Greetings!
Today we're checking out a modern update to a classic KZ.
The original ZST was a landmark product and KZ's first foray into hybrid earphones. It inspired an entire segment of equally budget-friendly hybrid competitors, a market that today is alive and well, teeming with new models. Prior to the release of the ZST, fans of the brand had been relentlessly asking KZ to dip their toes into the hybrid market. The consensus seemed to be that KZ had no intention of doing so. Balanced armatures (BAs) were still too pricey, meaning their implementation would drive the price above the market KZ was dominating and comfortable in. Times have clearly changed. Hybrids are now KZ's bread and butter with pure dynamic based earphones being a rarity, their release outpaced even by pure-armature models.
The ZST X revives the ZST name while also retaining key features and characteristics of the original; 1+1 hybrid, low profile shell, low price, and removable 2-pin cables. Is it a worthy successor to the landmark product that was the ZST? Let's find out.
What I Hear The ZST X is a welcome update to the original ZST with one change in particular that elevates it over it's predecessor.
Treble is one area where the two differ most. Upper treble is pretty similar with both offering a decent amount of sparkle and air between notes. The ZST X's newer drivers do sound a bit smoother and more refined. Leading into the low treble is where the two separate, and the ZST X comes into it's own. The 4K rise of the ZST X brings in plenty of detail and clarity for a budget offering. The original ZST falls far behind in this regard giving listeners a lower resolution, more analogue-like sound. I also find the ZST X to sound quite quick with a rapid attack and equally snappy decay.
The mids of the ZST X are very crisp and coherent with a fairly equal representation for male and female vocals. Note weight is moderate, with a more lean, moderately brighter sound than the original ZST. The ZST X has great clarity with a solid ability to pull micro-detail. It is certainly a step up from it's predecessor which comes across overly smooth and lacking in fine detail in comparison. Timbre on neither is completely accurate with the ZST X having the advantage. While a touch bright, it is lacking the artificial edge pasted across most of the ZST's auditory spectrum.
Bass on the two is very similar in terms of balance and linearity when transitioning from sub-bass regions and up into the lower mids. The ZST X's low end is even more elevated than the original ZST, bringing along with it additional texture. Note control is also quite good for a budget earphone with no sloppiness or bloat to speak of, except on tracks that are particularly mid-bassy. Extension is excellent with sub-bass notes providing plenty of physical feedback. The original ZST falls behind here too. The ZST X's ability to handle congested tracks is good, but tossing the rapid double bass common to speed metal trips it up. The original ZST doesn't fall far behind. Texturing on the ZST X is also quite good but falls short of the best-in-class. The original ZST is overshadowed.
When it comes to sound stage the ZST X provides a decently spacious experience that keeps up with other products in this price range. I find the staging deeper than it is wide with excellent layering and good instrument separation. Imaging is quite satisfying with fairly nuanced channel-to-channel movement. They work fine for gaming, but I wouldn't reply on them for pinpoint accuracy. In comparison, the original ZST sounds a little wider but not nearly as deep. Its imaging is more vague and lacking the same level of accuracy. The ZST doesn't layer as well either, nor are instruments as well separated. Staging qualities are where the ZST truly shows it age and is most outclassed.
Overall I find the ZST X to be a pretty significant upgrade on a technical level. It's staging qualities are notably better and it's detail retrieval and clarity are vastly improved. That said, I quite enjoy the ZST's smooth sound and fairly relaxed presentation and can see some preferring it to the Xs more lively sound.
Compared To A Peer (volumes matched with Dayton iMM-6)
KZ ZS4 (~18 USD): The ZS4 is a quite a bit more v-shaped and bassy than the already bassy ZST X. Both models bias towards sub-bass with excellent extension, with the ZST X sounding more linear as you head into the lower mids. The ZS4's low end is a bit smoother and slower sounding than the ZSTX which better handles quick notes. It also feels more textured though the differences are minimal. Mids on the ZST X are more weighty and forward with less of a rise heading into the upper mids. I actually find the ZS4 to sound slightly more timbre-accurate with the ZST X applying a wooden, blunted edge to some instruments. That said, vocals on the ZS4 do have a somewhat breathy quality to them which may bother some. Heading into the treble, the ZS4 has a clear bias towards the brilliance region making it quite a bit more sparkly and vibrant. It really highlights the v-shaped signature. The dip in the presence region also put it at a significant disadvantage in terms of detail output. In terms of sibilance, I hear it on both. It appears more often on the ZS4, but the ZST X's is sharper and more unpleasant. Sound stage is wider and deeper on the ZS4 but feels much less dynamic and more flat than what I hear from the ZST X. The ZST X offers better imaging, layering, and separation qualities too.
I appreciate the raised mids, improved technical ability, and overall more even sound of the ZST X. The ZS4's abundant low end is pretty fun though, and I like the shells a lot, even if they're not quite as comfortable as the ZST X's tried and true shape.
KB EAR KB04 (~30 USD): Comparisons to the KB04 are very similar to the ZS4. The KB EAR is notably bassier but like the ZST X has a sub-bass bias. While the bass performance in the ZST X is good, the KB04 is even tighter and punchier. That could come down to the driver tech, the dense metal housings, or a combination of the two. The KB04 has even better texturing too. Heading into the mids the ZST X pulls itself back into contention. While they both have a bump to upper mid emphasis, the ZST X's rise is more gradual and retains a more linear emphasis through into the treble regions. Along with being less fatiguing, the ZST X's timbre is more accurate, missing the dry, crispy nature of the KB04. Treble presentation is similar but I prefer the ZST X. Notes are a bit thicker, tighter, and better controlled with less overall emphasis that is more effectively balanced out by the abundant low end. Sound stage on the ZST X is a little bit wider and deeper with similar imaging quality. The KB04 offers up slightly improved layering and instrument separation.
Overall I prefer the less aggressively v-shaped sound of the ZST X. It's not as well built but it's a lot lighter, more ergonomic and comfortable, and as a budget friendly all-rounder is simply more enjoyable to use.
In The Ear The ZST X is built the same as the original ZST, more or less. Higher quality acrylics have been employed for the main body and face plate with the completely clear design mimicking that of the purple ZST Colourful that came out later in the earphone's lifespan. While I prefer the somewhat cheesy looking faux carbon-fibre face plate on the earliest ZST models, the simpler design of the new X version looks nice. Unlike the ZST X's more expensive counsins (ZSN, ZSN Pro, ZSN Pro X) the 2-pin ports are not screwed in place. Instead the somewhat complicated inner moulding keeps everything where it needs to be. The plastic nozzles of the original ZST make a return and do a fine job of holding most standard sized tips securely in place. All together, the ZST X ends up looking and feeling quite decent, especially given the low price tag.
The cable is a straight upgrade from previous KZs, including the similar looking silver-plated cable that was available as an upgrade. The sheath is thicker, more plush, and less prone to tangling above the y-split. The silver-plated wiring within has a nice sheen to it too. It looks and feels quite nice. The hardware falls into the “same old, same old” category though. The VSonic inspired y-split and jack carry over from earlier KZ's, as do the excellent preformed ear guides. Overall a great stock cable and quite welcome on a budget model.
Comfort is outstanding for me. This earpiece has been a staple across a couple brands in my experience with mild tweaks being made to the nozzle angle and quality of the plastics. With the ZST X, it fits perfectly with little to no effort required to get and maintain a good seal. The super lightweight, all-plastic design works in it's favour too. The preformed guides hold the cable securely around the ear resulting in an earphone that is very stable under extreme movement. If you have small outer ears or they're a particularly odd shape you might have issues with fit and comfort, but I expect everyone else to find these a pleasant product to wear.
Isolation is basically the same as the original ZST based on my time with the two products. Any differences are hardly noticeable. With no music on and a Youtube video playing on my laptop in the background at my normal listening volumes, everything was still audible and I could follow along, but just barely. Using them in my local coffee shop requires a mild increase in volume to compensate, but nothing extreme. In general, bringing music into the equation makes outside noise a non-issue, especially if you opt to toss on some third party foam tips.
In The Box The ZST X arrives in the same style of packaging as the majority of KZ’s modern offerings. The white exterior sheath features a coloured digital rendering of the ZST X's ear pieces as well as model info, while on the back you find specifications as well as locations and contact information for KZ. Sliding off the sheath reveals the ZST X's ear pieces set within a paper covered foam insert protected by a clear viewing lid. Lifting it all out you find the accessories below. In all you get:
Final Thoughts Overall I find the ZST X a fantastic update to the original ZST, and a very suitable replacement. It keeps what was great about the original model, namely the comfortable shell, then improves upon it in a number of areas; detail, clarity, bass extension and physical feedback, staging airiness and overall technical ability. That said, there are two other models in KZ's modern lineup that I would recommend picking up over the ZST X.
First is the EDX. At under 10 USD, it provides the same wearing experience thanks to it sharing a shell, though the ZST X comes with KZ's awesome new silver-plated cable. Sound wise they share pretty much the same signature with the ZST X providing more upper treble energy, detail, clarity. This comes at the expense of timbre which I find the EDX does better. The second I'd take over the ZST X is the DQ6. It once again offers a very similar signature but with all the peaks reduced. This leaves it more balanced and with more accurate timbre. It also looks and feels more premium thanks to the Zinc face plate, though the ZST shell is more comfortable. Well worth the increase in price in my opinion.
Would I recommend the ZST X? Yes, but with the caveat that the EDX and QD6 are unavailable to you. If that's the case, the ZST X is one of the better sub-20 USD earphones I've heard recently and makes for a great daily driver.
Thanks for reading!
- B9
Disclaimer A huge thanks to Lillian with Linsoul Audio for arranging a sample of the ZST X for the purposes of review. The thoughts within this review are my own subjective impressions based on months of time with the ZST X. They do not represent KZ, Linsoul, or any other entity. At the time of writing the ZST X was retailing for a mere 17.00 USD: https://www.linsoul.com/products/kz-zst-x
Specifications
Some Test Tunes
Supertramp – Crime of the Century
Slipknot – Vol 3 (The Subliminal Verses)
Daft Punk – Random Access Memories
Aesop Rock – The Impossible Kid
King Crimson – Lark's Tongues in Aspic
King Crimson – Starless and Bible Black
Infected Mushroom – Legend of the Black Shawarma
The Prodigy – The Day is My Enemy
Steely Dan – The Royal Scam
Porcupine Tree – Stupid Dreams
Fleetwood Mac – Rumors
Tobacco – screw*d Up Friends
Today we're checking out a modern update to a classic KZ.
The original ZST was a landmark product and KZ's first foray into hybrid earphones. It inspired an entire segment of equally budget-friendly hybrid competitors, a market that today is alive and well, teeming with new models. Prior to the release of the ZST, fans of the brand had been relentlessly asking KZ to dip their toes into the hybrid market. The consensus seemed to be that KZ had no intention of doing so. Balanced armatures (BAs) were still too pricey, meaning their implementation would drive the price above the market KZ was dominating and comfortable in. Times have clearly changed. Hybrids are now KZ's bread and butter with pure dynamic based earphones being a rarity, their release outpaced even by pure-armature models.
The ZST X revives the ZST name while also retaining key features and characteristics of the original; 1+1 hybrid, low profile shell, low price, and removable 2-pin cables. Is it a worthy successor to the landmark product that was the ZST? Let's find out.
What I Hear The ZST X is a welcome update to the original ZST with one change in particular that elevates it over it's predecessor.
Treble is one area where the two differ most. Upper treble is pretty similar with both offering a decent amount of sparkle and air between notes. The ZST X's newer drivers do sound a bit smoother and more refined. Leading into the low treble is where the two separate, and the ZST X comes into it's own. The 4K rise of the ZST X brings in plenty of detail and clarity for a budget offering. The original ZST falls far behind in this regard giving listeners a lower resolution, more analogue-like sound. I also find the ZST X to sound quite quick with a rapid attack and equally snappy decay.
The mids of the ZST X are very crisp and coherent with a fairly equal representation for male and female vocals. Note weight is moderate, with a more lean, moderately brighter sound than the original ZST. The ZST X has great clarity with a solid ability to pull micro-detail. It is certainly a step up from it's predecessor which comes across overly smooth and lacking in fine detail in comparison. Timbre on neither is completely accurate with the ZST X having the advantage. While a touch bright, it is lacking the artificial edge pasted across most of the ZST's auditory spectrum.
Bass on the two is very similar in terms of balance and linearity when transitioning from sub-bass regions and up into the lower mids. The ZST X's low end is even more elevated than the original ZST, bringing along with it additional texture. Note control is also quite good for a budget earphone with no sloppiness or bloat to speak of, except on tracks that are particularly mid-bassy. Extension is excellent with sub-bass notes providing plenty of physical feedback. The original ZST falls behind here too. The ZST X's ability to handle congested tracks is good, but tossing the rapid double bass common to speed metal trips it up. The original ZST doesn't fall far behind. Texturing on the ZST X is also quite good but falls short of the best-in-class. The original ZST is overshadowed.
When it comes to sound stage the ZST X provides a decently spacious experience that keeps up with other products in this price range. I find the staging deeper than it is wide with excellent layering and good instrument separation. Imaging is quite satisfying with fairly nuanced channel-to-channel movement. They work fine for gaming, but I wouldn't reply on them for pinpoint accuracy. In comparison, the original ZST sounds a little wider but not nearly as deep. Its imaging is more vague and lacking the same level of accuracy. The ZST doesn't layer as well either, nor are instruments as well separated. Staging qualities are where the ZST truly shows it age and is most outclassed.
Overall I find the ZST X to be a pretty significant upgrade on a technical level. It's staging qualities are notably better and it's detail retrieval and clarity are vastly improved. That said, I quite enjoy the ZST's smooth sound and fairly relaxed presentation and can see some preferring it to the Xs more lively sound.
Compared To A Peer (volumes matched with Dayton iMM-6)
KZ ZS4 (~18 USD): The ZS4 is a quite a bit more v-shaped and bassy than the already bassy ZST X. Both models bias towards sub-bass with excellent extension, with the ZST X sounding more linear as you head into the lower mids. The ZS4's low end is a bit smoother and slower sounding than the ZSTX which better handles quick notes. It also feels more textured though the differences are minimal. Mids on the ZST X are more weighty and forward with less of a rise heading into the upper mids. I actually find the ZS4 to sound slightly more timbre-accurate with the ZST X applying a wooden, blunted edge to some instruments. That said, vocals on the ZS4 do have a somewhat breathy quality to them which may bother some. Heading into the treble, the ZS4 has a clear bias towards the brilliance region making it quite a bit more sparkly and vibrant. It really highlights the v-shaped signature. The dip in the presence region also put it at a significant disadvantage in terms of detail output. In terms of sibilance, I hear it on both. It appears more often on the ZS4, but the ZST X's is sharper and more unpleasant. Sound stage is wider and deeper on the ZS4 but feels much less dynamic and more flat than what I hear from the ZST X. The ZST X offers better imaging, layering, and separation qualities too.
I appreciate the raised mids, improved technical ability, and overall more even sound of the ZST X. The ZS4's abundant low end is pretty fun though, and I like the shells a lot, even if they're not quite as comfortable as the ZST X's tried and true shape.
KB EAR KB04 (~30 USD): Comparisons to the KB04 are very similar to the ZS4. The KB EAR is notably bassier but like the ZST X has a sub-bass bias. While the bass performance in the ZST X is good, the KB04 is even tighter and punchier. That could come down to the driver tech, the dense metal housings, or a combination of the two. The KB04 has even better texturing too. Heading into the mids the ZST X pulls itself back into contention. While they both have a bump to upper mid emphasis, the ZST X's rise is more gradual and retains a more linear emphasis through into the treble regions. Along with being less fatiguing, the ZST X's timbre is more accurate, missing the dry, crispy nature of the KB04. Treble presentation is similar but I prefer the ZST X. Notes are a bit thicker, tighter, and better controlled with less overall emphasis that is more effectively balanced out by the abundant low end. Sound stage on the ZST X is a little bit wider and deeper with similar imaging quality. The KB04 offers up slightly improved layering and instrument separation.
Overall I prefer the less aggressively v-shaped sound of the ZST X. It's not as well built but it's a lot lighter, more ergonomic and comfortable, and as a budget friendly all-rounder is simply more enjoyable to use.
In The Ear The ZST X is built the same as the original ZST, more or less. Higher quality acrylics have been employed for the main body and face plate with the completely clear design mimicking that of the purple ZST Colourful that came out later in the earphone's lifespan. While I prefer the somewhat cheesy looking faux carbon-fibre face plate on the earliest ZST models, the simpler design of the new X version looks nice. Unlike the ZST X's more expensive counsins (ZSN, ZSN Pro, ZSN Pro X) the 2-pin ports are not screwed in place. Instead the somewhat complicated inner moulding keeps everything where it needs to be. The plastic nozzles of the original ZST make a return and do a fine job of holding most standard sized tips securely in place. All together, the ZST X ends up looking and feeling quite decent, especially given the low price tag.
The cable is a straight upgrade from previous KZs, including the similar looking silver-plated cable that was available as an upgrade. The sheath is thicker, more plush, and less prone to tangling above the y-split. The silver-plated wiring within has a nice sheen to it too. It looks and feels quite nice. The hardware falls into the “same old, same old” category though. The VSonic inspired y-split and jack carry over from earlier KZ's, as do the excellent preformed ear guides. Overall a great stock cable and quite welcome on a budget model.
Comfort is outstanding for me. This earpiece has been a staple across a couple brands in my experience with mild tweaks being made to the nozzle angle and quality of the plastics. With the ZST X, it fits perfectly with little to no effort required to get and maintain a good seal. The super lightweight, all-plastic design works in it's favour too. The preformed guides hold the cable securely around the ear resulting in an earphone that is very stable under extreme movement. If you have small outer ears or they're a particularly odd shape you might have issues with fit and comfort, but I expect everyone else to find these a pleasant product to wear.
Isolation is basically the same as the original ZST based on my time with the two products. Any differences are hardly noticeable. With no music on and a Youtube video playing on my laptop in the background at my normal listening volumes, everything was still audible and I could follow along, but just barely. Using them in my local coffee shop requires a mild increase in volume to compensate, but nothing extreme. In general, bringing music into the equation makes outside noise a non-issue, especially if you opt to toss on some third party foam tips.
In The Box The ZST X arrives in the same style of packaging as the majority of KZ’s modern offerings. The white exterior sheath features a coloured digital rendering of the ZST X's ear pieces as well as model info, while on the back you find specifications as well as locations and contact information for KZ. Sliding off the sheath reveals the ZST X's ear pieces set within a paper covered foam insert protected by a clear viewing lid. Lifting it all out you find the accessories below. In all you get:
- ZST X earphones
- 0.75mm 2-pin silver-plated braided cable
- Starline silicone tips (s/m/l)
- Manual and warranty card
Final Thoughts Overall I find the ZST X a fantastic update to the original ZST, and a very suitable replacement. It keeps what was great about the original model, namely the comfortable shell, then improves upon it in a number of areas; detail, clarity, bass extension and physical feedback, staging airiness and overall technical ability. That said, there are two other models in KZ's modern lineup that I would recommend picking up over the ZST X.
First is the EDX. At under 10 USD, it provides the same wearing experience thanks to it sharing a shell, though the ZST X comes with KZ's awesome new silver-plated cable. Sound wise they share pretty much the same signature with the ZST X providing more upper treble energy, detail, clarity. This comes at the expense of timbre which I find the EDX does better. The second I'd take over the ZST X is the DQ6. It once again offers a very similar signature but with all the peaks reduced. This leaves it more balanced and with more accurate timbre. It also looks and feels more premium thanks to the Zinc face plate, though the ZST shell is more comfortable. Well worth the increase in price in my opinion.
Would I recommend the ZST X? Yes, but with the caveat that the EDX and QD6 are unavailable to you. If that's the case, the ZST X is one of the better sub-20 USD earphones I've heard recently and makes for a great daily driver.
Thanks for reading!
- B9
Disclaimer A huge thanks to Lillian with Linsoul Audio for arranging a sample of the ZST X for the purposes of review. The thoughts within this review are my own subjective impressions based on months of time with the ZST X. They do not represent KZ, Linsoul, or any other entity. At the time of writing the ZST X was retailing for a mere 17.00 USD: https://www.linsoul.com/products/kz-zst-x
Specifications
- Frequency Response: 20-40,000Hz
- Impedance: 12 ohms
- Sensitivity: 107dB/mW
- Cable: 0.75mm 2-pin
- Driver: One balanced armature, one dynamic per side
Some Test Tunes
Supertramp – Crime of the Century
Slipknot – Vol 3 (The Subliminal Verses)
Daft Punk – Random Access Memories
Aesop Rock – The Impossible Kid
King Crimson – Lark's Tongues in Aspic
King Crimson – Starless and Bible Black
Infected Mushroom – Legend of the Black Shawarma
The Prodigy – The Day is My Enemy
Steely Dan – The Royal Scam
Porcupine Tree – Stupid Dreams
Fleetwood Mac – Rumors
Tobacco – screw*d Up Friends
Jimmyblues1959
Just bought a pair. Great review!
This review originally appeared on my blog.
Nobody releases earphones as frequently as KZ does.
Even the past week they probably released one or two of them, and that’s not even counting their sister-brand CCA who also has their own releases. Saturate the market so much that no matter what people look for it’s your product they end up with. It’s a business strategy that’s not possible unless you follow a specific “no R&D, just buy off-the-shelf stuff and paste your sticker on them” mantra that KZ almost pioneered in a sense.
The ZST X is the upgrade to their (very popular) ZST model. The driver config is the same (1DD + 1BA) but the dynamic driver seems to have been upgraded. Also the accessories have seen a nice face-lift without adding much to the price-tag. Let’s see if we can find a budget gem in here.
Note: the ratings given will be subjective to the price tier. The ZST X was a review unit. Disclaimer
Sources used: LG G7, iPhone SE
Price, while reviewed: $15.
Build: Call it resin, call it plastic — it’s the same old 3D-printed shell that common across approximately 23518 different IEMs. It doesn’t look gaudy unlike certain recent releases and I quite like the bottle-green color-scheme so there’s that.
You can see both the single DD and the BA driver in the nozzle since the nozzle is also plastic, unlike the metal nozzles in most such models (though the dust-filter is metal). The model name “ZST X” is printed in large cursive fonts on the back of the IEM. There are no channel markings anywhere surprisingly so be a bit careful while attaching the wire. There is a single vent-hole on the inner-side and it’s enough to alleviate driver-flex. The connectors are slightly recessed 2-pin and has a snug-fit with the supplied cable.
4/5
Accessories: The basics are covered, and they are covered well. You get the very nice Starline tips along with a “SPC” cable (though I’m fairly certain it’s not Silver there, Tin plated would be more accurate). Nonetheless, the SPC cable is a massive improvement over old KZ cables (which was an ergonomic nightmare and of poor quality in general). You don’t need to replace it at all and you’re good to go right out of the box. There ain’t any carrying case but for that price I’ll let it slide.
4.5/5
Comfort/Isolation: The fit and general comfort of the ZST X is very good. It’s lightweight, has no sharp edges and can be worn for long hours. Isolation is below-average with the Starline tips however.
4/5
Now, onto the sound.
The KZ ZST X is a single dynamic + single balanced-armature driver hybrid IEM. The 10mm PET diaphragm driver is taking care of the bass (and perhaps the lower-mids) whereas the 30095 BA driver is taking care of the upper frequencies. It’s a setup we’ve seen a thousand times by now and I’ve always been less than impressed with the sound more often than not.
The general sound signature is V-shaped with a very sizable bass-boost and recessed lower-midrange. There is the usual 2KHz and 4KHz peaks (a default “signature” of many chi-fi offerings) but the latter lower-treble peak is less aggressive in comparison and thus doesn’t sound as piercing. In short: a very on-your-face tuning that falls just short of aggressive.
Bass: The ZST X gets a very prominent sub-bass boost that starts right below 100Hz and goes climbing until 20Hz. The sub-bass is boosted by at least 5/6dB over the mid-bass, so a lot of the bass-texture is lost in the process. It is a punchy listen though, and won’t bother you if you’re mostly after extension and punch instead of texture and subtlety. Bass isn’t too invasive and doesn’t bleed much into the lower-mids. In fact, the mids sound detached from the lows, giving rise to tonal incoherency. Then again, I should probably not complain much about these in a cheap hybrid.
To summarize: punchy, plentiful bass. Should satisfy most unless you need even more bass or severely reduced/more linear bass.
4/5
Mids: The midrange is thin, borders on shoutiness and has a colored tonality that focuses on upper-harmonics. Male vocals lack heft and fullness, so does lower-octave notes. Female vocals are put on the forefront and can get intense (e.g. certain Avril Lavigne songs). However, higher-pitched string instruments sound crisp with well-defined attack, so not all is lost. Timbre is wrong, but not overly so. Detail retrieval is above-average for the price-class (<$20).
This is not a neutral or natural midrange, but if you’re after an exciting presentation without much regard for accuracy this will serve you well.
3.5/5
Treble: Treble is mostly muted past the initial 4KHz spike. Cymbal hits aren’t emphasized and can even sound muted/lifeless based on track/mastering. Treble decay is unnaturally quick, with cymbal hits often disappearing into the void without exhibiting resonance. I’m not complaining much though as it’s miles better than piercing treble spikes, sibilance or straight-out treble harshness. There isn’t any upper-treble extension to speak of. The ZST X doesn’t offend in particular, and that’s a better compliment than I can give to most cheap hybrids.
3.5/5
Soundstage: Soundstage is closed-in, with average width and height. Stage depth is quite good for the price though. It’s in fact one of the highlights of this IEM.
4/5
Imaging: Imaging is pretty good thanks to the above-average stage-depth. It doesn’t quite get the ordinal imaging correct (top-left, bottom-right etc.) but it’s a weakness of even many (hyped) $100 IEMs so it’s acceptable. Instrument separation and layering is also good, a cut above most hybrids in this price-bracket. It can get hazy in faster/busier tracks but given the pricing (again) I don’t see the point of nitpicking.
4/5
Bang-for-buck: The KZ ZST X faces still competition in this price bracket but most of the cheap hybrids are really poorly tuned and doesn’t come with any half-decent accessories. In fact, all the IEMs I can think of that are noticeably better cost $25 at least.
The ZST X has a colored but not too offensive tuning and isn’t as fatiguing as most other budget hybrids. The provided accessories are also good enough and won’t need replacing (unlike, say, BLON BL-03/05). I’d say it’s definitely worth the price if you’re after a V-shaped signature.
4/5
Source and Amplification: It runs off of everything and gets loud quite easily. Mobile devices or cheap DAPs/BT dongles/DAC dongles — nothing matters. As long as the source has a clean enough output, you’re good to go.
Select Comparisons
vs KBEar KB04 ($25): The KB04 has better bass, similar mids and more fatiguing treble. It’s built better, costs almost twice as much. It does resolve significantly more detail and also has better upper-treble reach with superior imaging/similar staging. KB04 is still the best budget hybrid I’ve tried till date, but the ZST X does most of the things at a cheaper price.
vs Moondrop Spaceship ($20): The Moondrop Spaceship hits close to the diffused-field target response and thus has more anemic bass and slightly shoutier upper-mids. It’s also more resolving, has more air in the upper-treble and generally more reference tuning. Unfortunately, it needs a lot of power to drive properly and the source you need to have to run these are far more expensive than the IEMs themselves. Also, the cable is non-detachable and if that bothers you, ZST X is the better choice.
vs Final E500 ($25): The E500 has a smoother sound and can sound phenomenal on binaural tracks/live tracks/games/movies. In regular joint-stereo tracks does it loses some of its shine. It’s a specialist IEM that has a great tuning and tonality along with spectacular imaging. It’s biggest issue: availability. It’s a lot harder to come across and might involve ordering from abroad. Sigh.
Conclusion
KZ has been (rightly) criticized for their rapid-fire releases that mostly sound similar/same and at times: worse than the model it’s supposed to replace *cough* ZS6 *cough*.
The ZST X, fortunately, is a wholesale upgrade over the model it replaces (KZ ZST). It’s also a very good choice in the <$20 bracket if you’re comfortable with the V-shaped signature (and upper-mid emphasis). It’s cheap, it ain’t shabby, and for the price (that dreaded word) — I don’t find any deal-breaking flaw.
Overall Rating: 2.5/5
Review test tracks: https://tidal.com/browse/playlist/04350ebe-1582-4785-9984-ff050d80d2b7
Introduction :
KZ also known for making “Super Budget” IEMs are famous for their price to performance ratio. KZ Acoustics was founded in 2013 with a simple goal to provide good sound at relatively less price. It’s one of the most famous “Chi-Fi” IEM makers and they push multi hybrid setups every few months. KZ gained a lot of popularity after their release of KZ ZST and ZS10 Pro which sounded much fuller than its competitors.
Disclaimer :
The review was tested at 24$ (16$ Now) and all the judgement was made keeping the exact same price in mind. We're not responsible for any price change that might alter this review.
The item was purchased from Amazon.in (Indian region) from our own money.
Purchasable link :
Linsoul.
Headphone Zone (India).
Specifications :
Unboxing and Accessories :
KZ unboxing was small and the presentation was on point. On the outer cover, ZSTx are made with the respective color inside, on the back of the cover there are specifications. After removing the cover you have an actual box in which ZSTx are sitting tightly in foam. Beneath the foam you have a KZ Silver wire, Starline tips (S/M/L) and a documentation to support the monitors.
Cable :
Cable that comes with the box is a 3.5mm unbalanced cable. It’s a 2 pin (0.75) qdc connector which is silver in color. Y split has a transparent boxy shape and it doesn’t have any chin slider. There are no microphonics. The cable braiding is good and tight. If you ever wish to upgrade cable, make sure to use a qdc cable. The cable is amazing for its price. It uses a “L-type” termination jack.
IEM Quality and fit :
ZSTx are made out of basic semi-transparent plastic. It comes in two colors, Purple and Cyan and both of them look good at the price they come in. They have ZSTx printed on the faceplate with silver colour which is prone to chipping. We saw ZSTx fading in our unit. They are very light weight and you don’t even feel them in your ear. The fit is good and comfortable but they do stick out of the ears just slightly.
Sound Isolation :
ZSTx are made out of plastic shell and to no surprise, they fail to block outside noise. With the right seal and enough volume it’s definitely hard to hear outside noise. Sound isolation can be improved with the right tips on this pair.
The Driveability and sources used :
KZ ZSTx is very easy to drive, so much so that you can overdrive them very easily even on low gain. It can be paired with any phone perfectly with only 12 Ohm impedance. It’s one of the easiest to drive IEMs. We have tried different DAPs and sources but sound remained the same throughout the testing.
Sources used are:
The Sound (3.5/5) :
Bass (4.5/5) :
As mentioned these pair of IEMs are a fun sounding hence the bass is punchy and on a boomy side due to which some times bleeds into the mids resulting in bass over powering but nothing disappointing, the sub bass is present but does not actually have the authority as heard in the Blon BL03 that said KZ did outperform the other KZ products in the bass region in this price range or above, not a basshead iem but can easily pass as fun sound in terms of bass, lacks a proper articulation or control on the bass but is fast in terms of response and one would actually love these for the bass kick that is present.
Mids (4.5/5) :
The actual selling point for these are the way these handle the mids, they are absolute delight in this price range, they are slightly V curved which actually rolls of the lower mids perfectly to depict a more lively presence of artist and the vocal representation is what amazed us, the way the vocals are resolved, it is a surprising phenomenon under the 20$ price range. Male and female vocals do sound close to real reproduction and does not feel thin at any given point which again in the price is amazing to achieve.
Treble (3.0/5) :
Treble is what breaks this product on scoring high. The sharpness of treble weighs down the entire spectrum. It’s biting and fatiguing and at same times feels unnatural on many tracks like “You and your friend from Dire Straits” the drumming sticks sounds very sharp which feels very unnatural. The wrong crossover design or BA selection is the main culprit of it, KZ would’ve achieved a very smooth overall tonality with better tuning.
Soundstage :
Soundstage is narrow with average depth and height. You can hear left to right cues, thanks to it’s decent separation. It is not congested nor it feels gigantic, it’s there but minimal. At this price point, it’s performing like it should and soundstage is not an issue.
Imaging :
Imaging is good and you can make out the position of every instrument in space quite easily. With many instruments coming in together, it does get overlapping sometimes but it’s acceptable at this price point. “Whole Lotta Love from Led Zeppelin” shows an example of average imaging where hi-hat at 1:25 lacks precision.
Tracks used:
KZ ZSTx is a wonderful pair coming in at just 16$. It comes with everything out of the box and you don’t have to spend anything extra on upgradations like wire and tips. It is sibilant on almost all tracks with higher volume, if you’re someone who likes to listen to music fully cranked up, this might be too sharp for your ears. But do remember it is a very bright sounding IEM. With 10$ more you can get Blon BL03 which we think is a serious upgrade from this pair in every possible way, although you do have to buy a new cable and tips with Blon.
KZ also known for making “Super Budget” IEMs are famous for their price to performance ratio. KZ Acoustics was founded in 2013 with a simple goal to provide good sound at relatively less price. It’s one of the most famous “Chi-Fi” IEM makers and they push multi hybrid setups every few months. KZ gained a lot of popularity after their release of KZ ZST and ZS10 Pro which sounded much fuller than its competitors.
Disclaimer :
The review was tested at 24$ (16$ Now) and all the judgement was made keeping the exact same price in mind. We're not responsible for any price change that might alter this review.
The item was purchased from Amazon.in (Indian region) from our own money.
Purchasable link :
Linsoul.
Headphone Zone (India).
Specifications :
Unboxing and Accessories :
KZ unboxing was small and the presentation was on point. On the outer cover, ZSTx are made with the respective color inside, on the back of the cover there are specifications. After removing the cover you have an actual box in which ZSTx are sitting tightly in foam. Beneath the foam you have a KZ Silver wire, Starline tips (S/M/L) and a documentation to support the monitors.
Cable :
Cable that comes with the box is a 3.5mm unbalanced cable. It’s a 2 pin (0.75) qdc connector which is silver in color. Y split has a transparent boxy shape and it doesn’t have any chin slider. There are no microphonics. The cable braiding is good and tight. If you ever wish to upgrade cable, make sure to use a qdc cable. The cable is amazing for its price. It uses a “L-type” termination jack.
IEM Quality and fit :
ZSTx are made out of basic semi-transparent plastic. It comes in two colors, Purple and Cyan and both of them look good at the price they come in. They have ZSTx printed on the faceplate with silver colour which is prone to chipping. We saw ZSTx fading in our unit. They are very light weight and you don’t even feel them in your ear. The fit is good and comfortable but they do stick out of the ears just slightly.
Sound Isolation :
ZSTx are made out of plastic shell and to no surprise, they fail to block outside noise. With the right seal and enough volume it’s definitely hard to hear outside noise. Sound isolation can be improved with the right tips on this pair.
The Driveability and sources used :
KZ ZSTx is very easy to drive, so much so that you can overdrive them very easily even on low gain. It can be paired with any phone perfectly with only 12 Ohm impedance. It’s one of the easiest to drive IEMs. We have tried different DAPs and sources but sound remained the same throughout the testing.
Sources used are:
- iBasso DX120
- Shanling M0
- iPhone with lightning to 3.5 adapter
The Sound (3.5/5) :
Bass (4.5/5) :
As mentioned these pair of IEMs are a fun sounding hence the bass is punchy and on a boomy side due to which some times bleeds into the mids resulting in bass over powering but nothing disappointing, the sub bass is present but does not actually have the authority as heard in the Blon BL03 that said KZ did outperform the other KZ products in the bass region in this price range or above, not a basshead iem but can easily pass as fun sound in terms of bass, lacks a proper articulation or control on the bass but is fast in terms of response and one would actually love these for the bass kick that is present.
Mids (4.5/5) :
The actual selling point for these are the way these handle the mids, they are absolute delight in this price range, they are slightly V curved which actually rolls of the lower mids perfectly to depict a more lively presence of artist and the vocal representation is what amazed us, the way the vocals are resolved, it is a surprising phenomenon under the 20$ price range. Male and female vocals do sound close to real reproduction and does not feel thin at any given point which again in the price is amazing to achieve.
Treble (3.0/5) :
Treble is what breaks this product on scoring high. The sharpness of treble weighs down the entire spectrum. It’s biting and fatiguing and at same times feels unnatural on many tracks like “You and your friend from Dire Straits” the drumming sticks sounds very sharp which feels very unnatural. The wrong crossover design or BA selection is the main culprit of it, KZ would’ve achieved a very smooth overall tonality with better tuning.
Soundstage :
Soundstage is narrow with average depth and height. You can hear left to right cues, thanks to it’s decent separation. It is not congested nor it feels gigantic, it’s there but minimal. At this price point, it’s performing like it should and soundstage is not an issue.
Imaging :
Imaging is good and you can make out the position of every instrument in space quite easily. With many instruments coming in together, it does get overlapping sometimes but it’s acceptable at this price point. “Whole Lotta Love from Led Zeppelin” shows an example of average imaging where hi-hat at 1:25 lacks precision.
Tracks used:
- XXXTentacion - “Jocelyn Flores” For male vocals.
- Dr. Chesky - “Transcendental Tripping” For soundstage.
- Led Zeppelin - “Whole Lotta Love” For soundstage and imaging.
- Run The Jewels - “Call Ticketron” For bass response and low end.
- The Marias - “I don’t know you” For female vocals.
KZ ZSTx is a wonderful pair coming in at just 16$. It comes with everything out of the box and you don’t have to spend anything extra on upgradations like wire and tips. It is sibilant on almost all tracks with higher volume, if you’re someone who likes to listen to music fully cranked up, this might be too sharp for your ears. But do remember it is a very bright sounding IEM. With 10$ more you can get Blon BL03 which we think is a serious upgrade from this pair in every possible way, although you do have to buy a new cable and tips with Blon.
KZ ZST X Review 
Fun and exciting listen
Best kz iem I have ever heard, replaces my fav kz zsr
V shaped sound signature
Slightly bright but not sibilant
Bass that hits and sounds good
Mids and vocals sound nice
Slight rolled off upper treble , slight dryness ,tiny peak around 2k
Awesome silver plated cable included
Excellent performer in its price range
Nothing ( off ) or that stopped me from listening for a long time.
Good workout iem
Alternative to vk4 if you want less bass and more detail in mids and highs.
Works well with phones , doesn’t need amp but they will add performance.
Fun and exciting listen
Best kz iem I have ever heard, replaces my fav kz zsr
V shaped sound signature
Slightly bright but not sibilant
Bass that hits and sounds good
Mids and vocals sound nice
Slight rolled off upper treble , slight dryness ,tiny peak around 2k
Awesome silver plated cable included
Excellent performer in its price range
Nothing ( off ) or that stopped me from listening for a long time.
Good workout iem
Alternative to vk4 if you want less bass and more detail in mids and highs.
Works well with phones , doesn’t need amp but they will add performance.
