebula fits just as snug. The very light shells make the Nebula a very non fatiguing earphone and that is a huge plus. The shells themselves are really plain and transparent and a nice touch is the coin like Hidizs logo on the top plates. In design less is more. The DSP cable is the real star here and it grew on me very quickly. It is made from the same material used as parachute rope and it adds a certain cool factor for me as I am so used to braided cables that this is refreshing and very welcome. The Dac chip part which plugs into your phone’s USB-C port and I was scared at first because when you walk with a dongle connected to your phone in your pocket sometimes the connection comes loose. This was not the case at all and I found the connection very secure when carried around in pocket connected to phone. I like the leather pouch a lot and it is also refreshing to not just a canvas or leather case. So, Hidizs was thinking outside the box here and I like it. The pouch also has a magnetic top part that just slams together once you put the earphone in for storage. I have to say the only thing I did not like on the Nebula is the stock ear tips. Wide bore tips really gave a very good sense of realism to the vocals which the stock tips did not do.

Sound
To get a feel for the Nebula sound signature I plugged it into the Hiby M300 and went straight to Tidal through Hiby player. The first song I chose was Tori by the Nicolas Parent Trio and oh boy this song gives me an impression on an earphone really quick as the song has got a lot going on with different sounds, transients and overall imaging and stage. I also used the stock tips and stock cable for my first impressions. First thing I noticed was a very creamy bottom end. There is a drum roll near the end of the song that sounded really good on the Nebula.
I would say the bass is mid bass focused but there is sub bass at hand when required as on Massive Attack’s song Angel. I wanted to explore the bass a bit further and I fitted some Penon Liqueur Black tips. Listened to the same song and it sounded like I was sitting inside an SQ car at a competition car show. You know that nice tight bass. I also found that the nebula did much better with bassier instruments like the Cello and Bass guitar vs Violin and Electric guitar. I loved the lower notes on Comme un Tango by Vincent Belanger and Anne Basson and the lower notes trumped the Violin. The Cello performance on Adam Ben Ezra- Can’t stop running was so good it made me listen to the song twice and you can clearly differentiate when the string is being plucked and the reverb that follows.
With the mids being recessed I found the vocals to not be so good and if you are a vocal lover this set is not for you. I think it is more the stock tips than the Nebula itself as when I fitted some wide bore tips the vocals opened up and the voices had a much more realistic feel to them and Bryan Adams had so much emotion in his voice on Thought I died and gone to heaven. The higher notes on the Electric guitar also became much more forward. The male vocals sounded better to me than female voices as the female voices just had a bit of sparkle missing on top while male vocals like Jeff Buckley’s voice sounded so wonderful on Lover, you should have come over. This is also where the Acoustic guitar shined and every instrument and vocals just blended in perfectly together.
When I listened for highs one of my favorite tracks is Crystal Ribbon (Extended Smelting). On this track if you have a bright earphone, you get fatigued very quickly and I am happy to report that the treble has a warm feel to it for me. Contact by Daft Punk is one of my go-to songs for highs as some of the stuff going on in that mix can reach pretty high and the Nebula kept up really well. With a song like Kyla La Grange- Cut Your Teeth (Kygo Remix) you will not keep your earphones in your ears if they are bright and it was a very pleasant listen even though I had to kick the volume down two nudges.
There is absolutely no fatigue and even though I also listened for sibilance I found non even on well known sibilant tracks like On the Border by Al Stewart and The Cowboy Junkies - Sweet Jane. These two tracks are torture to listen to when you have a sibilant earphone. The Nebula passed that test with flying colors. The Nebula has great pace, rhythm and timing and if you get the Nebula, please listen to Honky Tonk Women by The Rolling Stones. There is some foot tapping goodness going on with the Nebula and that song.
I really liked the soundstage on the Nebula. On Tool- Chocolate Chip Trip it was a total out of head experiencing as the stage is moderately wide but very deep. The song also has a lot going on and the Nebula kept up well with this busy track. I also need to mention that the Nebula has very good holographic imaging as I was listening for a 3d effect which is greatly done by Peter Gabriel on the Security album. The Nebula was so engaging I listened to the whole album and really enjoyed it.
Regarding the DSP cable, I used it with some of my other earphones to and the chip had ample power to drive most I tested it with and the ES chip is really good sound wise.

Conclusion
My conclusion is that the Nebula to me is for everyone and I think everyone from audiophiles to music lovers and gamers should buy it. If you are looking for a nice affordable set of earphones that does not break the bank and comes with a premium DSP cable and something that sounds good with most genres then the Nebula is for you. I would strongly advise you to order a set of wide bore ear tips from any manufacturer as I found that various brand wide bores unlock some real magic with the Nebula.

littlenezt
100+ Head-Fier
Pros: +Simplicity
+Good DAC Performance
+Build Quality (Cable)
+Comfortable
+Tuning
+Good DAC Performance
+Build Quality (Cable)
+Comfortable
+Tuning
Cons: -Build Quality (IEM)
-Technicality (IEM) with other cable
-Technicality (IEM) with other cable
Hidizs ST2 Pro Nebula
1DD + USB C ES9281AC Pro
$39 on Kickstarter
https://hidizs-1.kckb.me/8b96ad1c (affiliate)
Started on Dec 19th, and is already fully funded in just 1 minute.

Before I begin this review, let me thank Hidizs for sending the Nebula for this review.
Rest assured, my review is always 100% my own personal opinion.
Unboxing
What you get inside the box :
Build Quality


The IEM itself, to be brutally honest with you, feels a bit cheap, it’s made out of plastic, though on the plus side, because of it, the IEM itself is basically weightless, and is comfortable to use.

The cable is terminated in USB C and I believe Hidizs also sell this cable as a cable only and also available in mmcx configuration.
And what is so special about this cable? It has a built-in DAC, it also has a mic that sounds decent for phone calls.

As for the cable itself, it’s pretty good, it has some kind of nylon coating, and you can see the chip on the cable itself.
Probably the main selling point of the whole package here is the cable.
Sound
Tested using the stock cable, KZ cable, stock eartips
Music is mostly from Apple Music and Spotify (J-POP, Rock, EDM, Metal, Jazz, Rap)
I have to be completely honest with you since I don’t have a measuring rig. I'm not sure if the cable is adding some sort of EQ slightly to the IEM out of the box as stock configuration or the cable is just providing pure sound quality without any tuning from the cable.
With the KZ Cable, the Nebula sounds almost identical to its USB cable, though it feels a bit more un-polished.
Hidizs on their website also said that the cable itself has DSP capabilities and can do EQ, but I don’t find any special apps and how to set the DSP / EQ itself.
With all stock configuration, the Nebula sounds just like a Harman target with extra mid bass. It has a strong bass presence, overall sound is on the warmer side and is very comfortable to listen to for a long listening session, or you can say the tonality is fatigue free.
Bass : Has a Harman target sub-bass quantity, with extra mid-bass presence, the bass with the included cable, sounds very nice, like it feels enveloping you with its mid-bass presence.
Sub-bass also digs in quite deep, and overall bass presentation is on the bouncier side rather than pure brute force punch.
For the metal genre, I feel like the bass is a bit too sluggish to keep up with double pedal kick drums.
But for other genres, let's say J-POP, Rap, EDM, the bass is very nice to listen to.
Midrange : Harman target tuned, with slight boosted lower mids due to coloration from the bass.
Overall the midrange feels thick, I won’t call it particularly muddy, but it feels thick.
Vocal sounds very well bodied and presented in a very musical way and is free from sibilance, also probably thanks to the high quality built in DAC, the vocal sounds very lush and pleasing with lots of emotion, I can say this because with the KZ cable, the vocal sounds a bit lifeless.
Same for instruments, It sounds thick and well bodied.
Tested on Violet Evergarden OST, “The Ultimate Price” you can hear that piano and violin sounds thick and lush, it is never presented in an aggressive manner, or you can say, it is presented in a very smooth and relaxed side rather than aggressive.
Treble : Smooth, relaxed, with OK extension.
The overall treble presentation here is pretty relaxed, though I checked on others' squig graphs, there’s a peak around 8k, I don’t hear it in real life.
Treble is presented just like your typical Harman target tuned IEMs, smooth, decent air quality but just OK extension.
As for the details for the treble, it's pretty good, thanks to the built-in DAC, because when I test the Nebula with KZ cable straight to my phone, the details are just not there.
Technicalities
Good for $39USD (If used using stock cable)

Stage : Medium Sized
Has decent stage layering, it feels symmetrical in width and depth but exact wall placement rendering is slightly blurry.
Imaging : Good
I won’t say that it has holographic imaging, but it’s good, like pretty good, again, probably due to the built-in DAC from the cable. With KZ cable plugged straight to my smartphone the Nebula has a decent imaging at best.
Separation & Positioning : Good
The ST2 Pro Nebula has a good separation for a single driver IEM, again thanks to the built-in DAC (probably at this point I just sounded like a broken records)
As for positioning it's decent, I can pinpoint objects and sound source but not like razor sharp pinpoint positioning, with the Nebula I kinda need to focus a bit more to be able to pinpoint where this sound / objects are coming from.
Comparison
As for comparison, I honestly don’t really use a USB IEM, so I can’t really give a straight comparison between the same USB type IEM, but just ask away in the comments, I will try my best to reply.
Conclusion
Is the Hidizs ST2 Pro Nebula worth it?
To be honest if the price stays at $39USD for the complete IEM + Cable package, yeah it's worth it, But I believe the normal MSRP price for this is $49USD, at that price bracket, there are quite a lot of other IEM that I can recommend (provided lets say, you already have some kind of external DAC or dongle).
The use case scenario I can see with the ST2 Pro Nebula is for an EDC item, or everyday carry item, like where simplicity is really needed but you don’t want to be limited by the battery life of a TWS solution or poor sound quality from a similarly priced TWS as the Nebula.
I can say that the sound quality of the Nebula for $39 - $49 USD is better than similarly priced TWS solutions or bluetooth headphones.
So in the end, it is up to you as consumers to decide whether the ST2 Pro Nebula fits in with your use case scenario or not.
That’s all from me for now, thanks for reaching this far !
You can watch the video version of this review here
-littlenezt.
1DD + USB C ES9281AC Pro
$39 on Kickstarter
https://hidizs-1.kckb.me/8b96ad1c (affiliate)
Started on Dec 19th, and is already fully funded in just 1 minute.

Before I begin this review, let me thank Hidizs for sending the Nebula for this review.
Rest assured, my review is always 100% my own personal opinion.
Unboxing
What you get inside the box :
- IEM
- Cable
- Eartips
- Warranty Card
- Pouch
- USB C to A Adapter
Build Quality


The IEM itself, to be brutally honest with you, feels a bit cheap, it’s made out of plastic, though on the plus side, because of it, the IEM itself is basically weightless, and is comfortable to use.

The cable is terminated in USB C and I believe Hidizs also sell this cable as a cable only and also available in mmcx configuration.
And what is so special about this cable? It has a built-in DAC, it also has a mic that sounds decent for phone calls.

As for the cable itself, it’s pretty good, it has some kind of nylon coating, and you can see the chip on the cable itself.
Probably the main selling point of the whole package here is the cable.
Sound
Tested using the stock cable, KZ cable, stock eartips
Music is mostly from Apple Music and Spotify (J-POP, Rock, EDM, Metal, Jazz, Rap)
I have to be completely honest with you since I don’t have a measuring rig. I'm not sure if the cable is adding some sort of EQ slightly to the IEM out of the box as stock configuration or the cable is just providing pure sound quality without any tuning from the cable.
With the KZ Cable, the Nebula sounds almost identical to its USB cable, though it feels a bit more un-polished.
Hidizs on their website also said that the cable itself has DSP capabilities and can do EQ, but I don’t find any special apps and how to set the DSP / EQ itself.
With all stock configuration, the Nebula sounds just like a Harman target with extra mid bass. It has a strong bass presence, overall sound is on the warmer side and is very comfortable to listen to for a long listening session, or you can say the tonality is fatigue free.
Bass : Has a Harman target sub-bass quantity, with extra mid-bass presence, the bass with the included cable, sounds very nice, like it feels enveloping you with its mid-bass presence.
Sub-bass also digs in quite deep, and overall bass presentation is on the bouncier side rather than pure brute force punch.
For the metal genre, I feel like the bass is a bit too sluggish to keep up with double pedal kick drums.
But for other genres, let's say J-POP, Rap, EDM, the bass is very nice to listen to.
Midrange : Harman target tuned, with slight boosted lower mids due to coloration from the bass.
Overall the midrange feels thick, I won’t call it particularly muddy, but it feels thick.
Vocal sounds very well bodied and presented in a very musical way and is free from sibilance, also probably thanks to the high quality built in DAC, the vocal sounds very lush and pleasing with lots of emotion, I can say this because with the KZ cable, the vocal sounds a bit lifeless.
Same for instruments, It sounds thick and well bodied.
Tested on Violet Evergarden OST, “The Ultimate Price” you can hear that piano and violin sounds thick and lush, it is never presented in an aggressive manner, or you can say, it is presented in a very smooth and relaxed side rather than aggressive.
Treble : Smooth, relaxed, with OK extension.
The overall treble presentation here is pretty relaxed, though I checked on others' squig graphs, there’s a peak around 8k, I don’t hear it in real life.
Treble is presented just like your typical Harman target tuned IEMs, smooth, decent air quality but just OK extension.
As for the details for the treble, it's pretty good, thanks to the built-in DAC, because when I test the Nebula with KZ cable straight to my phone, the details are just not there.
Technicalities
Good for $39USD (If used using stock cable)

Stage : Medium Sized
Has decent stage layering, it feels symmetrical in width and depth but exact wall placement rendering is slightly blurry.
Imaging : Good
I won’t say that it has holographic imaging, but it’s good, like pretty good, again, probably due to the built-in DAC from the cable. With KZ cable plugged straight to my smartphone the Nebula has a decent imaging at best.
Separation & Positioning : Good
The ST2 Pro Nebula has a good separation for a single driver IEM, again thanks to the built-in DAC (probably at this point I just sounded like a broken records)
As for positioning it's decent, I can pinpoint objects and sound source but not like razor sharp pinpoint positioning, with the Nebula I kinda need to focus a bit more to be able to pinpoint where this sound / objects are coming from.
Comparison
As for comparison, I honestly don’t really use a USB IEM, so I can’t really give a straight comparison between the same USB type IEM, but just ask away in the comments, I will try my best to reply.
Conclusion
Is the Hidizs ST2 Pro Nebula worth it?
To be honest if the price stays at $39USD for the complete IEM + Cable package, yeah it's worth it, But I believe the normal MSRP price for this is $49USD, at that price bracket, there are quite a lot of other IEM that I can recommend (provided lets say, you already have some kind of external DAC or dongle).
The use case scenario I can see with the ST2 Pro Nebula is for an EDC item, or everyday carry item, like where simplicity is really needed but you don’t want to be limited by the battery life of a TWS solution or poor sound quality from a similarly priced TWS as the Nebula.
I can say that the sound quality of the Nebula for $39 - $49 USD is better than similarly priced TWS solutions or bluetooth headphones.
So in the end, it is up to you as consumers to decide whether the ST2 Pro Nebula fits in with your use case scenario or not.
That’s all from me for now, thanks for reaching this far !
You can watch the video version of this review here
-littlenezt.
Last edited:
o0genesis0o
Headphoneus Supremus
Pros: + Punchy, impactful mid-bass
+ The USB DAC cable has the highest handling and comfort so far
+ Interesting soundstage shape with some content
+ The USB DAC cable has the highest handling and comfort so far
+ Interesting soundstage shape with some content
Cons: - Recessed and rather boomy midrange
- Vocals lack a sense of vibrancy and “shine”
- Vocals lack a sense of vibrancy and “shine”
Today, we look at a new release from Hidizs, the ST2 Pro Nebula. This IEM is an attempt to combine Hidizs expertise as an electronics manufacturer with their emerging reputation as an IEM maker.
The earpieces of ST2 are definitely designed for cost-effectiveness. It consists of two injection molded plastic pieces snapped and glued together to form a hollow shell for the driver. On the plus side, the nozzles are constructed from metal and feature a lip to help retaining the ear tips.
Comfort-wise, I had quite a bit of problem with the stock silicone ear tips that come with my pre-production unit. Simply put, the short and soft ear tips do not work well with the relatively short nozzles of ST2, making it quite tricky to achieve a stable seal. For IEMs like ST2, in my experience, you should use ear tips with a longer stem and sticky nozzles to compenstate for the nozzle length. I opted for Pentaconn Coreir AL ear tips for the rest of my listening tests with ST2.
The key “accessory” of ST2 is, of course, the USB DAC cable. Simply put, you can think of it as an Apple dongle with built-in IEM cable. I will discuss this cable later in this review.
Timbre:
ST2 has a rather unique sound signature that does not align with any other IEM in my database. The best way to describe it is a bass-focused V-shaped sound signature. In other words, ST2 is unabashedly “casual.” It does not aim for a “neutral” “audiophile-approved” tuning nor does it aim for a sub-bass focused tuning so that “you can feel the bass without bass bleed.” No, this IEM embraces mid-bass and utilises a surprisingly capable dynamic driver to execute that vision. ST2 is punchy, thumpy, and unabashedly recessed and boomy.
At the same time, Hidizs shows restrain and maturity with the tuning of the other end of the spectrum. As a result, ST2’s upper midrange and treble are generally smooth with minimal sibilance or shoutiness. The benefit of this tuning choice is that you can turn the volume even louder to soak in that mid-bass boom boom.
Percussion, Bass, and perceived dynamic:
Bass response, particularly mid-bass, is the highlight of ST2 sound signature. The frequency response of ST2 ensures that the sounds listeners commonly associate with “bass” such as kick drums and the slaps and plucks of bass guitars are highlighted over other elements in the mix. The exaggerated amount of bass is accompanied by surprisingly competent bass quality to create impactful bass line that also feels “tight” and snappy. The only aspect where the bass of ST2 falters is the sub-bass extension. Simply put, this IEM does not “growl” or “rumble” as much as you would expect when you compare to modern IEMs with a sustained boost below 50Hz. As a result, if your music relies on sub-bass rather than mid-bass, you might find the bass somewhat lacking.
Resolution:
ST2 does not break the mold of a single DD in terms of both instrument separation and detail retrieval. Weak extension into the upper treble is an expected weakness that pulls down the perceived technical performance. The tuning choice to emphasise bass and recess the midrange also negatively impact the perceived clarity of this IEM. That said, ST2 does not fall behind the expected level of good DD from yester-years such as the venerable Moondrop Aria 2021. The snappy, tactile physical sensation from the bass also gives this IEM a slight boost in the perceived incisiveness.
Stereo imaging and soundstage:
The soundstage of ST2 is rather unusual due to its tuning. The thick mid-bass and lower-midrange emphasis does narrow down the soundstage, but exaggerates the depth illusion in return. For example, on some tracks, the front-left and front-right elements in the mix can feel like they pop out from the stage to hover slightly in front of my face, to the sides. Moreover, this IEM tends to place sound elements further toward the back of my head. It’s hard to say whether this presentation is better or worse, but it’s a bit different, making it interesting.
Where ST2 really shines is in FPS gaming. ST2 is one of the rare IEMs that can convey the illusion of gunshots coming from the front of the head. Whilst ST2 does not have tack sharp positioning of sound elements, I find this IEM to be quite competent for gaming. If you are skilled, you might be able to gain competitive advantage with ST2.
As I mentioned, ST2 is packed with a USB DAC cable. The immediate question would be whether the cable “transparent” or it has some sorts of baked in EQ. As you can see from the frequency response measurement below, the response of ST2 remains unchanged when swapped to an analog cable. This result suggests that the USB DAC cable is “transparent.”
Regarding the DAC itself, I found the cable to sound clearer, more spacious, and more dymamic than the plain old Apple dongle. According to the official spec sheet, it seems that ESS ES9281AC PRO chip provides both DAC and amplification. The volume curve seems to be set quite aggressively, similarly to other USB DAC cables on the market, meaning this DAC gets very loud even at low volume with all of my devices, from HiBy R3II to MacBook.
What I like about this IEM:
What could be improved:
Updated: December 20, 2024
Forewords
- What I look for in an IEM is immersion. I want to feel the orchestra around my head, track individual instruments, and hear all of their textures and details. I’m not picky about tonality, as long as it does not make the orchestra, violin, cellos, and pianos sound wrong.
- I rate IEMs within with a consistent scale from 1 (Poor) to 3 (Good) to 5 (Outstanding). An overall ranking of 3/5 or above is considered positive.
- Ranking list and measurement database are on my IEM review blog.
- The terminology for subjective impressions in this review is based on the Audio Wheel for reproduced sound defined in the technical report ITU-R BS.2399-0
- This review is based on a pre-production sample from Hidizs (Thank you!). I have no affiliation with or financial interest in Hidizs.
- This IEM would be released on Kickstarter. The campaign would be launched in December 2024 and units would be shipped in February 2025. The early bird price of the IEM is $39. Refer to Kickstarter page for more detail.
General Information

Non-sound Aspects


The earpieces of ST2 are definitely designed for cost-effectiveness. It consists of two injection molded plastic pieces snapped and glued together to form a hollow shell for the driver. On the plus side, the nozzles are constructed from metal and feature a lip to help retaining the ear tips.
Comfort-wise, I had quite a bit of problem with the stock silicone ear tips that come with my pre-production unit. Simply put, the short and soft ear tips do not work well with the relatively short nozzles of ST2, making it quite tricky to achieve a stable seal. For IEMs like ST2, in my experience, you should use ear tips with a longer stem and sticky nozzles to compenstate for the nozzle length. I opted for Pentaconn Coreir AL ear tips for the rest of my listening tests with ST2.
The key “accessory” of ST2 is, of course, the USB DAC cable. Simply put, you can think of it as an Apple dongle with built-in IEM cable. I will discuss this cable later in this review.
Sonic Performance
Timbre:





ST2 has a rather unique sound signature that does not align with any other IEM in my database. The best way to describe it is a bass-focused V-shaped sound signature. In other words, ST2 is unabashedly “casual.” It does not aim for a “neutral” “audiophile-approved” tuning nor does it aim for a sub-bass focused tuning so that “you can feel the bass without bass bleed.” No, this IEM embraces mid-bass and utilises a surprisingly capable dynamic driver to execute that vision. ST2 is punchy, thumpy, and unabashedly recessed and boomy.
At the same time, Hidizs shows restrain and maturity with the tuning of the other end of the spectrum. As a result, ST2’s upper midrange and treble are generally smooth with minimal sibilance or shoutiness. The benefit of this tuning choice is that you can turn the volume even louder to soak in that mid-bass boom boom.
Percussion, Bass, and perceived dynamic:

Bass response, particularly mid-bass, is the highlight of ST2 sound signature. The frequency response of ST2 ensures that the sounds listeners commonly associate with “bass” such as kick drums and the slaps and plucks of bass guitars are highlighted over other elements in the mix. The exaggerated amount of bass is accompanied by surprisingly competent bass quality to create impactful bass line that also feels “tight” and snappy. The only aspect where the bass of ST2 falters is the sub-bass extension. Simply put, this IEM does not “growl” or “rumble” as much as you would expect when you compare to modern IEMs with a sustained boost below 50Hz. As a result, if your music relies on sub-bass rather than mid-bass, you might find the bass somewhat lacking.
Resolution:

ST2 does not break the mold of a single DD in terms of both instrument separation and detail retrieval. Weak extension into the upper treble is an expected weakness that pulls down the perceived technical performance. The tuning choice to emphasise bass and recess the midrange also negatively impact the perceived clarity of this IEM. That said, ST2 does not fall behind the expected level of good DD from yester-years such as the venerable Moondrop Aria 2021. The snappy, tactile physical sensation from the bass also gives this IEM a slight boost in the perceived incisiveness.
Stereo imaging and soundstage:


The soundstage of ST2 is rather unusual due to its tuning. The thick mid-bass and lower-midrange emphasis does narrow down the soundstage, but exaggerates the depth illusion in return. For example, on some tracks, the front-left and front-right elements in the mix can feel like they pop out from the stage to hover slightly in front of my face, to the sides. Moreover, this IEM tends to place sound elements further toward the back of my head. It’s hard to say whether this presentation is better or worse, but it’s a bit different, making it interesting.
Where ST2 really shines is in FPS gaming. ST2 is one of the rare IEMs that can convey the illusion of gunshots coming from the front of the head. Whilst ST2 does not have tack sharp positioning of sound elements, I find this IEM to be quite competent for gaming. If you are skilled, you might be able to gain competitive advantage with ST2.
USB DAC Cable
As I mentioned, ST2 is packed with a USB DAC cable. The immediate question would be whether the cable “transparent” or it has some sorts of baked in EQ. As you can see from the frequency response measurement below, the response of ST2 remains unchanged when swapped to an analog cable. This result suggests that the USB DAC cable is “transparent.”

Regarding the DAC itself, I found the cable to sound clearer, more spacious, and more dymamic than the plain old Apple dongle. According to the official spec sheet, it seems that ESS ES9281AC PRO chip provides both DAC and amplification. The volume curve seems to be set quite aggressively, similarly to other USB DAC cables on the market, meaning this DAC gets very loud even at low volume with all of my devices, from HiBy R3II to MacBook.
Gallery
Conclusions
What I like about this IEM:
- Punchy, impactful mid-bass
- The USB DAC cable has the highest handling and comfort so far
- Interesting soundstage shape with some content
What could be improved:
- Recessed and rather boomy midrange
- Vocals lack a sense of vibrancy and “shine”

Updated: December 20, 2024

FreeWheelinAudioLuv2
You put so much work into these reviews. So much valuable info, but so much. Great job.

atechreviews
Great review and awesome, informative pictures, man!
I loved the style of your previous reviews, but this one’s great too It is super easy to follow and understand. Excellent work.
Ali Hasan Hamim
100+ Head-Fier
Pros: Fun and engaging V-shaped tuning
Punchy and meaty mid-bass
A DSP Cable with proper DAC
Weighty mids
Sparkly and energetic treble
Decent imaging
Practical carrying pouch
Great microphone quality
Punchy and meaty mid-bass
A DSP Cable with proper DAC
Weighty mids
Sparkly and energetic treble
Decent imaging
Practical carrying pouch
Great microphone quality
Cons: Laid back mids
Struggles with busy tracks
Stock ear tips aren’t the best pairing
Struggles with busy tracks
Stock ear tips aren’t the best pairing
Disclaimer:
Firstly, I would like to thank HIDIZS for sending this review unit, and also to my friends at Sonic Mantra for giving me the opportunity to test it out. This review reflects my honest opinions. I did not get influenced or paid by anyone for this review.
Introduction:
The Hidizs ST2 Pro Nebula is their first effort at a DSP IEM which in my opinion, they nailed it. This next gen DSP features a proper Dac chip that has enough power to drive most IEMs. The IEM itself is a variation of the Harman 2019 target with elevated mid-bass. Currently they are going for $39 on super early bird and $49 for early bird. This will launch at Kickstarter on 19th December.
Here is the Kickstarter purchase link if you’re interested.

Package Contents:
- The earpieces
- 2 core braided DSP Cable
- Three pairs of white normal bore ear tips
- A leather carrying pouch
- User manual
Unboxing experience is simple with the drop style unbox. After opening you’ll be greeted with the ear pieces on top. Removing the top cover will unveil the leather carrying pouch inside which is the DSP cable and ear tips.
Build and Design:


The Hidizs ST2 Nebula’s shells are made of resin which makes it relatively lightweight. The water drop style faceplate has a metal plate at the center with HIDIZS logo. The shell is fully transparent which allows us to see the driver and the cabling through the resin easily. Aesthetically, the transparent shell does make it quite the looker. The DSP Cable is braided and has two tone color for each cores. With the white/transparent one the cable is grey color with light and slightly dark tone on the cores. It has a mic attached to the right side. The USB type-C jack is metal built with transparent glass/plastic on each flat side to make the DAC circuit see through which looks very nice.
Fit and Comfort:


The shells are medium sized and lightweight making them very comfortable to wear. The nozzle angle could’ve been a bit more aggressive which I would’ve liked better, but that’s just me. It gives a snug fit which is comfortable for long periods. But the isolation is nothing amazing with this one. The cable is very soft and lightweight but is a bit tricky to handle as it tangles on its own.
ST2 Pro DSP Cable:
This next gen DSP cable is the actual break through from the previously seen DSP’s which are basically fancy EQ. This ST2 Pro DSP Cable boasts an ES9281AC PRO chip that supports native DSD playback from DSD64 to DSD128. It also supports 8x MQA Decoding and PCM playback up to 32bit/384kHz. The DSP Cable can deliver up to 70mW power at 32 ohms, which is enough for many IEMs. The sound of the DSP cable is not neutral per say. It has a fun sound with mid-bass emphasis. The tuning is again close to 2019 Harman Curve.


The battery drain on phones with the DSP cable is noticeable. It does drain the battery a bit fast compared to any other DSP I have tried but it is comparable to battery drain of budget dongle DACs like ddHIFI TC44Pro E2. The attached microphone is one of the best integrated mic with IEM cables. It's loud and clear, doesn't add any artificial tone unlike other mics.
Sound Quality:
As mentioned earlier, it follows the 2019 Harman curve with a mid-bass boost. I found the IEM to sound best with DUNU Candy ear tips. So, the sound evaluation will be based on the mentioned ear tip and stock DSP Cable:
- Bass:
The bass performance is remarkable here. The sub-bass has good presence and goes deep. The rumble is adequate making the lows sound powerful. The extension is good as well making it sound spacious. The mid-bass has more focus than sub-bass. Its full bodied and punchy along with the powerful tactile feedback that makes it sound prominent. The texture is decent giving an engaging experience with the mid-bass. In some occasions the mid-bass does sound overpowering over both sub-bass and mid-range. The hard hitting mid-bass even influences bass guitars and makes them as much tactile even if they are supposed to sound softer. The rumbles with the bass notes also feels powerful. In some occasions, the mid-bass does sound ‘in your face’ type if you’re listening with high volume. Ultra low frequencies don’t have that quirk which would’ve made it a bass-head level IEM. The separation in the lows is not the best, but tip rolling can help with that.
- Mid-range:
The mid-range leans towards the warm side. The powerful mid-bass causes the mid-range to sound fuller with good amount of note-weight. But due to the recessed mid-range the vocals sound soft and smooth. Male vocals lean toward warm tone with thick note weight. They sound rich and smooth with the mix. Female vocals on the other hand sound energetic and crispier than male vocals. The upper mid-range energy gives the female vocals added focus compared to male vocals. Instruments sound both smooth and energetic where needed without going of the track with timbre. The electric guitar energy has a satisfying bite to it. Even if the mid-range is not the main focus here, it still delivers good performance within the mix.
- Treble:
The treble sounds energetic and sparkly. The control with the sparkles are nice as it doesn’t exhibit any kind of harshness whatsoever. It renders the splashy cymbal and snare hits in an enjoyable way keeping the energy to it without exhibiting any sibilance even in sibilance drowned tracks. It is sparkly, detailed, and energetic while keeping any kind off harshness in check which won’t even bother treble sensitive people. Like I said, lower treble is detailed, well extended and energetic with a touch of fun. I won’t say it is fully transparent with the rendering but is close enough. The added color does make it sound more engaging and goes well with the rest of the sound regions pretty good. Upper treble is also nice with the sparkles and adequate amount of air. It has a fun sounding yet safe treble which doesn’t go over the top, but definitely is focused as much as the lows.
- Technical Performance:
The technical performance is a mixed bag for me. It shows enough technical prowess where it doesn’t sound lackluster, but sometimes it seems to struggle as well. Let’s break it down.
The sound stage is at the same time impressive and lacking. It has a rounded stage which expands equally in every side. That makes the sound cues coming from the front more noticeable. But it lacks in stage width where it could’ve benefited from a bit more refined layering. The imaging on the other hand, is pretty good. It can locate instruments pretty well in the mix but that’s not exactly precise. Instrument separation, even different sound region separation lacks a bit. Tip rolling can help a bit but that can’t be called a solution. While detail retrieval is decent, the not so great separation holds back its potential with macro and micro detail retrieval. The only complaints with technical performance would be with the stage layering and separation.

Source and Tip-rolling:
The Hidizs ST2 Pro Nebula comes with its own source being a DSP IEM. The impressive DSP or rather DAC implemented cable does pair pretty good with the IEM. With external source the IEM loses a bit of focus on mid-range whereas the ST2 Pro cable fixes that giving the needed focus. It also makes it sound a bit quirky which influences the whole frequency range. The IEM is good to go with the DSP cable or any other source which isn’t overly analytic.

Conclusion:
The Hidizs ST2 Pro Nebula provides an incredible value for its price. The IEM itself has an inoffensive V-shaped sound which is very fun and engaging. The ST2 Pro DSP cable can perform as a full-fledged source where you won’t need anything else other than your phone. The integrated DAC supports hi-res playback including DSD and MQA decoding. Not to mention the quality mic attached to it. Overall, it’s a brilliant package from Hidizs which became my favorite DSP IEM and cable. Both the Hidizs ST2 Nebula and ST2 Pro cable is highly recommended for those looking for portability without sacrificing quality audio.
Attachments
Last edited:
Ceeluh7
500+ Head-Fier
Pros: -Great pouch
-Very portable, easy to manage when out and about
-8xMQA, Native 128DSD, 32bit/384khz
-ES9281AC Pro dac chip is great to see in a device like this
-70mW of power is way more than enough for most iems
-The cable is really great with most earphones I pair it with
-Just a nice cable altogether
-Fun sound out of the earphones. With or without the cable
-Deep, hard-hitting bass
-Sparkly treble
-Detail Retrieval
-Imaging
-Very portable, easy to manage when out and about
-8xMQA, Native 128DSD, 32bit/384khz
-ES9281AC Pro dac chip is great to see in a device like this
-70mW of power is way more than enough for most iems
-The cable is really great with most earphones I pair it with
-Just a nice cable altogether
-Fun sound out of the earphones. With or without the cable
-Deep, hard-hitting bass
-Sparkly treble
-Detail Retrieval
-Imaging
Cons: -The treble can come across a bit artificial sounding
-Earphone build isn’t the best we’ve seen
-Stock eartips do not do this set justice
-Other 2-pin sets feel ever-so-slightly looser than normal
-Earphone build isn’t the best we’ve seen
-Stock eartips do not do this set justice
-Other 2-pin sets feel ever-so-slightly looser than normal
Hidizs ST2 Pro Nebula Review

Full Review HERE

Hidizs ST2 Pro Nebula Review
Intro
Hello, this review and feature covers the Hidizs ST2 Pro Nebula (ST2P for review purposes) from the audio brand Hidizs Audio. Hidizs is a brand who are usually somewhere around the front lines of innovation and this new budget DSP cable and earphones certainly promises a large uptick in fidelity in a very portable and mobile form. Now, the ST2P is actually a Kickstarter project which debuts on December 19th, 2024, and so it will be very good to get your order in when deadlines allow. One thing I notice about most Hidizs products is that they usually improve upon different tech that’s already on the market, and they usually do so at a competitive cost for the consumer. The ST2P seems primed to be one of those products. Made entirely for those who don’t have the funds to purchase some top-of-the-line dongle dac, dap, dac/amp etc. or for those who want a very portable and convenient way to listen to high resolution music.Hidizs
Ya know, I’ve spent a great deal of time with Hidizs products over the years. Coincidentally, I’ve also spent a lot of money on some of those products (relatively speaking). One thing I take away from those products is that Hidizs does what it takes to stay relevant, and they do that by crafting with quality and pricing in mind. I’ve performed quite a few reviews covering this brand and I can tell you that I’ve yet to run into a bad product. This is a brand which doesn’t shy away from some heavy R&D and usually brings to market devices which are complete and ready for the market. This is no small thing. Too often products are rushed to market and the end result shows. At any rate, I am very curious about this latest ST2 Pro Nebula.DSP cables
As I said, Hidizs is usually at the forefront of new tech or at least at the starting line with most technology. It appears that Hidizs realized that they needed to get in on the DSP cable bandwagon as they are certainly not the 1st brand who brought one to market. In fact, by now there have been quite a few brands who have dipped their toes into this portable form of audio. I would say that the idea of DSP cables was birthed “post” the exclusion of 3.5 single ended ports in smartphones (what a terrible day for so many audio fans) in favor of Bluetooth devices. Which of course left those fans of wired audio in the dark. Obviously, Samsung and Apple had a remedy as they began providing earphones with DSP cables with all of their devices. However, the rest of the purchasing public was forced to either go the popular Bluetooth route, or purchase a dap (digital audio player), dac/amp, or dongle dac. Of course, they could always go with an older phone, which has issues of its own. It was a dilemma of sorts. At any rate, it wasn’t long until you began seeing more and more DSP chipped cables hit the market. In truth, they’ve gotten pretty darn good folks. As the hobby does, it adapts, and it overcomes. I must admit that DSP cables aren’t my first choice as an audio source, but I cannot sit here and lie and say that I’m not completely impressed by what a tiny dac/amp inside of a tiny usb-c housing can afford the listener. Good sound is good sound, no matter where you are getting it from.Ready
That all said, I am 100% ready to check out the ST2 Pro Nebula. Both the earphones as well as the cable that comes with it. In a way this is a two-part review as both the earphones and the cable each combine to form the package. I should also state that Hidizs did provide to me an extra MMCX cable which I will also feature in this review. So, without further ado, the Hidizs ST2 Pro Nebula everyone…Check out some of my other Hidizs Reviews:
–MM2 Mermaid–MS5
–MS3
–MP145
–MS1 Galaxy
–S9 Pro Plus
–S8 Pro
–SD2
–MP143
Non-Affiliated Purchasing Links:
–Kickstarter Link (Super Early Bird: $39) Beginning December 19thDisclaimer:
I received the Hidizs ST2 Pro Nebula from Hidizs as a review sample and in exchange I will conduct a full review and feature at Mobileaudiophile.com. I have not received any payment or any other form of compensation for this review. This set is a review sample iem. Hidizs has not requested to pre-read any review and doesn’t have any control over “what” or “when” anything gets published to mobileaudiophile.com. All thoughts within this review are my own, though please take note that I will always have my own biases. This is impossible to get around. I try to be as objective as my subjective self can be, but this is an opinion piece folks. Thank you to Hidizs and thanks for reading.
Gear used for testing
-Samsung Galaxy Z Fold 5-LG V60
-Too many iems to name here

Packaging / Accessories
Unboxing
The Hidizs ST2 Pro Nebula arrived at my home in a small black box that features a picture of the ST2P on the front cover. You get the ESS logo, DSD, MQA, and the Hi-Res Audio logo as well. All indicators of the pedigree of this set. On the back are some specs etc. Once you open the box, you’ll see the ST2P staring right back at you in all of their splendor chilling inside of cardboard/foam cutouts. Pull that layer off and you will see the very nice leather pouch which comes packaged along with the 2-pin type-c cable, the eartips, as well as a usb-a to usb-c adapter and the manual/warranty card. Of course, there really isn’t much more to report as one would expect for this type of product. However, it’s not a bad package by any means.
Eartips

Hidizs added to the accessory haul three sets of eartips (S, M, L). The eartips are a white silicone tip with a semi-narrow bore, flimsy flange, and semi-rigid stem. Now, this is one very small point of contention for me as I really feel that the eartips provided do not do the ST2P justice at all. Not that they are bad tips per se, but they simply don’t provide me with the best seal and if I’m being honest, they don’t provide the ST2P with the best sonics. Again, not horrible tips but for me they just didn’t work. Of course, this is an issue with 85% of earphones that I receive. For whatever reason eartips are more of an afterthought anymore whereas they should be a well thought out and important piece of the audio chain. No doubt about it. At any rate, I went with some no name tips which resemble the KBear 07’s in every way except the color. They are semi-wide bore tips, firm flange, firm stem, and they really do seal well. Basically, they’re KBear 07’s, so if you are wondering what is best to use, I would advise to at least start with a set similar to these. I also used a set of Final Audio E-Tips as well that sounded great but the comfort from the 07 clones was too good to pass up.
Pouch

One of the bright spots of the unboxing is the leather pouch that comes with it. I rarely use carrying cases, but I’m a sucker for a good leather pouch and this one is quite great. Actually, this is the same leather pouch that we’ve seen packaged with a few other Hidizs sets. Like the MS3, MP145 & MP143. I liked this pouch in those reviews, and I like it now. Really, it’s a perfect size for my front pocket and that is the most important thing for me. I realize I’m speaking on a pouch right now and very few of you care but it’s the little things for this reviewer. I love a good pouch. At any rate, the leather is so soft that it’s almost satisfying for me just to hold the thing. It also has a pinch-open and snap-close top with two small strips of sheet metal. I don’t really have anything more to say about it. It’s just a nice accessory.


The MMCX Version of the ST2 Pro Cable attached to the Fiio FD5
DSP Cable
Build Quality
The cable provided with the ST2P is a very fine and highly capable blue/black cable. To be exact it is a 2-pin high purity OFC (oxygen-free copper) copper cable with a fabric outer insulation coming in a nice twist pattern and a type-c termination. It is a 4-wire 260-core cable. Not very thick, very pliable, easy to use, not microphonic. Physically it is extremely flexible and not rigid in the least. This cable won’t add any extra weight to your ears or pull on your earphones, at all. Now, Hidizs provided me with both the 2-pin that comes with the ST2 Pro Nebula package as well as an additional mmcx cable (gray cable in pictures) which is the exact cable to be used with other iems. The cable which came with the ST2P is a blue/black colored cable and the look is flat out cool. Hidizs did a nice job selecting the materials used. Of course, these cables are DSP (digital signal processor) type-c cables to be used with any type c Android, Windows, Mac OS, IOS, or Harmony devices. However, I’ll get into that in a bit. The cables also have a working mic with a multifunction button controller. The actual build is impressive enough. Certainly, better than any other DSP cables that I have on hand.Only issue
The only partial downside to the cable is the fact that some 2-pin iems feel somewhat not as tight as they ought to. I’m not saying they are loose or falling off, but they simply aren’t as tight as one would expect all the time. I don’t feel this is a hard “con”, but I did list it in my “Pros & Cons” at the beginning of this review. Again, I have yet to have any issues with it and never once in the entire time I’ve used this cable has an iem fallen off, but it is something to simply mention, for full disclosure.Cable Features

One cool thing about DSP cables is the fact that they come with a digital signal processor or a dac chip which enables them to be able to process the signal ultimately providing the listener with a cool and portable way to listen to their music. Having said that, these DSP cables are most certainly not created equal. Just like any source device which uses different dac chips and circuitry, so do these cables. In the case of the ST2P, Hidizs decided upon an actual very high quality dac chip which was somewhat surprising to me when I first found out. That chip is actually the ES9281AC Pro which is one of the better small devices dac chips, better than middle of the road and not one you’d usually find in a cable like this. Well, at least I haven’t seen any with this particular chip inside. I fact, this chip is used inside of some amazing dongle dacs like the Questyle M15 and the Earmen Colibri, Hiby DH80S (among many others) for example. Basically, it is a very high quality usb SOC style chip and I’m very glad to see it implemented within the ST2P cables. You will at least know that you are getting a chip capable of hi-res audio made by some of the best in the business.
Driving power
One great thing to see inside of a cable like this is the ability to swap earphones. However, not every earphone is as sensitive as others. There are some slightly harder to drive sets which require a bit more amplitude to bring them to proper fidelity. So, how nice it was to see that the ST2P has a max output power (driving power) of 70mW at 32 ohms. For those who don’t know, this is much higher than you usually see with these cables. Furthermore, every single iem that I placed on these cables was easily driven to not just good volume, but also to good dynamics, good dynamic range, tight transients in respect to how they usually sound etc. Maybe some planars will want more juice but most sets are driven very well with this cable. That said, I have a few planars which sounded great on the ST2P cable. Obviously, planars have a seething need for huge amping but even the Hidizs MP143 was able to be driven pretty well. The Letshuoer S12 Pro as well, Kiwi Ears Melody, KZ PRX, Raptgo Hook-X, and many more. I don’t want this to get out of hand because a better source will obviously do better. Still, for a cable of this type to be able to give really nice fidelity is a sweet thing. Additional Features
Another capability of the ES9281AC Pro is that you can get a whopping 8x MQA unfolding which is nice for those who have MQA tracks. You can get up to DSD 128 as well. Folks, you simply cannot get this kind of audio luxury from DSP cables all the time. Beyond MQA and DSD the ST2P cable can decode sample rates up to 32bit/384khz PCM. It also has an inbuilt microphone which is actually quite good by the way. Very natural sounding for a microphone such as this. The cable connector also has a red and blue sample rate indicator which will tell you when you are playing 44.1-48 kHz PCM, 32-384 kHz, and native DSD 64/128. This cable also has a HyperStreamII Quad Dac Dac ™ Architecture to help the chip with processing. Really a high-quality cable with plenty of features not usually seen in these types of cables.
Build / Design / Internals / Fit
Build Quality (iem)
Now we will cover the actual earphones themselves. So, the build quality is probably not top of the line for this price point, but you have to figure in the package as a whole when looking at the final price. In all honesty, the ST2P are made fairly well, just nothing which will blow your mind. Made entirely out of a resin material, like hard plastic and made with a typical universal iem style. The resin is fully transparent too. The nozzle is about medium length, or average length I’d say, and the nozzle tip is roughly about 6mm in width. The build isn’t bad, but we’ve simply seen some amazing builds of late at very low prices. Again, take into account the fact that you can put any set of earphones on this cable. However, the ST2P is still built rugged enough. Again, they are made with hard resin material and should be hardy enough for working out, running, working around the house, at the market, etc. Those are some of the use cases which the ST2P will likely be most used for.
Design
As far as the actual design of the ST2P, I have to say they did a nice job. Like I said earlier, it’s a fully transparent housing which comes in two different colorways. Those are either “white transparent” or “black transparent”. Obviously, my set is the black transparent, and I really dig the look of these. It’s a very simple design yet tasteful. Very much a minimalist look. I look that the faceplates feature a golden logo on the center which is a nice touch for a set like this. They just look cool. Really a nice job by Hidizs for not going too far or too flashy with the design, which is something I know these brands are tempted to do at times.Internals
Inside of the ST2P housing Hidizs decided upon a 10mm PU+PEEK composite dual magnetic dynamic driver to put to use inside of the ST2P. It’s a solid setup for a budget set. No doubt about it. I don’t hear a bunch of undue distortions or oddities in the sound. It’s a solid driver, at least to my ears.Fit / Comfort
For me, the ST2P fits like a glove. Of course, I rarely have iems that don’t fit my ears well. Perhaps I’m some sort of an oddity but I simply just don’t have issues with fit most of the time. I say that to also speak on the fact that I cannot tell you if this set is going to fit your ears. I wish I could. The truth is, it is an extremely light earphone, you won’t feel them once you’ve achieved a seal. Very little pressure on the inner ear. Really the ST2P is a very comfortable iem and I had zero issues in fit and comfort. I’m sorry if this doesn’t help you at all. I could also add that, you shouldn’t get any undue condensation build up using this set. Let’s say you are working out, running etc. So that’s a plus I suppose. At any rate, really light, not too large, nozzle fits fine (not too deep), and just an overall comfortable earphone.
Drivability
Output Power
Okay, I will be very short here because the cable is really the determining factor on how much power any of you are giving the ST2P. I suppose you could take them off of the cable and use it with another cable though. At which point this section may make some sense. However, let me just knock it all out in a quick paragraph because this review is really intended for the earphones to be used with the included DSP cable. So, this set is flat out sensitive. Very sensitive. For instance, the ST2P has an impedance of 32 ohms and a sensitivity of 108 db’s, which is pretty darn sensitive folks. Basically, you can drive this set with most any source. In regard to the included DSP cable the ST2P gets huge amounts of headroom and can reach ear splitting levels if need be. The 70mW provided from the DSP chip within the cable is honestly overkill but works awesomely for this set of earphones.Source Tonality
Again, this section is only for if you want to take the ST2P off of the included cable for use with another cable. So, the ST2P is closer to neutral/bright in tonal coloration and so I do advise a slightly warmer source device first. Actually, just don’t use a “bright” source. I’d try something anywhere from neutral, warm/neutral, to warm. You simply don’t want to exaggerate the bright upper-mid/ lower treble range any more than it already is emphasized. Still, at the end of the day, just keep this set in the included cable. Together they sound great. Hidizs did the work and paired these two nicely. A very harman-ish sound. I’ll talk about that more in the next section as best I can.DSP Cable Tonal Pairing
Now, as far as pairing the DSP cable with “other” earphones (which I did a lot by the way), I would really try to use slightly warmer sounding sets. The ES9281AC Pro is a slightly more energetic sounding dac chip with the way it was implemented in this cable. I’m telling you, pair with a warm/neutral to warm sounding set and you’ll be overly impressed. For instance, the warm/neutral BASN BMaster5 is warm/neutral, and I used it with the MMCX DSP cable that Hidizs provided me. Oh, my folks! It sounds so great! The tonalities converge wonderfully. Again, this cable is tuned a hint on the brighter side and so brighter sets will certainly come across… well… bright. Just keep that in mind. Also, this is not an across-the-board thing. For instance, I tested the 2-pin cable with some brighter sets like the Simgot EA500LM as well as the EPZ Q5 Pro and what it provided was a much more detailed sound. Certainly, bright for some (brighter earphones) but the sound is well controlled and very clean. So, there is just a couple tidbits about the sound pairing with the DSP cable.
Sound Impressions
*Note: I want to preface this sound section with a few things. First off, I used KBear 07 tips for all critical listening. I also burned the ST2 Pro in for a couple days. If I’m being honest, I didn’t see much of a change. I also listen almost entirely with flac or better files that are stored on my devices. Lastly, I will not cover the sound portion of this review as intensely as I usually do. So much of the sound is covered by the cable as well as the earphones and so I will complete a quick summary in each 3rd of the frequency (bass, mids, treble). How does it sound?
The Hidizs ST2 Pro Nebula comes in with a definite V-shaped sound signature that emboldens and emphasizes the mid-bass as well as a certain lift within the treble region. If I were to characterize this sound in one word, I’d call it “energetic” first. However, this energy comes with a certain level of capped brightness that skews all notes crisp, well enough detailed and a solid note structure. I would usually never say this about a set which I would presume is a budget minded set without the cable attached. I don’t hear the uncontrolled and wild splash of a treble boosted budget iem using cheap drivers crafted to make a quick buck. No sir. Hidizs put some time into this iem/cable combo folks. You can hear it right away. Budget set or not, the sound is a solid bright/neutral and fun sound with sparkly and sprightly energy which serves very well those folks who enjoy this type of contoured and structured brightness. There’s just a ton of energy on tap, big macro dynamics too. Yes, there’s certainly a huge dose of heavy and deep droning bass and a fairly robust yet vibrant slam. That low-end weight is contrasted with a tinsley, semi-bright/brilliant and lively treble region. Despite those regions, like any V-shaped iem the midrange is a hair less intense and pushed back into the sound field. Nothing which takes away from my listening, but it’s a classic sounding V-shaped iem for sure. Crisp over smooth, fairly well detailed, cleaner as you work your way up the frequency and once more… energetic. So please keep this in mind when deciding about this set.Iem, or the cable?
One of the first questions that I needed answered was whether the brunt of the sound that I was hearing was coming from the iem or the cable? Well, how much bass, the brightness, the control, the highly precise sound, where was this coming from? Is it a perfect combo? So, there is most certainly a difference when I take the iems off of the included DSP cable and attach them to a 4.4 cable for example. The bass is even more pronounced, the lower mids a hair more forward, heavier in note weight, the sound a touch smoother. Just a touch. What I think we are seeing is something that I like to call “a damn fine pairing”. I think that together they sound wonderful. I mean, what is a DSP cable anyways if not the exact same thing as we hear when we plug these earphones into any other source. Two products meshing together to form a coupled sound. So, to answer my query, yes there is a mildly large difference as to how the ST2P sounds with or without the DSP cable. To be 100% honest, the iem attached to the 4.4 cable still sounds pretty darn good. Yet it is a hair different then you’ll hear attached to the DSP cable. I figured this would be the case. It’s a little bit of both. With that said, let’s take a look at this pairing within each 3rd of the mix…

Bass Region
The low-end is one which rumbles fairly deep and has some solid extension into the lowest of lows. The bass hits with some solid slam, hard surfaced, not pillowy, meaty in its weight. Yet it doesn’t come across warm, or wide in its presence. In fact, the bass is pretty tight per the quantity I would say. Especially for the price point. It’s bold, yet it’s punchy. The low-end has a crisp punch, not softened, yet also not that concrete hard thud either. Transients attack, decay, and recover quick enough to not allow the lag of harmonics to stuff up the sound field very much. These ES9281AC Pro dac chips are doing some work here because without the cable the ST2P isn’t quite as exact in its note definition. I’m not saying it’s a kilo-buck killer, but the ST2P has some nice agility whilst coming across bullish. I’d usually say it’s “tight for its size” or “clean per the quantity”. This is true here. Substantial Enough
That all said, the bass is a little baked, arid almost, not as moist in note body, perhaps a hint dry. Obviously, some tracks will tell a different tale, but I can easily hear this in the track “Take on Me” by Weezer. The kick drums are very tight, yet they’re also robust in body. There’s a definite snap on attack, a tacky edge on the initial kick at the crest of the note, while the hollow boom is substantial enough to help kick drums sound very satisfying to my ears. In truth, it’s just another way to hear them. Is it perfectly natural? Not exactly. However, still a nice sound out of this set. Again, you can hear the energy willing each note, sprucing up my music, adding a dash of intensity.Clean, Defined, Rigid
Now, extension into the sub-bass isn’t the deepest and there may be a bit of a roll-off there but nothing which is too egregious. I still have a haptic feel to many tracks and a low droning deep pitch in tracks which call for it. Tracks like “Mancey” by Andrew Bird. The bass guitar is very clean, defined, rigid in its mass and best of all, the bass doesn’t infringe on the rest of the track or mask over any other instruments. Then you look at the mid-bass which has a hair more emphasis to my ears. I hear unsullied and precise notes when needed and I hear a bulbous boom when needed too. Also, there’s no doubt that the ST2P’s bass may surprise some of you with its obvious texture to the sound. Add to that, the speed of the bass is pretty impressive as the ST2P is able to take on quicker and more complicated bass tracks pretty nicely. Really a nicely done low-end for what it is. Maybe not everyone’s favorite, but it is a skilled low-end which will fit many genres well.Midrange
As far as the midrange is concerned, it’s ever-so-slightly recessed. As with most V-shaped sound signatures the ST2P’s mids sit a hair back in the sound field, at times. Without question there are some tracks which you will call me a liar over. Some tracks sound almost up front. However, on average the midrange sits roughly on the same sound field plane as the bass while the highs sit a hair closer to the listener. Again, not every track is created equal, and you may hear something different. Nothing at all that sounds weird or out of place and the midrange has good energetic presence against the rest of the mix too. I think a lot has to do with the fact that the midrange is very clean. Separation is great, notes are more sculpted as well which helps the note presence sound more defined to the ear as notes are less meshed together. At any rate, I hear a leaner style note body in the midrange but once again, the presence is enough to give each note some density. They may be a bit lean, but they aren’t papery, or overly dry which really does help vocalists and instruments to not come across weak, frail, or artificial sounding. I go back to the energy as there is certainly some vibrance. On top of that, the mids have a lot of air and openness to their sound which greatly helps note separation, Imaging, and detail retrieval. Males & Females
Males and instruments in the lower midrange carry some level of vibrance but this area is certainly a hair smoother overall than females in the upper-mids. There is the slightest bit of warmth carried over from the bass region which helps in this regard. The upper midrange on the other hand carries more sparkle, and a healthy dose of shimmer, more energetic, and I perceive them as slightly more forward than the low-mids. This is to be expected though. With all that said, both male and female vocalists sound pretty nice for a V-shaped sounding budget set set. Honestly, I don’t feel they are lackluster at all, and vocalists usually come across pretty well highlighted against the mix. Depending on the track of course.Articulate & Transparent
Certainly, Hidizs was going for a higher energy sound in the midrange, more articulate, transparent, and they were likely wanting to craft a sound which illuminated the subtleties (details) within a track. This is exactly what I hear. Note weight is not lush, or ultra rich. The sound generally is a bit more crisp than smooth. There’s some nonabrasive crunch and solid note contour too. It’s actually a nice sounding midrange. Again, separation is really great to my ears, the sound is open and airy enough and it is rather easy to pick apart details in my music. This is definitely a set which toes the analytical line with just enough musicality. All things considered, I feel Hidizs did a nice job here. Without question the dac chip has a huge influence on the overall sound and the quality of that chip can be heard.Treble Region
The treble has some certain sparkle to it. I like to think of it as controlled brilliance as I don’t feel it ever goes over the top. Perhaps on a couple tracks the ST2P can get a hair rambunctious, but most of the time everything keeps solid control and stays bright yet not offensive to my ears. Really, I find the treble to be a standout feature of this set! Wonderfully done highs for the price and the tech. I never find them to be overbearing which is quite nice being that the sound is skewed bright. A very lucid sounding and vivacious treble that honestly doesn’t lead way to splashiness as so many sets can do when the treble is a bit more enthusiastic. Especially budget sets! I hear very solid extension helping cymbals and hi-hats to sound bodied, with some bite, some well-mannered snap, but never tizzy or splashy. I can clearly hear the cymbals on “In Bloom” by Nirvana. Never once do they sound out of tune or anything alluding to a corrupted and forced-bright treble region. Which brings me to my next point; I don’t hear any forced resolution, which is all too common. Brands will force lift their treble regions to seem more resolute, leading to better details but also a slew of other compromises. Not the ST2P. Actually, I am impressed first at what this cable can do because it does help veer other iems in similar ways. But also, I’m impressed by what this budget single DD can do. I really am. Just a very clean and pristine treble with great note definition, note body, and treble bite without the abrasiveness and sharpness which I’m so used to. Nice job Hidizs
I think one of the things you’ll find with this iem/cable pairing is that the treble exceeds what you may be expecting. Now, I’m not saying that it pinches above its price, or that it far out paces sets within its price point. But I am saying that Hidizs did a fine job in recreating this area of the spectrum. You’ll Gear very good detail retrieval which has very solid micro-dynamics picking up even the finest minutiae. Obviously, in Ultra complicated tracks you won’t get the same results being that this is a single DD. However, for a single DD at this price I still hear very good instrument separation in the treble region, and it can take on some very fast paced tracks too. Tracks like “Gone a Long Time” by Billy Strings (I always use his songs for treble output) which has layers of banjo play at fast paces. But the treble also has good tonality and timbre for a slightly brighter sound. Tracks like “Evil Twin” by Lindsey Sterling is a great example of a set which keeps great cadence, and each note sounds accounted for and rounded. For the most part. They did a good job here.Not for everyone
Having said all of those glowing words I should also add that without question not everyone wants to hear a lifted treble region. I get this and I didn’t want this section to be complete without speaking on it. Of course, there are those who only desire a warmer and more organic sounding treble. I have plenty of friends who only enjoy a rolled-off and darker treble region. In case you haven’t read any of this review, the ST2P is not that… at all. This set is not going to be kind to poorly recorded tracks as well. I know because I have heard it. When you have such a crisp and defined sound then subtle jagged and grainy or low-resolution tracks will sound as such. However, beyond those caveats, the treble is not bad at all, nice work Hidizs.

Technicalities
Detail Retrieval
As far as the technical ability of the ST2P, I feel that I’ve covered this by now. However, I will reiterate some of the points covered this far. First off, detail retrieval is fantastic on this cable/iem pairing. The two of them together really do highlight the minutiae very well in most any track. I would say that the only slight departure from that would be heavy bass tracks. Of course, the bass can and will mask over some of the subtleties in music. Of course, those are few and far in between. And also, who of you are dying to hear the details within a heavily bass focused song? That’s not something that I’d think many of you are trying to do. Perhaps also extremely complicated tracks will give this single DD a run for its money. This isn’t some five-driver hybrid with different drivers taking on only specific portions of the frequency band. This is a single DD handling it all and so obviously more congested and complicated tracks will stretch the single DD past its abilities. Also, this is a budget set so I would suggest tempering your expectations a bit. Still, I am very impressed by the transparency, resolution, and overall detail retrieval ability of the ST2P.Separation / Imaging
Just like detail retrieval, the ST2P has an uncanny ability to add “perceived” air gaps between instruments and voices. It’s a more open sounding set and therefore you do get a sense of extra space for elements of an imaginary stage to exist. Also, notes are concise on this set. You don’t have lingering harmonics plugging up the air lanes or meshing notes together. Not exactly anyways. Of course this is a majorly simplified view from my perspective, but I feel that note separation is very well accomplished on most tracks. Imaging follows suit to the tee. Actually, I find the imaging to be awesome. Every instrument has its place, and there’s nice layering at times too. Really well done.Soundstage
Now, the soundstage is about average I’d say, if not a hair above average. Certainly, the sound is open and not congested. There’s room for the music to operate and the sound does seem past my ears. Obviously, some tracks actually sound more constricted and less open sounding and those won’t always come across vast or “above average”. By-and-large the soundstage has some good width. You also have good height too and decent depth. I’d say it’s weakest point of the stage is probably depth, but not bad by any stretch of the imagination.
How do the DSP cables sound with other iems?
I should note that I used both the 2-pin and mmcx (can be purchased separately) cables on other iems and I adore the influence they gave so many of my sets. For instance, I put the Fiio FD5 on the mmcx cable and folks… I don’t want to take it off. A very nice pairing together. The bass got much tighter as it’s no longer slightly flabby as it usually is, among other notable improvements. Slightly better detail retrieval than usual, a bit crisper at the crest of notes. Stuff like that. Of course, I think I can get this result from any number of more analytical sources, but it’s nice to hear this from a simple cable attached to my phone. Oh, the Kefine Klean attached to the 2-Pin cable is another winner combo. Think of the tonality and timbre of the Klean and add even more contour to the note delivery as well as a touch of added transparency without hindering musicality too much h. The bass gets a hint tighter, yet you lose none of its authority. The midrange sounds even more open to my ears too. I feel the note weight suffers a bit, but you gain in technical ability to my ears. These two pair very well together in my opinion. Another set is the EPZ Q5 Pro which is a bright leaning iem. Most folks wouldn’t put a bright iem with a brighter leaning source, but I found that the cable doesn’t add unwanted glare. That’s the thing, it’s a very controlled and capped brilliance, neutrality without the peaks. The Q5 Pro actually sounds highly technical with really astounding detail retrieval paired with this cable. Folks, I could go on and on, but I won’t bore you. Basically, the cable fits many sets of differing tonal colorations. I’d say it improves upon many of them. 
Is it worth the asking price?
This is the real question one needs answered before plopping down their hard-earned money on a set of earphones. Now, the early bride pricing is an absolutely ridiculously low $39. If you can get on the early bird, then I would do it, pull the trigger. It is too good to pass up for those who really need a good workout set, a good work around the house set, or just a set which you want hi-resolution audio at a cheap price. It’s actually a great starter set for folks getting into the hobby too. I feel that there’s no question whatsoever if the Hidizs ST2 Pro Nebula is worth the cost of ownership. Absolutely it is. Even at the much higher price of $89 it is still a good deal as well. The reason being is that this set is a two-for-one. You have the iems which are tuned well in the first place. However, what’s even nicer is the fact that you now have a very high-quality cable which can be used with any iem ending in either a 2-pin or mmcx termination (depending on what you are getting). Or just buy the cable separately! It’s an amazing DSP cable and easily the best I’ve heard to date. In fact, I just got the Tanchjim Bunny (brand new) and the Hidizs cable far outshines the Bunny’s cable in overall DSP cable skill and fidelity.The Why…
Because you are getting a two-for-one deal which can be used in many different configurations. This is a nice benefit of this Kickstarter. Obviously, you can purchase the two (iem/cable) as a pair, or you can simply purchase the awesome cable separately. There’re many benefits to either route you’d take. Friends, this cable has the same dac chip that is used within the Questyle M15! Yes, one of the best dongle dacs on planet earth. Many others too, which is wild. The fact that it is in a DSP cable is pretty cool. To add to that, the Hidizs DSP cable also gets you way more power output than 99% of the cables on the market with 70mW per 32 ohms. When it’s all said and done you will be able to power just about all iems very well. Also, it’s simply a nice package deal in my mind. I really think you are getting a complete little in-the-go setup for highly portable purposes. The iems themselves are tuned well and I believe that Hidizs put a lot of time and work into getting the sound right here. I hear a very detailed, very clean sound that doesn’t skimp on bass. Rather, the ST2P is bass heavy. Yet it isn’t a slow and muddy bass, but instead it’s a tight, controlled and punchy bass. The mids are very transparent, energetic and the treble will pull every last detail from your music with good extension. Honestly, I wouldn’t dream of saying this set isn’t worth the money. I suppose if you have a huge collection and have zero need for a setup like this then maybe you wouldn’t want to splurge for it and a few other examples. However, yes, the ST2P is worth the cost to own it.Non-Affiliated Purchasing Links:
–Kickstarter Link (Super Early Bird: $39) Beginning December 19th

Conclusion
To conclude my full written review of the Hidizs ST2 Pro Nebula, I have to first thank the audio brand Hidizs for providing the ST2 Pro. Hidizs has always been a fantastic company to work with. They have never asked anything of me but to publish a review. Never asked to read my review first, never asked me to speak highly of their products and have always been very helpful to me. So, thank you so very much Hidizs and the people with whom I deal with at Hidizs. You know who you are… Thank you! I also thank you, the reader, for clicking the link and checking out this review. Shoot, I thank anyone who even clicks to the website. We rely so much on you all, and it means the world to us that you would stop by and spend some time. You are the reason that we are keeping the lights on, so to speak. I truly hope that you get something out of this review, and it is of some help to you.
Other Perspectives
Now that you’ve read my words on the Hidizs ST2 Pro Nebula, I do hope you’ll click other links and check out other reviews from other reviewers and audio fans. It is so important to have a good idea what you are buying folks. I mean, unless of course you are like me and you blind buy constantly. I didn’t say “Do as I do”! Seriously though, it only makes sense to hear other perspectives and learn as much as you can prior to spending your money. So, please check out other thoughts and opinions about the ST2P and hopefully you make the right decision for you. With that said, I think I’m done. Please take good care, stay as safe as possible and always… God Bless!Non-Affiliated Purchasing Link:
–Kickstarter Link (Super Early Bird: $39) Beginning December 19thcqtek
1000+ Head-Fier
Pros: Great starting price.
- Good Sabre DAC/AMP.
- Warm and smooth sound, big bass and sharp treble.
- Textile covered cable, metal finish and integrated microphone.
- DAC/AMP design allows you to see inside the circuitry.
- Integrated LED.
- Good sense of power.
- 32 bit/384 kHz PCM and native 64/128 DSD formats.
- Good Sabre DAC/AMP.
- Warm and smooth sound, big bass and sharp treble.
- Textile covered cable, metal finish and integrated microphone.
- DAC/AMP design allows you to see inside the circuitry.
- Integrated LED.
- Good sense of power.
- 32 bit/384 kHz PCM and native 64/128 DSD formats.
Cons: Fade-in effect at the start of playback.
- Extensive bass can be imposed on detail and other frequencies.
- Compact and cohesive micro detail.
- Extensive bass can be imposed on detail and other frequencies.
- Compact and cohesive micro detail.
Introduction
Hidizs is on the bandwagon of combining IEMS with a DSP cable with an integrated DAC-AMP that replaces the audio connector. With today's technology of reducing converter and amplifier devices, it is easy to combine these tasks. This is not the first model I have reviewed with this in mind. This time, it has an integrated microphone and is a more universal DAC/AMP, with 2Pin 0.78mm and MMCX terminations. As Hidizs comments, this cable was born as a response to the limitations of the Bluetooth system in terms of power, high resolution audio, better sound quality, compatibility with many more devices without the need of a Bluetooth emitter, etc. The Hidizs ST2 PRO Nebula cable has the ES9281AC PRO DAC chip, with a power of 70 mW at 32 Ω, a sensitivity of 108 dB and a very low distortion of only 0.0012 %. The advantages are obvious: higher power, zero latency, wider bandwidth (20 Hz-40 kHz), 32-bit resolution and support for PCM formats up to 384 kHz and native 64/128 DSD.
Along with this cable, capsules made of resin and aluminum alloy are supplied, incorporating a dual dynamic driver with a 10 mm PU+PEEK composite diaphragm. The IEMS have been tuned according to the H-2019 target curve for accurate audio response. They offer balanced tonality, powerful bass, rich mids and moderate high-frequency extension, meeting Hi-Res audio standards for a HiFi quality listening experience. HIDIZS liquid silicone earplugs are made of high permeability liquid silicone and feature an ergonomic design that fits perfectly in the ear canal. The custom pouch provided by HIDIZS ensures safe storage and extends the lifetime of the ST2 PRO Nebula without worry.
The Kickstarter launch date will be December 19, 2024, at 10:30 AM (EST):


Specifications


Packaging
The Hidizs ST2 PROs come in a nearly square black box measuring 114x104x38mm. On the main side you can see the Hidizs logo in the upper left corner and the ESS, DSD, MQA and Hi-Res Audio logos in the upper right corner. All this is printed with holographic ink. In the center is a realistic photo of the capsule. Below is the model name in large letters and a description in smaller letters, also in holographic ink. On the back side are the specifications of the set in several languages. Around the edges is more information, as well as a label with the model option, in this case transparent black. After opening the lid, the capsules are in a foam mold lined with black cardboard. At the top is a cloth strip so that the first layer can be removed. Underneath is a black plastic bag. The accessories are inside. At the bottom are two cards. In summary, the complete contents are as follows:
It still carries Hidizs' synthetic leather pouch instead of a zippered case, as is already the case with other, even more expensive, models that only include a set of accessories. But the USB Type-C to Type-A converter is appreciated. Good.


Construction and Design
The capsules have a semi-custom shape and are made of resin, except for the outer part and the mouthpieces, which are made of aluminum alloy. The resin is transparent, so you can see the inside, the wires and the driver. The 2-pin, 0.78 mm thick, oval-shaped connection plate is located on the bottom edge. On the edge, in silver ink, you can read “Hidizs Nebula” and the marking indicating the channel. The mouthpieces are metallic, golden and have three diameters: base (6.6 mm), central part (4.8 mm) and crown (6 mm), and an approximate height of 5.5 mm. There is a hole in the center of the inner face.
The DSP cable is constructed with four wires and 260 cores. It is composed of two braided strands with black and purple textile coating. The metal parts are dark gray and made of aluminum alloy (DAC/AMP sleeve, splitter piece, cylindrical microphone container and button). The DAC/AMP case is oval, flat and has windows through which you can see inside the circuitry. The top face reads MQA on the end opposite the USB Type-C connector. On this side there are several LEDs inside that allow to generate various colors. On the opposite side you can see the ES9281AC PRO chip. Resin has also been used for the transparent parts of this connector. The cable has over-ear guides thanks to a transparent semi-rigid sheath. The connector sleeve is made of slightly angled transparent plastic. The letters indicating the channel are embossed and almost imperceptible. The cable has a branded Velcro strap.
The design of the capsules is quite conventional, with a transparent resin, and the difference is in the external aluminum alloy plate on which the brand and its logo are displayed. On the other hand, I like that the cable has a textile covering that gives it a little more resistance, comfort and softness. The metal parts enhance the look of the DAC/AMP cable, as do the transparent windows that allow you to see inside the circuitry. Other details are the colored LEDs, the USB adapter and the cylinder with microphone and button, which make the product an all-in-one device to replace any Bluetooth system. The next step should be a background noise suppression system for the microphone.


Adjustment and Ergonomics
The most significant thing about the capsules is their low weight of only 7 grams. The semi-custom shape makes for a great fit, but the slightly thicker mouthpieces and the angle to the ear canal can make it difficult to choose the right tips. I have tried my large foam-filled tips with no problems. However, I have found that the sound profile calls for tips with a wider channel to gain clarity and lighten the bass. For this I have used ultra large blue silicone tips, with low profile and large inner core. A good seal is achieved, although the isolation level is not so high. The set is very comfortable, but with these silicone tips the fit can be a bit more critical, as small variations in position can alter the bass response. It is not the fault of the model, but it is true that with my big tips filled with homemade foam, I get a very high bass boost that alters the natural response of the set in an undesirable way. I have looked for alternatives like the Tangzu Tang Sancai Narrow Bore or the black Penon Liqueur Silicone Eartips, but the ones that have worked best for me are these, much cheaper (blue color) and all in extra large size.
https://es.aliexpress.com/item/1005004615505310.html


Sound
Profile
The Hidizs ST2 Pro are a cable-integrated DAC/AMP assembly plus IEMS with a classic V-profile. According to the website, their profile is aligned with the H-2019 target audience. In my opinion, the ST2 Pro's enhance more mid bass and less sub bass. It is also more noticeable in V, with a more sunken midrange and a somewhat steeper rise towards the treble. Then there is a slight area of control in the first treble and an extension that pales in the air area.
Overall, the set is somewhat more emphasized in the bass, with that wide curve in the low area. That's why I've looked for some tips to lower the lower zone and favor the clarity of the whole.

Bass
Bass presence can be noticeable with some tips, but it is an easily correctable problem. I have used low-profile, wide-channel tips to promote separation, clarity and transparency. In this way, the bass does not appear saturated or overly boomy. They offer a clear sense of texture and low-medium speed. They have a moderately compact punch with good retrieval. The bass is rounded, with a sub-bass that is neither too pronounced nor too deep. The low-mid bass is the protagonist, feeling powerful and wide. It has plenty of volume and occupies considerable space, almost with a tendency to overpower.
In the very low frequency pure tone test, the limited emphasis on the sub-bass is noticeable. The audible lower note is barely perceptible, both aurally and sensorially. This detracts from its depth and accentuates its more physical character, centered at 60 Hz. As frequencies rise, the bass becomes more powerful, with a subtle color and wave-like appearance. In reality, this translates into a bass with a rough surface, expansive, powerful and extended, more noticeable than dark and physically powerful, with an obvious and forceful punch.
In the dirty, unfiltered bass test, it is noticeable that the lightness of the sub-bass brings a bit more color than sensory physicality to the sound. In any case, control is better than expected despite the somewhat more conventional sonority of its V-profile. The level of resolution is somewhat limited, although it does its job well in following the bass lines. Its sound is rounder and less defined, which gives a feeling of powerful bass, although relatively simple and not too tight.


Mids
The midrange starts warm and with some strength marked by the extension of the bass. This gives it some physicality in the lower mids and a more powerful base. The rapid descent into V makes the male voices thinner. The sharper they are, the more remote they feel. There is that sense of central hollowness that characterizes this profile. However, the instruments are well represented and are perceived whole and full.
The level of resolution is still on the soft side, appearing more rounded, with a blunt profile, bringing a rather relaxed sense of musicality and with a visible level of macro detail. The central micro detail is perceived as compacted, very attached to the surface, implying a medium level of layering and not too much depth. This micro detail is intuited, but it is not defined in a particular way, but is part of a somewhat thicker and more cohesive line.
The female voices are closer, although their base is not as marked; it is somewhat the reverse of the male voices. However, they are also perceived as warm and round, without too many nuances and with a soft aspect that limits sibilance.
In summary, the mids are musically pleasing, somewhat depressed in their center, cohesive, without too much depth, but remarkably resolved at the macro level.


Treble
The treble begins with a high point, after a slight zone of control, and a second sparkle appears that brings vivacity and a somewhat sharp extension. The level of refinement is medium, relatively pleasant, not too marked, but with a more incisive edge at times. There is a great deal of energy, though it feels somewhat limited in the air zone, already showing drier and more compact. But, although that energy is not predominant in the mix, it is so that the whole does not appear dull, dark or dull. The upper zone has its own entity and shows that it exists on its own and not as a mere accompaniment to the whole. In this way, both the high notes themselves and their harmonic contribution benefit the ensemble.


Soundstage, Separation
What strikes me most about the sound of the ST2 Pro is the volume of the bass. This feature enhances the sense of spaciousness and extension of the soundstage. On the other hand, the layering is simply good, with somewhat cohesive and compact mids. Details are perceived on the surface, while smaller details in the background come closer to it and connect, losing some ability to describe themselves with more rigor and definition.
The scene has good laterality, a level of closeness of the volume more noticeable than the depth itself, and an adequate height. The image is eminently frontal, connected, harmonious and conjunctive, without too much sensation of individuality. In this way, a warm, musical, melodious and soft sensation prevails, which moves away from any forced over-definition. The result is a fairly natural level of separation, with a sense of luminosity, transparency and clarity sufficient to prevent the whole from becoming thick, dark or overly nuanced. I don't miss light, brightness or more transparency. It does lack a little more layering, layer generation and a more evident background.


Comparisons
KBEAR Robin
I like to compare IEMS with similar profiles. Although, in this case, it would have been more appropriate to make a comparison with the INTUAURA Reference 2019, the other IEMS that have a cable with a DAC/AMP. In fact, the Reference 2019 have a DSP that alters the original sound of the IEMS and fixes it to the Reference H2019. For their part, the ST2 Pro have a DSP DAC/AMP cable. The first difference is that both claim to be based on the H2019 curve. Who is closer to the H2019 curve? Judge for yourselves.

My real comparison will be against the KBEAR Robin, an IEMS that are somewhat cheaper than the final price of the Hidizs ST2 Pro set (estimated at $89). Both have a similar capsule, more classic and semi-custom in the Robin. As usual, KBEAR includes a zippered case and two sets of earplugs, though the cable is pretty basic. The Hidizs cable, excluding the DAC/AMP, has a better finish. However, Hidizs only includes a set of tips and a faux-leather pouch.
From an ergonomic standpoint, there should be many similarities, but I find the Robin's fit better and tighter.
As a dongle to play the KBEAR Robin I used the Hidizs SD2.
The Robins have a V profile with a W tendency. They have more sub-bass enhancement and a double peak in the upper mids and first treble.
The similarity in bass is high, as can be seen in the frequency response of both IEMS. The difference lies in the greater presence of sub-bass in the Robins. The bass is large and voluminous in both models. They both have that slightly slower bass style with a longer recovery. It seems darker in the Hidizs, but has more impact and punch in the Robins.
The midrange is also very similar, with a similar transition from bass to midrange, as well as the same valley. Although the Hidizs are a bit darker, I find the male vocals crisper and better defined on the ST2 Pros. The upper mids have more overall energy in the Hidizs, despite that 2 kHz peak in the Robins. This is noticeable in that the ST2 Pro model is subtly more sibilant. However, female vocals seem to have a bit more prominence in the Robins, while there is a sense of overall darkness in the Hidizs, although you could also call it softness.
In the upper range, the highs of the Robins are somewhat softer and less bright. In contrast, I find the treble of the Hidizs to be more natural, distinct, bright, crisp, and realistic. They also have better extension, air and sparkle.
The Robins have a bit more definition, especially in the midrange, with a bit more clarity. The Hidizs are smoother, warmer and more mellow. The greater sense of depth and closer mids make the Robin's soundstage seem a bit larger.

Conclusion
I think Hidizs has joined the new trend of USB DSP cables with integrated DAC/AMP. As smartphones move away from supplying 3.5mm audio output, this new set will become more relevant, especially if the integrated DAC/AMP is as adequate as the ES9281AC PRO. The cable includes microphone and a control button, so it is all-in-one and can be used with any mobile device. The cable can be purchased individually with 2-pin 0.78mm or MMCX interface and is compatible with any IEM on the market that incorporates these connection interfaces.
In this review, the cable is accompanied by IEMS with a V-profile. These are very lightweight capsules, with a dual dynamic driver with a 10mm PU+PEEK composite diaphragm. Their sound is characterized by punchy bass, warm and smooth mids, and bright and energetic highs. The starting price has been set at $39, and on the second pass it will be $49. For that price, the set is excellent.


Sources Used During the Analysis



Purchase Link

You can read the full review in Spanish here

Hidizs is on the bandwagon of combining IEMS with a DSP cable with an integrated DAC-AMP that replaces the audio connector. With today's technology of reducing converter and amplifier devices, it is easy to combine these tasks. This is not the first model I have reviewed with this in mind. This time, it has an integrated microphone and is a more universal DAC/AMP, with 2Pin 0.78mm and MMCX terminations. As Hidizs comments, this cable was born as a response to the limitations of the Bluetooth system in terms of power, high resolution audio, better sound quality, compatibility with many more devices without the need of a Bluetooth emitter, etc. The Hidizs ST2 PRO Nebula cable has the ES9281AC PRO DAC chip, with a power of 70 mW at 32 Ω, a sensitivity of 108 dB and a very low distortion of only 0.0012 %. The advantages are obvious: higher power, zero latency, wider bandwidth (20 Hz-40 kHz), 32-bit resolution and support for PCM formats up to 384 kHz and native 64/128 DSD.
Along with this cable, capsules made of resin and aluminum alloy are supplied, incorporating a dual dynamic driver with a 10 mm PU+PEEK composite diaphragm. The IEMS have been tuned according to the H-2019 target curve for accurate audio response. They offer balanced tonality, powerful bass, rich mids and moderate high-frequency extension, meeting Hi-Res audio standards for a HiFi quality listening experience. HIDIZS liquid silicone earplugs are made of high permeability liquid silicone and feature an ergonomic design that fits perfectly in the ear canal. The custom pouch provided by HIDIZS ensures safe storage and extends the lifetime of the ST2 PRO Nebula without worry.
The Kickstarter launch date will be December 19, 2024, at 10:30 AM (EST):
- ST2 PRO Nebula (Super Early Bird): $39.00 (limited to 500 units).
- ST2 PRO Nebula (Early Bird): $49.00.
- ST2 PRO Nebula USB-C DSP 0.78mm 2-pin/MMCX Headphone Cable (Early Bird): $36.00


Specifications
- Driver Type: Dual dynamic with 10mm PU+PEEK composite diaphragm.
- Frequency Response: 20Hz-40kHz
- Sensitivity: 108dB
- Impedance: 32Ω
- IEM design: resin + aluminum alloy engraving.
- Connector cable: USB Type-C.
- IEMS capsule connection type: 2Pin 0.78mm.
- Cable connection type: Choice of 2Pin 0.78mm/MMCX.
- Weight: 7 grams approx. (excluding headphone cable).
- Cable weight: 16 grams approx.
- Cable color: Silver-Gray/Black-Blue.
- IEMS color: Transparent white/transparent black.
- Cable DAC: ES9281AC PRO
- Chip Architecture: HyperStream®II QUAD DACTM Architecture
- Resolution: 32-bit.
- Sampling Rate: PCM 32-bit/384 kHz. Native DSD 64/128.
- MQA support.
- Distortion: 0.0012%.
- SNR: 118 dB.
- DNR: 122 dB.
- Separation: 63 dB.
- Output power: Up to 70mW+70mW at 32Ω.
- Plug type: USB-C (Type-C/ USB Type-C) (Only compatible with iPhone 15 and later models) (Compatible with 99% of devices with USB-C output port).
- DAC case material: Aluminum alloy + transparent resin.
- Cable core material: High purity oxygen-free copper.
- Cable splitter piece: Aluminum alloy.
- Cable sheathing: Textile yarn.
- Cable core specifications: 4 Wires 260 Cores.
- Diameter: 4mm.
- Length: 1.2m.


Packaging
The Hidizs ST2 PROs come in a nearly square black box measuring 114x104x38mm. On the main side you can see the Hidizs logo in the upper left corner and the ESS, DSD, MQA and Hi-Res Audio logos in the upper right corner. All this is printed with holographic ink. In the center is a realistic photo of the capsule. Below is the model name in large letters and a description in smaller letters, also in holographic ink. On the back side are the specifications of the set in several languages. Around the edges is more information, as well as a label with the model option, in this case transparent black. After opening the lid, the capsules are in a foam mold lined with black cardboard. At the top is a cloth strip so that the first layer can be removed. Underneath is a black plastic bag. The accessories are inside. At the bottom are two cards. In summary, the complete contents are as follows:
- 1 ST2 PRO.
- 3 pairs of ergonomic white silicone ear cushions, sizes SxMxL.
- 1 USB-C to USB-A adapter.
- 1 HIDIZS bag.
- User manual.
- Warranty Card.
- Product Quality Certificate.
It still carries Hidizs' synthetic leather pouch instead of a zippered case, as is already the case with other, even more expensive, models that only include a set of accessories. But the USB Type-C to Type-A converter is appreciated. Good.


Construction and Design
The capsules have a semi-custom shape and are made of resin, except for the outer part and the mouthpieces, which are made of aluminum alloy. The resin is transparent, so you can see the inside, the wires and the driver. The 2-pin, 0.78 mm thick, oval-shaped connection plate is located on the bottom edge. On the edge, in silver ink, you can read “Hidizs Nebula” and the marking indicating the channel. The mouthpieces are metallic, golden and have three diameters: base (6.6 mm), central part (4.8 mm) and crown (6 mm), and an approximate height of 5.5 mm. There is a hole in the center of the inner face.
The DSP cable is constructed with four wires and 260 cores. It is composed of two braided strands with black and purple textile coating. The metal parts are dark gray and made of aluminum alloy (DAC/AMP sleeve, splitter piece, cylindrical microphone container and button). The DAC/AMP case is oval, flat and has windows through which you can see inside the circuitry. The top face reads MQA on the end opposite the USB Type-C connector. On this side there are several LEDs inside that allow to generate various colors. On the opposite side you can see the ES9281AC PRO chip. Resin has also been used for the transparent parts of this connector. The cable has over-ear guides thanks to a transparent semi-rigid sheath. The connector sleeve is made of slightly angled transparent plastic. The letters indicating the channel are embossed and almost imperceptible. The cable has a branded Velcro strap.
The design of the capsules is quite conventional, with a transparent resin, and the difference is in the external aluminum alloy plate on which the brand and its logo are displayed. On the other hand, I like that the cable has a textile covering that gives it a little more resistance, comfort and softness. The metal parts enhance the look of the DAC/AMP cable, as do the transparent windows that allow you to see inside the circuitry. Other details are the colored LEDs, the USB adapter and the cylinder with microphone and button, which make the product an all-in-one device to replace any Bluetooth system. The next step should be a background noise suppression system for the microphone.


Adjustment and Ergonomics
The most significant thing about the capsules is their low weight of only 7 grams. The semi-custom shape makes for a great fit, but the slightly thicker mouthpieces and the angle to the ear canal can make it difficult to choose the right tips. I have tried my large foam-filled tips with no problems. However, I have found that the sound profile calls for tips with a wider channel to gain clarity and lighten the bass. For this I have used ultra large blue silicone tips, with low profile and large inner core. A good seal is achieved, although the isolation level is not so high. The set is very comfortable, but with these silicone tips the fit can be a bit more critical, as small variations in position can alter the bass response. It is not the fault of the model, but it is true that with my big tips filled with homemade foam, I get a very high bass boost that alters the natural response of the set in an undesirable way. I have looked for alternatives like the Tangzu Tang Sancai Narrow Bore or the black Penon Liqueur Silicone Eartips, but the ones that have worked best for me are these, much cheaper (blue color) and all in extra large size.
https://es.aliexpress.com/item/1005004615505310.html


Sound
Profile
The Hidizs ST2 Pro are a cable-integrated DAC/AMP assembly plus IEMS with a classic V-profile. According to the website, their profile is aligned with the H-2019 target audience. In my opinion, the ST2 Pro's enhance more mid bass and less sub bass. It is also more noticeable in V, with a more sunken midrange and a somewhat steeper rise towards the treble. Then there is a slight area of control in the first treble and an extension that pales in the air area.
Overall, the set is somewhat more emphasized in the bass, with that wide curve in the low area. That's why I've looked for some tips to lower the lower zone and favor the clarity of the whole.

Bass
Bass presence can be noticeable with some tips, but it is an easily correctable problem. I have used low-profile, wide-channel tips to promote separation, clarity and transparency. In this way, the bass does not appear saturated or overly boomy. They offer a clear sense of texture and low-medium speed. They have a moderately compact punch with good retrieval. The bass is rounded, with a sub-bass that is neither too pronounced nor too deep. The low-mid bass is the protagonist, feeling powerful and wide. It has plenty of volume and occupies considerable space, almost with a tendency to overpower.
In the very low frequency pure tone test, the limited emphasis on the sub-bass is noticeable. The audible lower note is barely perceptible, both aurally and sensorially. This detracts from its depth and accentuates its more physical character, centered at 60 Hz. As frequencies rise, the bass becomes more powerful, with a subtle color and wave-like appearance. In reality, this translates into a bass with a rough surface, expansive, powerful and extended, more noticeable than dark and physically powerful, with an obvious and forceful punch.
In the dirty, unfiltered bass test, it is noticeable that the lightness of the sub-bass brings a bit more color than sensory physicality to the sound. In any case, control is better than expected despite the somewhat more conventional sonority of its V-profile. The level of resolution is somewhat limited, although it does its job well in following the bass lines. Its sound is rounder and less defined, which gives a feeling of powerful bass, although relatively simple and not too tight.


Mids
The midrange starts warm and with some strength marked by the extension of the bass. This gives it some physicality in the lower mids and a more powerful base. The rapid descent into V makes the male voices thinner. The sharper they are, the more remote they feel. There is that sense of central hollowness that characterizes this profile. However, the instruments are well represented and are perceived whole and full.
The level of resolution is still on the soft side, appearing more rounded, with a blunt profile, bringing a rather relaxed sense of musicality and with a visible level of macro detail. The central micro detail is perceived as compacted, very attached to the surface, implying a medium level of layering and not too much depth. This micro detail is intuited, but it is not defined in a particular way, but is part of a somewhat thicker and more cohesive line.
The female voices are closer, although their base is not as marked; it is somewhat the reverse of the male voices. However, they are also perceived as warm and round, without too many nuances and with a soft aspect that limits sibilance.
In summary, the mids are musically pleasing, somewhat depressed in their center, cohesive, without too much depth, but remarkably resolved at the macro level.


Treble
The treble begins with a high point, after a slight zone of control, and a second sparkle appears that brings vivacity and a somewhat sharp extension. The level of refinement is medium, relatively pleasant, not too marked, but with a more incisive edge at times. There is a great deal of energy, though it feels somewhat limited in the air zone, already showing drier and more compact. But, although that energy is not predominant in the mix, it is so that the whole does not appear dull, dark or dull. The upper zone has its own entity and shows that it exists on its own and not as a mere accompaniment to the whole. In this way, both the high notes themselves and their harmonic contribution benefit the ensemble.


Soundstage, Separation
What strikes me most about the sound of the ST2 Pro is the volume of the bass. This feature enhances the sense of spaciousness and extension of the soundstage. On the other hand, the layering is simply good, with somewhat cohesive and compact mids. Details are perceived on the surface, while smaller details in the background come closer to it and connect, losing some ability to describe themselves with more rigor and definition.
The scene has good laterality, a level of closeness of the volume more noticeable than the depth itself, and an adequate height. The image is eminently frontal, connected, harmonious and conjunctive, without too much sensation of individuality. In this way, a warm, musical, melodious and soft sensation prevails, which moves away from any forced over-definition. The result is a fairly natural level of separation, with a sense of luminosity, transparency and clarity sufficient to prevent the whole from becoming thick, dark or overly nuanced. I don't miss light, brightness or more transparency. It does lack a little more layering, layer generation and a more evident background.


Comparisons
KBEAR Robin
I like to compare IEMS with similar profiles. Although, in this case, it would have been more appropriate to make a comparison with the INTUAURA Reference 2019, the other IEMS that have a cable with a DAC/AMP. In fact, the Reference 2019 have a DSP that alters the original sound of the IEMS and fixes it to the Reference H2019. For their part, the ST2 Pro have a DSP DAC/AMP cable. The first difference is that both claim to be based on the H2019 curve. Who is closer to the H2019 curve? Judge for yourselves.

My real comparison will be against the KBEAR Robin, an IEMS that are somewhat cheaper than the final price of the Hidizs ST2 Pro set (estimated at $89). Both have a similar capsule, more classic and semi-custom in the Robin. As usual, KBEAR includes a zippered case and two sets of earplugs, though the cable is pretty basic. The Hidizs cable, excluding the DAC/AMP, has a better finish. However, Hidizs only includes a set of tips and a faux-leather pouch.
From an ergonomic standpoint, there should be many similarities, but I find the Robin's fit better and tighter.
As a dongle to play the KBEAR Robin I used the Hidizs SD2.
The Robins have a V profile with a W tendency. They have more sub-bass enhancement and a double peak in the upper mids and first treble.
The similarity in bass is high, as can be seen in the frequency response of both IEMS. The difference lies in the greater presence of sub-bass in the Robins. The bass is large and voluminous in both models. They both have that slightly slower bass style with a longer recovery. It seems darker in the Hidizs, but has more impact and punch in the Robins.
The midrange is also very similar, with a similar transition from bass to midrange, as well as the same valley. Although the Hidizs are a bit darker, I find the male vocals crisper and better defined on the ST2 Pros. The upper mids have more overall energy in the Hidizs, despite that 2 kHz peak in the Robins. This is noticeable in that the ST2 Pro model is subtly more sibilant. However, female vocals seem to have a bit more prominence in the Robins, while there is a sense of overall darkness in the Hidizs, although you could also call it softness.
In the upper range, the highs of the Robins are somewhat softer and less bright. In contrast, I find the treble of the Hidizs to be more natural, distinct, bright, crisp, and realistic. They also have better extension, air and sparkle.
The Robins have a bit more definition, especially in the midrange, with a bit more clarity. The Hidizs are smoother, warmer and more mellow. The greater sense of depth and closer mids make the Robin's soundstage seem a bit larger.

Conclusion
I think Hidizs has joined the new trend of USB DSP cables with integrated DAC/AMP. As smartphones move away from supplying 3.5mm audio output, this new set will become more relevant, especially if the integrated DAC/AMP is as adequate as the ES9281AC PRO. The cable includes microphone and a control button, so it is all-in-one and can be used with any mobile device. The cable can be purchased individually with 2-pin 0.78mm or MMCX interface and is compatible with any IEM on the market that incorporates these connection interfaces.
In this review, the cable is accompanied by IEMS with a V-profile. These are very lightweight capsules, with a dual dynamic driver with a 10mm PU+PEEK composite diaphragm. Their sound is characterized by punchy bass, warm and smooth mids, and bright and energetic highs. The starting price has been set at $39, and on the second pass it will be $49. For that price, the set is excellent.


Sources Used During the Analysis
- PC Windows 10.
- Hidizs AP80 PRO-X Red Copper LE


Hidizs offered me this model, in exchange for writing an honest review. I want to make it clear that all my opinions written in this review have not been conditioned by this fact, nor will I ever write anything that I do not really think or feel here. I will only write about my personal opinion in relation to the revised product.

Purchase Link

You can read the full review in Spanish here

suicideup
New Head-Fier
Pros: An all-rounder, modern everyday carry IEM!
Versatile, v-shaped sound signature!
Firm, punchy bassy response!
Slightly thick mids!
Sparkly, well-extended upper frequencies!
Above-average technical performance for its price!
Excellent fit, comfort, and isolation!
Built-in DAC while having the ability to replace cables makes things easier and practical!
Worry-free drivability!
Versatile, v-shaped sound signature!
Firm, punchy bassy response!
Slightly thick mids!
Sparkly, well-extended upper frequencies!
Above-average technical performance for its price!
Excellent fit, comfort, and isolation!
Built-in DAC while having the ability to replace cables makes things easier and practical!
Worry-free drivability!
Cons: Mild sibilance is present on certain sibilant prone tracks.
IEM build quality is on the “cheaper” side, price-wise.
Barebone accessories.
IEM build quality is on the “cheaper” side, price-wise.
Barebone accessories.

Hidizs ST2 Pro Nebula Review!
Video review here
Good day! After 5 days of casual and critical listening, here’s my written review for the Hidizs ST2 Pro Nebula. Carry the nebula with you!
Disclaimer:
- I don’t read FR graphs. I only use my ears, as earphones should be used.
- Hidizs sent this unit to me in an exchange for an honest, independent review. Rest assured that this review will do its best to devoid from any bias/es as much as possible.
- The following remarks and observations shall be made and owned only by me.
- No monetary compensation is/was involved before, during, and after the period of creation of this review.
- Your mileage may (and always, will) vary.
Burn-in time: 4-8 hours per day, 5 days.
Source/s used:
- - Non-HiFi smartphone (Infinix Note 12 G96), PC.
- - Tanchjim Space DAC
- - Fosi Audio SK02 USB DAC
- - Kiwi Ears Allegro Mini DAC
- - Aiwa XP-V710C CD Player (12 sec. EASS)
- - Sony Xperia X Compact
- - Local Files via Foobar, YouTube Music, Deezer, and Qobuz with UAPP.
========================================================================
Sound signature:
- The Hidisz ST2 Pro Nebula follows the Hidizs house sound wherein it presents itself in a fun, v-shaped sound signature.
- For an EDC setup, I can comfortably say that the bass of the ST2 Pro Nebula will entice, and probably will be enjoyable for bassheads. The bass is elevated, slightly subbass dominant, but does not leave the midbass lacking. Attack and decay leans slightly to the faster side of the spectrum, creating a “clean” yet bassy impression.
- As for the mids, it is a bit recessed to my liking, but it is expected since this is a v-shaped sounding set. Despite this recession, I never found the mids to be too drowning or muffled in any of my test tracks and setups. Lower mids exhibit a bit of warmth, making the lower mids a bit thicker than usual. Upper mids are elevated, bright, clear, and exhibits a good amount of air, but not as bright when compared to its treble. Mild peaks and sibilance are also present in this set on certain sibilant prone tracks, such as Adele’s “Chasing Pavements” and Travis Scott’s “Sicko Mode” as some of the examples. Don’t get me wrong, this won’t be an issue or a concern for most people, but definitely something to take note and be wary of if your ears are extra sensitive to brighter upper frequencies.
- As for the treble, it is slightly bright, well-extended, and has a bit of mild sibilance as well, just like its upper mids. Detail retrieval is slightly above average, and can render microdetails fairly easily.
- When it comes to the technical performance, there is nothing to write home about for this IEM, but that doesn’t mean that it is bad or underwhelming, it’s just that for its asking price, it isn’t uncommon. The soundstage is your usual wider than deep, with a good amount of height. Separation and layering is average at best, with mild hiccups on heavy passages. Imaging is accurate enough and does not have any problems with any of the games and podcasts I have tested this with.
========================================================================
Other IEM Comparisons!
Celest IgniteX Beast
- When compared, the Celest IgniteX Beast is a more balanced, slightly warmer set. Upper frequencies on the Celest IgniteX Beast are also less bright and more safer when compared to the ST2 Nebula. The bass on the IgniteX Beast are also “softer” in character and slightly lacks detail when compared to the ST2 Pro Nebula. The rest are more or less the same.
- The Kefine Klean is a leans to a more mature, balanced, slight warm-v sound signature when compared to the ST2 Pro Nebula. It is noticeably thicker as well. Bass is also firmer and a bit more punchy. Mids is a bit more open on the Kefine Klean when compared, but is also thicker when compared to the ST2 Pro Nebula. Treble is a bit more extended on the Nebula, but both sets have nearly the same detail retrieval. Both sets on technical performance are also nearly the same in quality when it comes to the technical department, as the Klean slightly has “cleaner” separation and layering.
- The Simgot EW200 when compared to the ST2 Pro Nebula is brighter, wider, and lesser in bass IEM. Its technicalities are also better when compared to the ST2 Pro Nebula.
- The Rose Technics Star City 5 Pro is a balanced, well-controlled, safer in treble, and thicker in sound, when compared to the Hidizs ST2 Pro Nebula. Technicalities, particularly on the separation and layering, are better on the Star City 5 Pro.
========================================================================
Pros:
- An all-rounder, modern everyday carry IEM!
- Versatile, v-shaped sound signature!
- Firm, punchy bassy response!
- Slightly thick mids!
- Sparkly, well-extended upper frequencies!
- Above-average technical performance for its price!
- Excellent fit, comfort, and isolation!
- Built-in DAC while having the ability to replace cables makes things easier and practical!
- Worry-free drivability!
- Mild sibilance is present on certain sibilant prone tracks.
- IEM build quality is on the “cheaper” side, price-wise.
- Barebone accessories.
Verdict
- The Hidizs ST2 Pro Nebula offers convenience and practicality in today’s world of nearly zero phones with 3.5mm port. I personally enjoyed this setup with my phone during commutes and running down my errands because I did not have to bring my dongle with me, keeping my everyday carry as simple as it can be. Not to mention that this also exhibits a very versatile sound character that will suit most genres and instances. Very practical indeed, Hidizs!
Pairing recommendations:
- Source: The Hidizs ST2 Pro Nebula has its own USB DAC built in, so you shouldn’t worry about this.
- Eartips: The eartips included pairs well with this IEM, but you may still use your preferred eartips.
- Cable: The cable is sleeved, which I am personally not a fan of, but it is well-made for its price. You may still use your preferred cable since it is detachable, but you may also lose the DSP feature that the stock cable has.
Non-affiliated link here: https://www.hidizs.net/products/hid...mance-dac-usb-c-hifi-digital-in-ear-earphones
Additional Photos Here:









iwatobi
Head-Fier
Pros: • Full-Bodied & Hard-Hitting Mid-Bass
• Native DSD Playback upto 128 & MQA Decoding
• Next Generation DSP Includes a Good DAC-Chip
• Exquisite Imaging
• Impressive Treble
• Clean & Textured Sub-Bass
• Native DSD Playback upto 128 & MQA Decoding
• Next Generation DSP Includes a Good DAC-Chip
• Exquisite Imaging
• Impressive Treble
• Clean & Textured Sub-Bass
Cons: • Bad Stock Ear Tips (Aftermarket Tips Recommended)
• Mids are recessed
• Average Soundstage
• Mids are recessed
• Average Soundstage
Introduction
HIDIZS ST2 Nebula is the latest addition to the HIDIZS line-up that comes with a DSP, which they are calling “The Next Generation DSP”. The DSP cable features a proper and good DAC Chip that is a much-welcomed addition in the market. Moreover, it features a curve that is closer to the 2019 Harman Curve with a slight boost to the mid-bass and is a bit airier, which gives the listener a much more engaged listening experience.
Disclaimer
HIDIZS sent over the ST2 Nebula to our friends at Sonic Mantra for it to be reviewed. Thank you, Sonic Mantra and Hidizs for granting me an opportunity to try out the ST2 Nebula. However, my review is based on what I felt while using the ST2 & was in no way influenced by the team nor Hidizs.The ST2 Nebula can be directly purchased from the Hidizs website, or you can pre-order from Geek Mart if you are from Bangladesh.
Also, do check out their Kickstarter page as well!
Testing Gear
• NiceHCK TC3• JM45
• Next Gen DSP
Specifications
• Customized 10 mm Dual Magnetic Circuit Dynamic Driver• Frequency response: 20Hz-40kHz
• Pin type: 0.78 2pin/MMCX
• Sensitivity: 108dB
• Impedance: 32 Ω
Inside The Package
• The Drivers• DSP Cable
• Three Pairs of ear tips
• USB A to Type C Adapter
• Carrying Pouch
• Paperworks
Build & Design
The body of ST2 is built relatively good and feels durable. It is made from resin, making it a lightweight IEM. The faceplate has a metal-plating that has the Hidizs logo and name engraved. Nonetheless, it feels great to the touch.Fit & Comfort
The ST2 snuggles right in your ears without any hiccups. It is comfortable and lightweight to use. However, tip rolling is recommended. I used two ear tips while testing it. First is Dunu Candy and second is ePro Propeller 01. I will share what I felt after using both ear tips in my review.
Next Generation DSP
The Next Generation DSP is an awesome DSP cable that features a proper DAC chip. I have tested various other IEMs with DSP cables, but this one is special. HIDIZS Next Gen DSP cable can be used on any IEM, and it will without fail drive them properly. I believe there is no other DSP cable in the market that can properly drive other IEMs except for its own stock drivers. The Next Gen DSP cable truly lives up to its name and is in another league compared to any other DSP IEMs in the market.Hidizs Next Generation DSP cable has an ES9281AC PRO chip, which is capable of native DSD playback from DSD64 to DSD128, alongside 8x MQA Decoding and can play PCM up to 32bit/384kHz. Moreover, this cable delivers up to 70mW of power and has a tuning close to the 2019 Harman Curve.

Sound
Before heading into the specifics, let me add a few things here. As stated previously, the tuning is based on a curve that is closer to the 2019 Harman Curve. From the frequency chart, we can notice a slight boost on the mid-bass section and is airier, while leaning towards a V-shape sound signature. The Sound testing was done with and without the DSP cable, with portable DACs. Below are the testing results while using the DSP Cable.Sub-Bass
The sub-bass of the ST2 with ePro Propeller 01(PR01) tips leaves much to be desired. Even though there is an emphasis on the sub-bass, it does not match up to the expectations. There is adequate rumble, presence and depth, but the sub-bass is clean and textured.The sub-bass of the ST2 with Dunu Candy tips has minimal presence than with the ePro PR01. But the depth is enhanced, and it remains clean & textured.
Mid-Bass
The mid-bass of ST2 with ePro PR01 tips are hard-hitting and clean. The performance of the mid-bass will attract the mid-bass lovers and general listeners. Fortunately, the mids-bass does not bleed into the lower Mids.The mid-bass of Candy tips are not as hard-hitting as the PR01 but is clean, thick, and energetic. Nonetheless, it is still enjoyable and a bit more engaging than the ePro Propeller 01 tips for me. In some songs, the mid-bass bleeds into the midrange ever so slightly.
Mid-Range
There isn’t anything noteworthy, apart from the fact that the mids are not overshadowed by the lows and highs. Moreover, the vocals are recessed due to the mild V-shaped curve; with the ePro PR01 tips.The mid-range completely changes with the Candy tips! It became affluent and a bit rich, and still it was not overshadowed by the lows and highs.
Male Vocals
Male vocals on the ST2 Nebula are quite laid-back, but are smooth and textured. It does not have any harshness but sometimes makes my listening experience dull at times as it is more laid-back than I prefer; with the ePro PR01 tips. Also, it had better separationOn the other hand, the vocals took a huge turn with the Candy tips! It became less laid-back, more textured, smoother and focused. However, it was a bit recessed and had lesser separation. Nonetheless, I enjoyed it even more than I did with the ePro PR01.
Female Vocals
Female vocal lacks clarity, lacks liveliness, is harsh at times, but at least it is smooth with the ePro PR01.Again, the vocals gained clarity and is livelier on the Candy tips. Moreover, it lowers the harshness than with the PR01 tips. It does make the female artists tracks even more engaging and forward. Regardless, the Candy tips made a huge change to the vocals than the ePro PR01 tips.
Instruments
The instruments are fortunately forward and lively enough. However, many listeners might not enjoy it as it is not forward, or lively as other listeners might want it to be. Another thing, the instruments are not harsh; with the ePro PR01 tips.The instruments were a tad bit livelier with the Candy tips; the rest was the same. I enjoyed it.
Treble
The treble with the ePro PR01 is bright, airy, energetic and incredible extension, which is engaging for the listeners. Moreover, the cymbals and hi-hats are crisp, while still not being sibilant or harsh, which is a plus point for treble-sensitive listeners.With the Dunu Candy tips, the treble remains similar, but it loses a bit of crispiness on the cymbals and hi-hats.
Soundstage & Imaging
The soundstage on ST2 Nebula with the ePro tips is nothing extraordinary. The soundstage adds a tad bit of sense of space. It mostly lacks the width and vividness of spaciousness. However, the imaging is precise, which makes it easy to appropriately know the instruments or vocals placement.The soundstage does not increase, nor attain, any enhancement with the Dunu Candy tips.
Non-DSP Cable Sound
To me, the ST2 Nebula did not sound as fun as it did with the DSP cable. Apart from the sparkly and bright sound, alongside the newly introduced sibilance which was prominent in every song. I believe ST2 Nebula performs the best with the DSP cable and I will recommend the listeners to use the DSP cable with it.
Conclusion
The HIDIZS ST2 Pro is an incredible IEM with insane value. It is a very convenient IEM that is just plug and play. You do not need to carry an additional portable DAC with a good chip that can provide you native DSD playback, MQA 8x decoding and PCM up to 32bit/384kHz. Their Next Generation DSP cable provides them all in a form that is already present in the market. I have yet to see a DSP cable that can outperform this DSP cable in such a way. Moreover, you can fine tune this however you want to use EQ as it is a DSP cable. Additionally, the cable is cross-compatible with every device that has a type C port; an adapter can be used as well if you lack a type C part on your device.Finally, the ST2 IEM is a must-have for a listener who loves a clean and hard-hitting mid-bass, laid-back vocals and a crispy but smooth treble. It also is not sibilant or harsh in any point. And the microphone that the DSP cable comes with is incredibly good. It is able to cut down on the background noise and only capture the speaker's voice extremely precisely and clearly.
If you purchase the ST2 Nebula IEM, you will get the Next Generation DSP cable which is universal and works with any IEM; you are also getting the IEMs itself, which is a great choice if you want incredible mid-bass and an extravagant treble that is bright, but not sibilant. Moreover, the vocals are good, even though it is a bit recessed.
Tip Rolling
Tip rolling is essential for every IEM, especially this. The stock tips do not do the IEM justice. The ePro Propeller 01 makes the sound a bit analytical, while the DUNU Candy makes the sound fun and engaging.
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Mataudiophiles
New Head-Fier
Pros: Cable with DAC, entertaining sound, quality of workmanship, comfort.
Cons: stock nail tips
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MatAudiophiles
When music flows in your veins, choose a good guide!
INSTAGRAM: LINK
YouTube: LINK
HIDIZS ST2 PRO Nebula
Prelude:
Manufacturers of audio equipment do not have an easy life, the competition is extremely strong, and the number of fascinating products is constantly growing. For this reason, it is increasingly difficult to surprise a potential recipient with something and find a niche in which there is room to maneuver. An interesting alternative are headphones with a USB C cable. Most often, these are ordinary basic systems, but not this time. An interesting fact is that the HIDIZS ST2 PRO Nebula uses a full-fledged digital-to-analog converter ES9281AC PRO as a DAC and provides an astonishing 70mW of power per channel. Additionally, we have full MQA support (Yes, I know that this format is currently dead, but it is worth mentioning that such an option exists.). Additionally, we have DSD support in the DSD64 and 128 standards and full PCM support 384kHz/32Bit. Objectively speaking, these are really impressive values even for a cable with a DAC alone, and after all, we also have headphones in the set. It is worth noting that at the moment the price of HIDIZS ST2 PRO Nebula has not been given yet, but knowing the pricing policy HIDZIS will not price this product too high.
Unboxing:
First of all, I would like to invite you to my YouTube channel where you can watch my video with the unboxing of HIDIZS ST2 PRO Nebula, and here is the appropriate link. If you do not want to break away from reading, I invite you to continue reading. Classically, HIDIZS ST2 PRO Nebula comes to us in a nice small box. Inside we will find the headphones themselves, they are made of plastic with very good properties and a semi-transparent housing. Thanks to this, we can admire the interior of our headphones and enjoy great comfort of wearing them. On the front we will find a gold front panel panel with the manufacturer’s logo. It is worth emphasizing here that the headphones in this case are an independent part and have detachable 0.78 mm sockets. Another important element of the set are the tips, which are, however, the weakest element of the set itself and a black soft case made of ecological leather. Time for the promised star of this giveaway, the DAC cable itself. In the case of the HIDIZS ST2 PRO Nebula, we get a solid braided cable made in coaxial technology. It has braided fibers in a braid and is completely independent of the headphones. The end of the cable is terminated with a USB C plug with a transparent housing, through which we can admire the DAC itself. They also thought about a small signal diode. This is a pretty solid set and I didn’t miss much in it, apart from a hard case.
Sound:
In terms of test materials, I used Tidal and popular playlists.
Low tones:
As befits tuning on the Harman set, we have a pulsating, airy bass. Our music is presented on the set of a light U, which means that the bass notes are raised, and the whole thing is very musical. Regardless of the song chosen, the entertaining and pleasant character of the low tones will accompany us. Fortunately, the low tones are not overly exposed. I would describe them as musical and saturated. It is worth emphasizing that the low tones in the HIDIZS ST2 PRO Nebula are engaging and although there is more midbass than subbass impact, the whole is definitely saturated with low tones and does not give the impression of being too contoured or reference.
Midtones:
The vocals are slightly recessed, thanks to which the sound stage is larger and more exposed. It is worth noting that despite such a procedure, the whole does not sound excessively recessed or unattractive. Fortunately, the HIDIZS ST2 PRO Nebula are headphones that offer a sufficiently good vocal presentation. It is also worth emphasizing that when it comes to the amount of information and details offered by the HIDIZS ST2 PRO Nebula, it is really quite large. The sound remains detailed, and the planes are perfectly outlined, each instrument or detail is in the right place and allows us to enjoy our favorite music without worries.
High tones:
Although the HIDIZS ST2 PRO Nebula is a set offering tuning on the U plane, the high tones are nevertheless properly tamed. Of course, the higher registers are raised above the vocal line, but the overall presentation of the highs is very comfortable and provides an excellent listening experience. This is important because the HIDIZS ST2 PRO Nebula are a set focused on entertainment, but at the same time they offer versatile and detailed tuning. However, if you expect brilliance and resolution, then you need to remember that the higher frequencies in the HIDIZS ST2 PRO Nebula are not overly boosted to the limits of their capabilities. These are still dynamic headphones and this should not be forgotten.
HIDIZS ST2 PRO Nebula- DAC Cable itself
It is worth emphasizing here that a huge advantage of the HIDIZS ST2 PRO Nebula is the independent cable with DAC/AMP, it is of very high quality for this type of cables and offers very good tuning. The cable itself provides a lot of power and is enough for most headphones. Now, in the era of moving away from the jack socket, this is a big advantage. When it comes to the sound of the HIDIZS ST2 PRO Nebula cable itself, you can definitely hear that it is based on the DAC system from Sabre. Here we have detailed tuning with a stronger accent on the bass and crystal clear treble. All in all, this is a very good DAC/AMP in a headphone cable, I would venture to say that one of the best.
Comparisons:
HIDIZS ST2 PRO Nebula VS ddHIFI M130B
Here I would like to compare two very good cables with DAC available on the market. Of course, the HIDIZS ST2 PRO Nebula also includes headphones, but I would like to focus on the cables themselves. So yes, the sound of the HIDIZS ST2 PRO Nebula is darker and offers more fun in tuning, more bass, and the cable itself is thinner and lighter. However, the USB C end itself is relatively large, I know that it is still a small DAC at the end, but the ddHIFI M130B shows that it can be miniaturized even more. The sound of the ddHIFI M130B is brighter, a bit less musical, and more reference, compared to the HIDIZS ST2 PRO Nebula. Although in general both proposals are really great.
For whom will the HIDIZS ST2 PRO Nebula be a better option:
Here I would like to emphasize that I will include the HIDIZS ST2 PRO as a whole. First of all, we have more air and information, more withdrawn vocals with a smaller sound stage. While the appropriately reinforced MP145 still offer better technical parameters and more balance in sound. However, in terms of comfort, the HIDIZS ST2 PRO still fares better, even despite the uncomfortable tips in the packaging. So if you want a cable with a DAC and headphones, definitely choose the HIDIZS ST2 PRO. However, if you just want good headphones, it’s worth reaching for the MP145 planar headphones.
For whom will the HIDIZS ST2 PRO Nebula be a better proposition:
Summary:
Although I don’t know the price of the HIDIZS ST2 PRO Nebula yet, I already know and I can tell you that this is a really strong proposition. The headphones themselves offer a musical sound on the U plane, but in combination with a dedicated cable with a DAC they show their true potential. The sound offered by the HIDIZS ST2 PRO Nebula is extremely musical and detailed. The amount of information we receive is truly amazing. This is one of the most interesting DAC cables on the market and offers very good tuning. That is why I think that the HIDIZS ST2 PRO Nebula is a very good set for people who are looking for entertaining tuning with a universal and pleasant presentation. A good addition offered by the HIDIZS ST2 PRO Nebula is also a good quality microphone that allows for free communication and conversations without having to reach for the phone. That is why I am personally very impressed with the new project that is the HIDIZS ST2 PRO Nebula and I highly recommend it.
Why choose HIDIZS ST2 PRO Nebula:

MatAudiophiles
When music flows in your veins, choose a good guide!
HIDIZS ST2 PRO Nebula

INSTAGRAM: LINK
YouTube: LINK
HIDIZS ST2 PRO Nebula
Prelude:
Manufacturers of audio equipment do not have an easy life, the competition is extremely strong, and the number of fascinating products is constantly growing. For this reason, it is increasingly difficult to surprise a potential recipient with something and find a niche in which there is room to maneuver. An interesting alternative are headphones with a USB C cable. Most often, these are ordinary basic systems, but not this time. An interesting fact is that the HIDIZS ST2 PRO Nebula uses a full-fledged digital-to-analog converter ES9281AC PRO as a DAC and provides an astonishing 70mW of power per channel. Additionally, we have full MQA support (Yes, I know that this format is currently dead, but it is worth mentioning that such an option exists.). Additionally, we have DSD support in the DSD64 and 128 standards and full PCM support 384kHz/32Bit. Objectively speaking, these are really impressive values even for a cable with a DAC alone, and after all, we also have headphones in the set. It is worth noting that at the moment the price of HIDIZS ST2 PRO Nebula has not been given yet, but knowing the pricing policy HIDZIS will not price this product too high.
Unboxing:
First of all, I would like to invite you to my YouTube channel where you can watch my video with the unboxing of HIDIZS ST2 PRO Nebula, and here is the appropriate link. If you do not want to break away from reading, I invite you to continue reading. Classically, HIDIZS ST2 PRO Nebula comes to us in a nice small box. Inside we will find the headphones themselves, they are made of plastic with very good properties and a semi-transparent housing. Thanks to this, we can admire the interior of our headphones and enjoy great comfort of wearing them. On the front we will find a gold front panel panel with the manufacturer’s logo. It is worth emphasizing here that the headphones in this case are an independent part and have detachable 0.78 mm sockets. Another important element of the set are the tips, which are, however, the weakest element of the set itself and a black soft case made of ecological leather. Time for the promised star of this giveaway, the DAC cable itself. In the case of the HIDIZS ST2 PRO Nebula, we get a solid braided cable made in coaxial technology. It has braided fibers in a braid and is completely independent of the headphones. The end of the cable is terminated with a USB C plug with a transparent housing, through which we can admire the DAC itself. They also thought about a small signal diode. This is a pretty solid set and I didn’t miss much in it, apart from a hard case.

Sound:
In terms of test materials, I used Tidal and popular playlists.
Low tones:
As befits tuning on the Harman set, we have a pulsating, airy bass. Our music is presented on the set of a light U, which means that the bass notes are raised, and the whole thing is very musical. Regardless of the song chosen, the entertaining and pleasant character of the low tones will accompany us. Fortunately, the low tones are not overly exposed. I would describe them as musical and saturated. It is worth emphasizing that the low tones in the HIDIZS ST2 PRO Nebula are engaging and although there is more midbass than subbass impact, the whole is definitely saturated with low tones and does not give the impression of being too contoured or reference.
Midtones:
The vocals are slightly recessed, thanks to which the sound stage is larger and more exposed. It is worth noting that despite such a procedure, the whole does not sound excessively recessed or unattractive. Fortunately, the HIDIZS ST2 PRO Nebula are headphones that offer a sufficiently good vocal presentation. It is also worth emphasizing that when it comes to the amount of information and details offered by the HIDIZS ST2 PRO Nebula, it is really quite large. The sound remains detailed, and the planes are perfectly outlined, each instrument or detail is in the right place and allows us to enjoy our favorite music without worries.
High tones:
Although the HIDIZS ST2 PRO Nebula is a set offering tuning on the U plane, the high tones are nevertheless properly tamed. Of course, the higher registers are raised above the vocal line, but the overall presentation of the highs is very comfortable and provides an excellent listening experience. This is important because the HIDIZS ST2 PRO Nebula are a set focused on entertainment, but at the same time they offer versatile and detailed tuning. However, if you expect brilliance and resolution, then you need to remember that the higher frequencies in the HIDIZS ST2 PRO Nebula are not overly boosted to the limits of their capabilities. These are still dynamic headphones and this should not be forgotten.
HIDIZS ST2 PRO Nebula- DAC Cable itself
It is worth emphasizing here that a huge advantage of the HIDIZS ST2 PRO Nebula is the independent cable with DAC/AMP, it is of very high quality for this type of cables and offers very good tuning. The cable itself provides a lot of power and is enough for most headphones. Now, in the era of moving away from the jack socket, this is a big advantage. When it comes to the sound of the HIDIZS ST2 PRO Nebula cable itself, you can definitely hear that it is based on the DAC system from Sabre. Here we have detailed tuning with a stronger accent on the bass and crystal clear treble. All in all, this is a very good DAC/AMP in a headphone cable, I would venture to say that one of the best.

Comparisons:
HIDIZS ST2 PRO Nebula VS ddHIFI M130B
Here I would like to compare two very good cables with DAC available on the market. Of course, the HIDIZS ST2 PRO Nebula also includes headphones, but I would like to focus on the cables themselves. So yes, the sound of the HIDIZS ST2 PRO Nebula is darker and offers more fun in tuning, more bass, and the cable itself is thinner and lighter. However, the USB C end itself is relatively large, I know that it is still a small DAC at the end, but the ddHIFI M130B shows that it can be miniaturized even more. The sound of the ddHIFI M130B is brighter, a bit less musical, and more reference, compared to the HIDIZS ST2 PRO Nebula. Although in general both proposals are really great.
For whom will the HIDIZS ST2 PRO Nebula be a better option:
- For people looking for more entertainment in sound
- For people looking for a more mobile cable
- for people who like stronger bass exposure
- For people looking for brighter tuning
- For people looking for more high tones
- For people looking for a smaller USB C DAC.
Here I would like to emphasize that I will include the HIDIZS ST2 PRO as a whole. First of all, we have more air and information, more withdrawn vocals with a smaller sound stage. While the appropriately reinforced MP145 still offer better technical parameters and more balance in sound. However, in terms of comfort, the HIDIZS ST2 PRO still fares better, even despite the uncomfortable tips in the packaging. So if you want a cable with a DAC and headphones, definitely choose the HIDIZS ST2 PRO. However, if you just want good headphones, it’s worth reaching for the MP145 planar headphones.
For whom will the HIDIZS ST2 PRO Nebula be a better proposition:
- For lovers of sound on the U plan
- For lovers of cables with DAC
- For people with smaller ears
- For people looking only for headphones
- For lovers of planar sound
- For people who like to change the sound using filters or another DAC/AMP

Summary:
Although I don’t know the price of the HIDIZS ST2 PRO Nebula yet, I already know and I can tell you that this is a really strong proposition. The headphones themselves offer a musical sound on the U plane, but in combination with a dedicated cable with a DAC they show their true potential. The sound offered by the HIDIZS ST2 PRO Nebula is extremely musical and detailed. The amount of information we receive is truly amazing. This is one of the most interesting DAC cables on the market and offers very good tuning. That is why I think that the HIDIZS ST2 PRO Nebula is a very good set for people who are looking for entertaining tuning with a universal and pleasant presentation. A good addition offered by the HIDIZS ST2 PRO Nebula is also a good quality microphone that allows for free communication and conversations without having to reach for the phone. That is why I am personally very impressed with the new project that is the HIDIZS ST2 PRO Nebula and I highly recommend it.
Why choose HIDIZS ST2 PRO Nebula:
- Excellent cable with DAC
- Great build quality
- Good entertaining tuning
- What would I change in HIDIZS ST2 PRO Nebula:
- I would like nozzles to adjust the sound
- Stock tips are of poor quality.
I am personally glad that there are projects like HIDIZS ST2 PRO Nebula, because they allow you to enjoy pure pleasure from music. At the same time, they are extremely universal, who knows, maybe in the next edition we will see Bluetooth modules!
Sifxt
500+ Head-Fier
Pros: Harman tune with tweaks
Clean and thumpy mid-bass
Next Gen DSP includes a proper DAC chip
MQA & Native DSD support
Imaging is quite good
Clean and thumpy mid-bass
Next Gen DSP includes a proper DAC chip
MQA & Native DSD support
Imaging is quite good
Cons: Mids are too recessed
Ear tips aren't great
Some female artist sound harsh
Ear tips aren't great
Some female artist sound harsh
Hidizs ST2 PRO: "THE NEXT GEN DSP!"
The Hidizs ST2 Pro Nebula is a new iem from Hidizs coming with the next generation DSP as Hidizs says and it features a near 2019 Harman curve sound signature with a slight touch of Hidizs magic. It has a slight mid-bass boost and a bit more air making it a lot more fun and engaging to listen to.
NOTE
Hidizs sent this to my friends at Sonicmantra.org for review purposes. Huge thanks to Hidizs and the Sonic Mantra team. However, these are my honest opinions; I am not being paid or influenced in any way to say anything good or bad.
If you want to purchase this product you can order from Hidizs themselves or if you are from Bangladesh you can pre-order them from Geek Mart.
Check out their Kickstarter page as well!
TESTING GEAR'S
• Cayin RU7
• ddHiFi TC44Pro E2
• Onix Alpha XI1
• Fiio Btr7
SPECIFICATION'S
• Customized 10mm Dual Magnetic Circuit Dynamic Driver
• Frequency response: 20Hz-40kHz
• Pin type: 0.78 2pin/MMCX
• Sensitivity: 108dB
• Impedance: 32Ohms
WHAT'S IN THE BOX
• Iem itself
• DSP Cable
• 3 Pairs of ear tips
• Usb to Type C adapter
• Carrying pouch
BUILD & DESIGN
The ST2 is built fairly well I'd say, nothing extraordinary. Made up of resin for the most making it very lightweight with a circular metal portion on the faceplate featuring the Hidizs logo and name. Design-wise I'm not a fan of how Hidizs implemented the whole circular portion with the resin body, I'd prefer a whole resin built or a metal build shell but that's just my opinion, many might prefer this over using just either of them.
FIT & COMFORT
Fit on these is good, needs a bit of tip rolling to get the perfect fit, and then you're good to go. Comfort-wise in my testing it took some time to get used to it, initially, it became slightly uncomfortable after a while but later on, it got to the point where I even forgot I was wearing them. I don't think comfort will be an issue for anybody as the shells are quite ergonomic in shape.
NEXT GENERATION DSP
As Hidizs describes this DSP as the “Next Generation DSP”, I don't think they are just messing around with those terms. They mean some serious business, previously I have had the opportunity to try and test out multiple iem featuring a DSP cable but this takes the crown with not only its specification but also its sound. Specification-wise it has an ES9281AC PRO chip and can play up to PCM 32bit/384Khz, MQA 8X unfolding and more importantly it supports native DSD playback up to DSD 128. These are something no DSP cables have ever done before. Also, this delivers up to 70mW of power and these DSPs are the ones giving it that 2019 Harman curve sound signature.
SOUND
As I’ve mentioned previously these are based on the 2019 Harman curve with a slight boost in the mid-bass section and air region, leaning towards a V-shaped sound signature. I've done my testing with the DSP cable and also with other non-DP cables with different portable dac’s. These are my thoughts on how it sounded with the DSP cable:
BASS
Even though more emphasis has been put on the sub-bass section, these don't rumble as much as many would want but it is an overall clean and textured sub-bass. While it might please everybody it surely will with its mid-bass performance as it delivers some deep and hard-hitting mid-bass punch or thump which not is very prominent in the mix but also doesn't bleed on the lower mids.
MIDS
The mids are quite recessed as expected due to its mild V-shaped sound signature, though they don't get overshadowed by the lows or highs. Male vocals sound laid back ,smooth and full-bodied. Female vocals on the other hand lack the liveliness and overall smoothness and some out as harsh (although very rarely). Thankfully instruments sound right, though not as lively or upfront as many might want but not harsh.
TREBLE
Treble section is done in a way that is bright, energetic, has great extension, and a lot of air that gives it that engaging factor or that instant wow factor. More importantly Cymbals, hi-hats sound crisp but never harsh or sibilant making it a great choice for people who are treble-sensitive.
SOUNDSTAGE AND IMAGING
The soundstage on ST2 PRO are nothing extraordinary just average, and gives off a sense of space. It mainly lacks the width and feels a bit intimate that's all. Imaging on the other hand is quite precise making it easy to pinpoint instruments or vocals.
TIP ROLLING
I've tested it with the stock ear tips as well as the after market ones such as the Spin fit W1 , ePro propeller , final e clear etc. I've found that the ePro propeller pairs with it the best , will highly recommend getting this ear tip for this iem.
WITHOUT DSP
The ST2 achieves a proper V-shaped tuning with an aftermarket cable and a separate DAC, in contrast to the tuning produced with the DSP cable. The sound got a real kick in the high-end, making it more exciting to listen to. It's like turning up the volume on the bright, sparkly parts of the music. Unfortunately, this also brought out a prominent sibilance, that can be a little tiresome. While the low-end stayed pretty much the same, the overall sound became definitely more engaging.
CONCLUSION
The HIDIZS ST2 Pro Nebula would be an awesome IEM if you want a hassle free IEM, where you do not have carry a separate DAC dongle nor want to own a basic DSP IEM as they sometimes lack much needed features such as the DSD playback, MQA decoding and a proper DAC chip. The Next Generation DSP offers everything you would need in one small and simple package. Moreover, the IEM offers a clean, thumpy and hard-hitting mid-bass with laid back vocals and a smooth treble, that is bright but not harsh or sibilant in anyway. It also comes with an awesome microphone that has incredible noise-cancellation feature. All of those features in the same form factor as other DSP IEMs readily available in the market.
The Hidizs ST2 Pro Nebula is a new iem from Hidizs coming with the next generation DSP as Hidizs says and it features a near 2019 Harman curve sound signature with a slight touch of Hidizs magic. It has a slight mid-bass boost and a bit more air making it a lot more fun and engaging to listen to.

NOTE
Hidizs sent this to my friends at Sonicmantra.org for review purposes. Huge thanks to Hidizs and the Sonic Mantra team. However, these are my honest opinions; I am not being paid or influenced in any way to say anything good or bad.
If you want to purchase this product you can order from Hidizs themselves or if you are from Bangladesh you can pre-order them from Geek Mart.
Check out their Kickstarter page as well!
TESTING GEAR'S
• Cayin RU7
• ddHiFi TC44Pro E2
• Onix Alpha XI1
• Fiio Btr7
SPECIFICATION'S
• Customized 10mm Dual Magnetic Circuit Dynamic Driver
• Frequency response: 20Hz-40kHz
• Pin type: 0.78 2pin/MMCX
• Sensitivity: 108dB
• Impedance: 32Ohms
WHAT'S IN THE BOX
• Iem itself
• DSP Cable
• 3 Pairs of ear tips
• Usb to Type C adapter
• Carrying pouch
BUILD & DESIGN
The ST2 is built fairly well I'd say, nothing extraordinary. Made up of resin for the most making it very lightweight with a circular metal portion on the faceplate featuring the Hidizs logo and name. Design-wise I'm not a fan of how Hidizs implemented the whole circular portion with the resin body, I'd prefer a whole resin built or a metal build shell but that's just my opinion, many might prefer this over using just either of them.

FIT & COMFORT
Fit on these is good, needs a bit of tip rolling to get the perfect fit, and then you're good to go. Comfort-wise in my testing it took some time to get used to it, initially, it became slightly uncomfortable after a while but later on, it got to the point where I even forgot I was wearing them. I don't think comfort will be an issue for anybody as the shells are quite ergonomic in shape.

NEXT GENERATION DSP
As Hidizs describes this DSP as the “Next Generation DSP”, I don't think they are just messing around with those terms. They mean some serious business, previously I have had the opportunity to try and test out multiple iem featuring a DSP cable but this takes the crown with not only its specification but also its sound. Specification-wise it has an ES9281AC PRO chip and can play up to PCM 32bit/384Khz, MQA 8X unfolding and more importantly it supports native DSD playback up to DSD 128. These are something no DSP cables have ever done before. Also, this delivers up to 70mW of power and these DSPs are the ones giving it that 2019 Harman curve sound signature.


SOUND
As I’ve mentioned previously these are based on the 2019 Harman curve with a slight boost in the mid-bass section and air region, leaning towards a V-shaped sound signature. I've done my testing with the DSP cable and also with other non-DP cables with different portable dac’s. These are my thoughts on how it sounded with the DSP cable:

BASS
Even though more emphasis has been put on the sub-bass section, these don't rumble as much as many would want but it is an overall clean and textured sub-bass. While it might please everybody it surely will with its mid-bass performance as it delivers some deep and hard-hitting mid-bass punch or thump which not is very prominent in the mix but also doesn't bleed on the lower mids.
MIDS
The mids are quite recessed as expected due to its mild V-shaped sound signature, though they don't get overshadowed by the lows or highs. Male vocals sound laid back ,smooth and full-bodied. Female vocals on the other hand lack the liveliness and overall smoothness and some out as harsh (although very rarely). Thankfully instruments sound right, though not as lively or upfront as many might want but not harsh.
TREBLE
Treble section is done in a way that is bright, energetic, has great extension, and a lot of air that gives it that engaging factor or that instant wow factor. More importantly Cymbals, hi-hats sound crisp but never harsh or sibilant making it a great choice for people who are treble-sensitive.

SOUNDSTAGE AND IMAGING
The soundstage on ST2 PRO are nothing extraordinary just average, and gives off a sense of space. It mainly lacks the width and feels a bit intimate that's all. Imaging on the other hand is quite precise making it easy to pinpoint instruments or vocals.
TIP ROLLING
I've tested it with the stock ear tips as well as the after market ones such as the Spin fit W1 , ePro propeller , final e clear etc. I've found that the ePro propeller pairs with it the best , will highly recommend getting this ear tip for this iem.

WITHOUT DSP
The ST2 achieves a proper V-shaped tuning with an aftermarket cable and a separate DAC, in contrast to the tuning produced with the DSP cable. The sound got a real kick in the high-end, making it more exciting to listen to. It's like turning up the volume on the bright, sparkly parts of the music. Unfortunately, this also brought out a prominent sibilance, that can be a little tiresome. While the low-end stayed pretty much the same, the overall sound became definitely more engaging.
CONCLUSION
The HIDIZS ST2 Pro Nebula would be an awesome IEM if you want a hassle free IEM, where you do not have carry a separate DAC dongle nor want to own a basic DSP IEM as they sometimes lack much needed features such as the DSD playback, MQA decoding and a proper DAC chip. The Next Generation DSP offers everything you would need in one small and simple package. Moreover, the IEM offers a clean, thumpy and hard-hitting mid-bass with laid back vocals and a smooth treble, that is bright but not harsh or sibilant in anyway. It also comes with an awesome microphone that has incredible noise-cancellation feature. All of those features in the same form factor as other DSP IEMs readily available in the market.
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IryxBRO
500+ Head-Fier
Pros: universal compatibility, good IEMs, transparent dac
Cons: little bit harsh on treble

Hidizs ST2 Nebula – the new great option for audio fans with a smartphones missing a dedicated analog audio output and for those, who don’t like cumbersome desk setups with the external DAC/AMPs. All-in-one, universal solution that combines everything – high-quality IEMs, type-C DAC/AMP and even HD mic with phone control button. Time to test whether such bundle does the trick of delighting a demanding user, performing good in both – audio and everyday general use.
Being a fan of single dynamic IEMs, I am glad that Hidizs intends this bundle in particular. Not limited to single type of IEMs – you can use any model of your choice with 2pin / MMCX connector to use with this DAC/AMP on a cable – but the supplied IEMs are the most universal in its tuning, shape, performance and price. Single DD, 10mm DMC lightweight diaphragm, large resonance chamber and H-2019 target curve – what can be more convenient for most of the ears? What I mean by that is that Hidizs made a move to present something that can go easy on every person, no matter which smartphone/laptop/pc/tablet and OS he uses, no matter the music genre he or she likes and no matter what size and shape of the ears he/she has. Nebula should fit and satisfy any. Type-C brings the possibility to connect to most of the modern devices, custom shape is the most versatile, H-2019 curve and dynamic diaphragm combination makes music smooth and crosses out high peaks. Plus the ability to use mic and watch videos with zero-latency… It is only left to try out and find whether everything declared goes flawlessly.

Hidizs ST2 Nebula specs:
IEMs:
- 10mm DD, dual magnetic circuit diaphragm
- resin + aluminum alloy etching shells
- freq.range 20Hz-40kHz
- 0,78 2pin/MMCX ports
- inline control + HD mic
- sensitivity 108dB
- impedance 32Ohms
- weight 7g
- ES9281AC PRO
- 32bit/384kHz / Native DSD 64/128
- MQA 8X
- distortion 0,0012%
- snr 118dB
- dynamic range 122dB
- ch.separation 63dB
- output power 70+70mW

Box contents, design and build quality:
Nebula fits to small black box, traditionally with silver shiny names, logos and product pics. Two layers inside, one to secure IEMs in place and additional pouch with handy opening mechanism found underneath. Cable is located inside this pouch. Personally, I don’t like that the pouch has some soft cloth inside as the velcro tape around the cable is quite sticky… Anyway, it does it job of keeping IEMs scratch-free in real life. Additionally, there are couple of small bags with a set of silicone ear tips and USB A -> USB C adapter.
Having such adapter means that Nebula has everything you need to use it with PC/laptops that don’t feature type-C ports.

Always been a fan of transparent materials used in the design of electronic equipment. ST2 features not only transparent IEM shell to see its neat cable management and channels but also the body of DAC/AMP is a combination of aluminum and glass. This opens its internal circuitry for observation and brings the additional feature: LED sample rate indicator. This has been a distinctive feature across all Hidizs products for a long time now. Not saying that it is very informative, but you can easily differentiate SD/HD track sample rate, at least.

IEM shells are available in dark / light options, all equipped with 0,78mm/2pin ports for cable and have long protruding output nozzles, ending up with protective mesh.
As far as I understand, Hidizs would also make ST2 Nebula cable with integrated DAC/AMP available separately, in two versions: 2pin and MMCX types of connectors. This would allow make any IEMs compatible with most of type-C devices.

Cable that came in my bundle is 0,78/2pin type, wrapped in textile yarn, has flexible ear guides, equipped with HD mic and inline remote button and ends with the aluminum DAC/AMP shell. Feels sturdy enough to live long and serve its purpose for many IEMs that I would like to try out in such scenario in the future.
In use:
Couple of words here about ST2 Nebula operation: as already mentioned – it is compatible with any USB type-C equipped device that has the ability to recognize external DAC. Windows, Mac OS based desktops or laptops, perhaps Linux based platforms, Android/iOS tablets and smartphones with OTG support… Hidizs says that only IPhone 15 and later are compatible (I am not Apple fan – only IPhones starting from 15 has type-C????). Even if you don’t have type-C, you can try to use USB A -> type-C adapter or some USB hub. Even Hidizs AP80 player running Linux-based HiBy OS has successfully recognized Nebula as an external DAC.

Since this device is passive (doesn’t have a battery) – it relies on USB power. Not a big deal for any device, except the smallest ones like Hidizs AP80 DAP which recognizes and utilizes USB DAC perfectly but the battery drain goes faster. What I’ve noticed is that Nebula gets quite warm, especially with HD quality tracks. About 42 deg.C after 15-20 minutes of indoor use. SD quality doesn’t have such impact. Anyway, 42C is nothing to worry about. Just having a warm little powerhouse in your pocket. Power consumption is about 50-55mA @ 5V.

Sound quality:
Since IEMs are tuned accordingly to H-2019 curve, they produce smooth sound with no accents or unexpected peaks. This is a slight V-shaped tuning with rich but slightly congested lows, dynamic and tight mid bass, natural and mellow mids and balanced treble. Amount of details and resolution are not overwhelming but IEMs still sound clear and have well defined instrument spacing and their layering. Nothing gets lost in the mix, each small detail is present. Stage depth and width are moderate but not too tight. I would say that those IEMs belong to 70-120$ single DD class, no more and no less. Perhaps, the least detailed here is the treble – lack of lightweight airiness and slight tendency to hisses. Although, this is compensated by the overall good balance and its timbre which make those IEMs sound natural and immersive. Was surprised how good it handled most of the music genres, including rap and hiphop, but noticed a bit of harsh high notes in heavy metal.

DAC/AMP SoC on its own is unexpectedly powerful for the bundled pair of IEMs – even 30% volume is quite a lot. I even tried Hidizs MP143 planars to pair with it and IEMs felt decent with this level of power output. Didn’t notice any obvious coloration or accents in comparison to Hidizs AP80 player – quite close. The only difference is that AP80 DAP is pushing slightly more noticeable texturing across the ranges and a little bit more delicate on treble. Such details are only apparent after long A/B testing in quiet surroundings, not on the go as intended by Nebula nature.
HD mic works fine on my Xiaomi smartphone but I wished that it would be a little more sensitive and less prone to incoming noises. It captures voice clear and loud indoors but might suffer from the surrounding environment and rubbing against clothes outside.

Conclusion:
Hidizs ST2 Nebula is good, convenient and universal bundle of IEMs and type-C DAC/AMP designed to be used with most of type-C equipped devices, no matter indoors or on the go. IEMs are both – comfortably tuned and ergonomically fit while DAC is cross-compatible between different OS, devices and IEMs, as well as powerful enough to drive even more demanding planars. Therefore, buying such bundle we get 2 devices at once that can be used independently. But I like the synergy it produces as a bundle and the intention of Hidizs to create the balance between the connectivity, sound quality and convenience of everyday use of this combo. I would leave my planars and DAP for more dedicated listening while ST2 Nebula bundle can join my smartphone when I leave home.
Hidizs is giving away ST2 Nebula bundle : LINK
You can get the least price and support this product on Kickstarter: LINK