LETSHUOER S15

INTRO
I recently had the pleasure of testing the Letshuoer S15, and I must say it left a lasting impression. As an avid audiophile, I'm always on the lookout for earphones that deliver a truly exceptional audio experience, and the S15 did not disappoint.

Disclaimer
I would like to thank @LetShuoer Audio and Ivy for arranging a unit for me. My opinions are unbiased, and I haven't been influenced or instructed to praise these IEMs. Every detail in this review is actual experience made by listening for hours everyday.


Packaging

The premium packaging comes with a high quality boxing with a slide out draw that holds three modular connector pins (2.5mm balanced, 3.5mm and 4.4mm balanced terminations) a cylinder containing an excellent modular cable. The two sets of silicone tips "Vocal ear tips" and "Balanced ear tips" The cable has an excellent quality and looks.

Comfort and Fit
Comfort is key during prolonged listening sessions, and the Letshuoer S15 excels in this aspect. The earphones come with a variety of ear tips, ensuring a snug fit for any ear shape. I found them comfortable even during extended use, making them suitable for daily commutes.



Sound Aspects

Source used :

Realme 9 Pro

Jcally AP7
Ibasso DC04 pro

This planar iems spend 50-60 hours of burn in before taking details of this review

Bass

The mid-bass it is forte, with quantity just enough when called. The quality of midbass is truly exceptional. The sub-bass is not the most extended, with a noticeable roll-off, resulting in no big rumble heard. It makes it up with solid texturing noted, with a punchy, fast and clean bass without any mid-bass bleed.

Midrange
It has a more forward midrange and also a more thick note weight. Like the bass, sounds linear and clean, allowing you to literally enjoy the lushness of vocals and instrumental layers. The warm tonality of this iem removes all the negative quality of a planar transducer.

Treble

The highs is airy and resolving, it has great treble extension without being bright or sounding overly pushed to get fake air. As for the lower part of the treble, it sounds smooth and relaxed. Not dull by any means, just a forgiving and musical treble presentation. The transducer has less to no metallic timbre makes you have more time to listen to.

Technicalities
The soundstage is quite impressive. Giving the S15 an extra juice will produce the sound out of your head and above average in term of wideness and tallness.

The imaging and layering is above average. The sound layering is great making a holographic macro dynamic experience, but it feels a bit foggy in background when bass is produce or midrange instrument like vocal take the lead the wide presence of it will give a slightly blur definition edge of other instrument in similar range. With instrumental musical like classical, the imaging is impressive.



Conclusion
The Letshuoer S15 delivers a top-notch audio experience with its comfortable build and design and impressive sound quality. The enjoyment and time you spend with it will justify the price it cost. If you're in the market for high-end earphones that prioritize audio fidelity and for prolonged listening session, the Letshouer S15 is undoubtedly worth considering.

Disclaimer:​

The Letshuoer S15 was sent to me as a review sample from Ivy from Letshourer, for which I thank!


I am very happy to be able to try their latest model, especially because I had the chance to try the S12 Pro, which I liked a lot. In this new one, several things have changed. We have their new technology, which adopts a sort of passive radiator/filter and a 3D-printed shell.

This time the price becomes interesting, or rather important, so I will try to carefully evaluate all aspects.


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:​

• Chassis Material: 3D printed resin
• Material of Faceplate: Anodized aluminum
• Frequency Response: 20Hz~40kHz
• Impedance: 30Ω
• Sensitivity: 106dB
• Audio connectors: 2.5mm, 3.5mm, and 4.4mm interchangeable connectors
• Cable: 1.2 m, 216-strand silver-plated monocrystalline copper
• Driver: 14.8mm planar driver + 6mm passive filtering module

Packaging:​

The packaging is exactly as I would have expected: very refined, elaborate, and pleasant to unbox. For a product in this price range, careful packaging is the minimum. You remove the external cardboard by sliding it and then, with a magnetic opening, you move on to its contents.


At first glance, we find a small letter with the warranty card, QC, and manual inside, which looks like a poster.


The accessories are in the drawer below, reminiscent of a jewelry box!


Inside, we find:

• Hard case
• Modular cable with 3 adapters 2.5mm, 3.5mm, and 4.4mm adapters
• 2 pairs of tips: Standard and Wide bore ear tips.

The included tips are of excellent quality; the wide-bore ones are spot on to improve the sound quality. Obviously, for such an expensive set, perhaps an extra set could have been useful; however, the ones included are the best possible. The cable is of the same material already seen on the S12 Pro and DZ4, and the fact that it is modular is excellent. I don’t doubt the quality of the cable but it is very rigid.


At the same time, it’s great because it doesn’t get tangled easily but it’s also a little uncomfortable in terms of comfort.

Design/Build quality:​

The Letshuoer S15 takes up the philosophy of the DZ4, and the materials are similar. The shell is 3D-printed resin by HeyGears, a well-known company in this sector. At first sight, you wouldn’t think it was 3D printed but with macro lenses, the layers are visible. The faceplate, on the other hand, is made of CNC-machined aluminum and the reason is probably the better resonance of the material. The construction is precise and well cared for, the dimensions are compact and the shape is comfortable. On the shell, we can see three ventilation holes.


Personally, I really liked the CNC-machined metal shell of the S12 PRO; same thing for the MP145 but Letshuoer has recently switched to producing shells with 3D printing. I’m not a sound engineer so I can’t tell you what’s best for the sound but certainly the S15, being made of resin, feels less cold in the ear. I know some are temperature sensitive and metal shell IEMs are downright cold in the winter.


Inside, we have reached the third generation of planar drivers, again 14.8mm but this time coupled with the R-sonic technology already seen on the DZ4, that is, the 6MM passive radiator/filter. I have read some complaints about it because its function as a passive radiator is not clear; in fact, it is more correct to talk about a passive filter. I’m not a sound expert or engineer, so it’s impossible for me to say whether this technology really works or not. To understand this, you should have a copy without this filter and compare them.

Comfort/Fit:​

Its comfort is very similar to that of the S12Pro; on the inside, they are quite similar, in my opinion. I think that as planar IEMS, they are the most compact ever, very light, and comfortable. The tips also help a lot in terms of comfort. Very good insulation from external noise. The only sore point is the slightly stiff cable. For my taste, it is of excellent quality but if it were slightly softer, it would be perfect.

Instagram 360 Overview

Letshuoer S15 360 clip

Initial sound impression:​

The Planar Driver was a discovery for me. Maybe the first IEMs weren’t up to the level of headphones but now the GAP has decreased a lot.


The ones in my possession are the S12 Pro, Hidizs Mp145, Kefine Klanar and the Hifiman He400Se. The S15 is definitely an improvement over the S12 Pro and will automatically become one of my favorites alongside the Hidizs MP145. The others all sound extremely good, except for the KZ PR2. I haven’t yet had the opportunity to try planars that sound bad. Generally, the performances are truly remarkable, and the Hidizs MP145 have become a reference for planar IEMs. The S15s sound just as good but differently. From the first listen, the Letshuoer S15 performs extremely well in terms of details, layering, and a significantly improved soundstage compared to the previous ones. I carefully performed several hours of burn-in to try again once finished.

Final sound impression:​

Equipment used for the testing above


Device:

• iMac
• Redmi Note 7 Snapdragon
• Poco M4 Pro Mediatek

Software:

• Foobar2000 24bit 192kHz (iMac)
• Amazon music UHD 24bit 96kHz (Both)
• Tidal Hifi Plus

DAC:​

• Moondrop Dawn Pro
• Moondrop Dawn 4.4
• Fosi SK02: Extra juice
• iBasso DC04pro : Most Used
• EPZ TP20 (Dual Cirrus)
• Hidizs S9 Pro Plus (ESS)
• EPZ TP30 (ESS)

My impressions are given using just the original accessories.


Nowadays, planar IEMs do not require an excessive amount to sound correctly, but their properties are at their best with DACs with a certain power reserve. Often, the sound is more open, acquiring dynamism and sometimes a slightly different depth. The Letshuoer S15 has all the connectors, but asking a mid-range phone to drive them at their best is a bit much. My POCO M4 Pro performs quite well but lacks the right boost that a DAC can give on balanced output.

Built in Technology:​

LETSHUOER S15 adds a 6mm passive filtering module outside the planar driver.




The passive filtering module is LETSHUOER’s in-house R-Sonic Dynamic Harmonic Technology. Positive filtering of sound energy through proprietary filters.

“R-Sonic Passive Filtering Module
To achieve a more natural and comfortable sound reproduction, LETSHUOER’s research and development team poured every ounce of their technical know-how into combining the 14.8mm dual chamber planar magnetic driver with LETSHUOER’s proprietary ‘R-Sonic’ PFM technology. Breaking through multiple technological barriers, the S15 is another outstanding entry into LETSHUOER’s planar earphone roaster, which delivers an unparalleled audio experience.
Dual Acoustic Tubes
The dual acoustic tubes filter the sound on different frequency bands, allowing the highs, mids, and lows to shine through proportionately and seamlessly. Every detail is carefully tuned, presenting an excellent balance of audio quality.”
Letshuoer information

Click to expand...

The introduction of this passive radiator called R-sonic has caused discussion. Initially, it was described as a passive radiator but in fact, it is more of a passive filter, which probably helps to eliminate the pressures that accumulate at slightly high volumes. In fact, like on the Hidizs MP145, you can raise the volume enough without feeling excessive pressure in the ear canal. However, I cannot be certain that the result I feel is not just due to the internal structure.

Best shot
The result obtained by Letshuoer is a planar IEM with a slightly warmer tone than the S12 Pro. I think this tone is more pleasant in general and suitable for a wider audience. Your favorite tracks are all enriched with macro and micro details. I don’t notice any problems of any kind except that you need tracks without imperfections; otherwise, you will notice those too. Although the bass is less high, I can confirm that it is felt more clearly and cleanly. The sub-bass is a little light.

Tips Rolling?​

The tips included with the Letshuoer S15 are practically the Nicehck 07 and the Whizzer SS20 (or very similar in design) so excluding cheaper models, I had the Dunu S&S and the Divinus Velvet to test. I am aware that upgrading the tips can have a lot of advantages for a planar IEM like this one.

• The Divinus Velvets, as usual, prove to be universal; every headset you mount them on will give you the perfect seal and improved comfort. In terms of sound, I didn’t notice an exaggerated change.
• The Dunu S&S, on the other hand, proved to be the tips that offer the greatest change—improved soundstage—but also the image seems to benefit. Surprisingly, there was no reduction in low frequencies; it was just slightly less comfortable.

Bass​

Without a doubt superior to the S12 Pro, where perhaps they were slightly suppressed with the treble. However, with very clean and controlled bass, it completely envelops you with high-quality bass and gives a great sensation of depth. The graph shows a roll-off, but they seem like a nice, gentle sub-bass with just the right amount of rumble.


When listening to a bit of deep house or D&B, even if it lacks a bit of extra push, the quality of the bass and its thickness fully satisfy you. If the track requires it, the bass enters the scene in a decisive and auroritary way.

Mids​

The midrange is fabulous, the voices and instruments are definitely in the foreground, and there is a warm note that gives depth to both. Stringed instruments have that warmth that gives them the thickness and reverberation of the strings in the air, as do the voices, which are vivid and silky. All were separated perfectly and accurately. The result is so beautiful that it adds musicality to each track. The bass remains well separated without covering the midrange, giving a very clear result. The tonality of both musical instruments and voices seems decidedly coherent and natural to me.

Treble​

Finally, more refined and tolerable trebles even at high volumes. The S12 Pro seemed borderline to me, and when I turned up the volume, the treble region was very tiring in the long run. Here the highs, as you can also see graphically, are much more contained but the result is excellent; no detail or air is lost, in my opinion. Everything is more balanced and easier to interpret. Excellent amount of macro- and micro-details.

Soundstage and Imaging:​

The Letshuoer has a significantly improved soundstage compared to the previous ones. Sharpness and image have certainly improved, thanks to the new tuning, which allows all ranges to not overlap. The separation is at exceptional levels; all the musical instruments are correctly positioned and never confused. The general result is excellent performance, and its timbre adapts to any musical genre. I think it’s the most versatile IEM currently in my collection.

Comparison:​

vs Letshuoer S12 Pro


Many still appreciate them and at the current price, who can blame them? Most people haven’t heard too much high-pitched sound like me, but actually, at human volumes, there are no problems. Obviously, I prefer the tuning of the new S15 and above all, the soundstage is significantly better. Their design, although very minimal, I liked more.


vs HIFIMAN HE400Se


The Hifiman He400Ses are a miracle for what they cost; they sound decidedly flatter and more natural (typical Hifiman) but the dispersion of the sound they have must also be considered. Certainly, those who buy this model do not intend to be isolated from the outside.


Who win? Surely the Letshuoer S15 is definitely better but it also costs three times as much. The direct comparison is difficult but in my opinion, modern IEMs can easily compete with full-size headphones.


vs Hidizs MP145


The Hidizs MP145 for half the price, remains the queen of the scene when it comes to planar IEMs. I recommend you read the full review to get an idea.


The bass on these has an extremely particular impact, but the S15 beats them in terms of image clarity and perceived detail. Let’s be clear: we are not talking about day and night. They are both must-have models with different tunings and conceptions. Pay attention to the size of the Hidizs because not everyone finds them comfortable.


vs Kefine Klanar


Kefine is a new brand but I must admit that as their first product they have produced a successful planar IEM. The tuning is very warm and smooth so it will appeal to a wide audience. At the asking price it is certainly an option to take into account but if you are looking for something less relaxed you should at least switch to the MP145. If you don’t know them, I still recommend you read the review.

Conclusion:​

Finally, we come to the conclusion with my final thoughts. For my aesthetic taste, they are not the most beautiful on the market, but it is a detail I can ignore, as the most important thing is the sound. The market is increasingly saturated with proposals so standing out from the crowd is increasingly complex.


However, the aesthetic factor is often what triggers the customer’s desire to purchase a product. Here, I realize that not everyone might like it and many give a lot of importance to aesthetics, especially if you pay more than 300 USD.


Letshuoer has raised the level with the S15; its performance is very high, and even with the integrated technology, it is difficult to say whether it works or not.


Personally, I am of the opinion that when a certain sound level is reached, the sound undergoes a sort of change. I think the passive filter works better under a certain sound pressure. In any case, I’m not sure.


From my wallet point of view, a price under 300 USD would be decidedly more attractive and suitable for a wider audience.


Without a doubt, a fantastic set, with a decidedly high price (although it must be admitted that there are far more expensive things) and a tuning suitable for any musical genre.

Where to buy?​

LETSHUOER S15 Third Generation 14.8mm Planar Driver R-Sonic Passive Filtering Module Hifi Wired In Ear Monitor

The S15 is the successor of the popular S12 PRO earphone. An updated version that features a third generation, 14.8mm planar dual chamber driver. To ensure smooth transitions between the octaves, LETSHUOER S15 employs a dual acoustic tube structure with filter crossover scheme. Furthermore, a 6mm passive filtering module outside the planar driver, which uses the in-house developed R-Sonic Dynamic Harmonic Technology, is used for positive filtering of sound energy through proprietary filters.

Non Audio stuff

The earshells of the S15 are made from a combination of 3D printed resin compound with CNC curved aluminum alloy faceplates. They are anatomically shaped and lightweight, offering a stable and very comfortable fit but the nozzle is too short so some of you might need double or triple flange ear-tips that are not included in the package.

Build quality is great but the appearance is rather dull, there is nothing attractive about it, the S15 is boring without the premium feeling to go along with the asking price.

The 1.2m long, 2-pin detachable cable is made from 216-strands of silver-plated monocrystalline copper. It is a modular design with interchangeable, 90⁰ angled plugs. The package includes 2.5mm, 3.5mm and 4.4mm plugs. This is a durable and well made cable with reinforced sheathing and minimal microphonic noise but it is rather thick and a little heavy.

The LETSHUOER S15 comes into a nice cardboard box with a bottom drawer that includes all the accessories. A water-resistant, rounded case made from plastic, two sets of ear-tips in three sizes each and the detachable cable along with the three plugs.



Audio stuff

With 30Ω impedance and 106dB of sensitivity, the S15 is rather easy to drive without needing special amplification. It scales well with some extra power and a competent USB DAC dongle will do the job perfectly fine. For this review I have mainly used the iBasso DC04PRO, Cayin RU-7 and FiiO M11S. As per usual practice, the LETSHUOER S15 was left playing music for about 80 hours before listening evaluation.

The LETSHUOER S15 is not made to impress with ultimate technicalities or some kind of a popular tuning. It is a balanced earphone with a fantastic and a bit laid back sound character that grows on you after a while to become an addition. Don't get fooled and start analyzing frequency response graphs, just close your eyes and immerse in your favorite music only to find out that the LETSHUOER S15 is extremely musical, engaging and natural sounding with special timbre realism. The music that reaches your ears is lifelike, harmonious and very colorful.

The bass is more than enough to offer great satisfaction with all kinds of music, from electronic to classical. Actually, the bass is masterfully tuned, it is mildly emphasized, not too prominent but not too linear either, it is tonally accurate and moreover it doesn't bleed into the mid-range or get muddy. This is a bass that sounds fun and critical at the same time. It is dynamic and impactful with good definition and layering. Tight, fast and controlled, full bodied, weighty and visceral without audible resonances. It might not be the most technical and transparent bass but it has a great sense of realism and power that competitive planar magnetic earphones will have a hard time to match.

The mid-range is present, harmonious and natural with just a little emphasis in the upper mids. There is no point in analyzing whether certain instruments or voices will stand at the front or the back of the mix. What matters the most is that everything is reproduced in a lifelike manner. Notes have plenty of weight and roundness around them, the S15 is resolving and refined with good clarity and definition. Instruments and voices are reproduced with realism, woodwinds sound like woodwinds, brass like brass and violins like violins, you get the point. This is an earphone able to extract all the diversity and the essence of the music making for a very addictive and unforgettable listening experience.

The treble is a great departure from the LETSHUOER S12 PRO with its mildly sharp and bright tuning. The treble on the S15 is toned down a little to make for a smoother, less edgy and more forgiving sound. This doesn't mean that the S15 is muted or short of extension and energy. This is not the most airy and luminous earphone but it is not lacking in either clarity and definition while it is very resolving. Detail retrieval is certainly good but this is not the most analytical and brilliant set of earphones. What really sets the S15 apart from some of the competition is the finesse of the texture as well as the naturalness of the timbre. Higher pitched instruments and voices sound weighty and full bodied without any kind of induced artificiality or metallic harshness.

The soundstage is wide and spacious with very satisfying separation and imaging. Nothing spectacular when it comes to depth layering or holography but still the presentation is grand and realistically proportional with a great sense of the ambience.

Conclusion

The LETSHUOER S15 are excellent sounding earphones with a very musical and engaging sound signature. With their latest earphones and namely their flagship, the Cadenza, and the entry level DZ4, LETSHUOER have proved that they are not afraid to break some eggs and part from the trend. Thankfully enough because together with the S15, they have made three excellent sounding earphones that combine solid technicalities with a great sense of musicality. Something difficult to find these days where most earphones are either trying to impress with stretched technicalities or are tuned using the same target curve that we are all supposed to like.

This is a very mature earphone made for listeners with trained ears who know to appreciate timbre realism and tonal balance more than anything else. The LETSHUOER S15 will make your music sound like real music again and become your daily addiction before you even know it.

The review sample was kindly provided free of charge.
A more comprehensive version of the review with selected comparisons is available in my website.

Hello everyone, I appreciate you stopping by. Today, I'll be sharing my thoughts on the S15 in-ear monitors (IEMs). While there are already numerous reviews and discussions surrounding these IEMs that provide a fair understanding of their performance, I will try to provide my personal impressions, highlighting what I found appealing and areas where I see scope for improvement.

Letshuoer holds a prominent position in the audiophile community, known for releasing a range of IEMs spanning from budget options to high-end flagships, all well-received by us enthusiasts. Together with 7HZ, Letshuoer has held a special fan following for its production of quality planar IEMs. Letshuoer released the S15 as the successor to the highly regarded S12, integrating newer technologies and accompanying it with a noticeable price hike. In this review, we'll deep dive into what this new generation of IEMs has to offer and assess whether they meet expectations.

I would like to thank @LetShuoer Audio and Ivy for arranging a unit for me. It's important to note that my opinions are entirely unbiased, and I haven't been influenced or instructed to overly praise these IEMs. Every mention in this review is a sincere and honest reflection of my experience.


Rating Criteria:

I want to lay out my rating criteria before we start off. For me, the primary criterion for evaluating audio gear is its intrinsic value rather than its price tag. A higher price doesn't always correlate with superior quality, and similarly, a low-priced product can give enough listening pleasure for it to be called outstanding. I consider the build, features, and, most importantly, the impact on the listening experience. The fundamental purpose of audio gear is to enhance the listening experience. So for me, this degree of enhancement in the listening experience is a key determinant in rating a product.

Rating below 4: I really won't be posting reviews of such items unless someone has asked for them.
Rating of 4: The product is good, and some users may find it more satisfactory, but it does come with a few caveats, such as price, fit, etc.
Rating of 4.5: The product is excellent and comes with an easy recommendation, reflecting its high quality and overall positive attributes.
Rating of 5: This product can be deemed groundbreaking, a trendsetter, and an eye-opener and deserves a spot on everyone's list due to its exceptional features and outstanding performance.

Technical Details:




Tech Inside (in simple terms):

According to the official information provided by Letshuoer for these IEMs, they have incorporated several technologies in the development of S15. From my understanding of these implementations, it appears that the primary goal is to provide a comfortable and natural listening experience without causing fatigue.

One notable feature is the implementation of the R-Sonic Passive Filtering Module—a crucial membrane that dynamically adjusts and optimizes the ear canal pressure based on the sound pressure level within the IEMs. This design helps minimize any potential listening fatigue, especially during prolonged use. It sounds like a feedback loop in action.

Additionally, the IEMs feature third-generation planar drivers. While these drivers share a similar size across generations, there have been internal modifications, details of which I'm not able to get my hands on. S15 incorporates a unique design known as a dual acoustic tube structure with a filter crossover scheme. This design ensures the smooth flow of different frequencies to their respective tubes, contributing to a more cohesive and pleasurable listening experience.


Design, build and fit:

When unboxing the iems, the first striking feature you notice is the color scheme and finish of the entire package. The soft blue color, coupled with a matte finish on the case and iems is aesthetically pleasing. So, S15 catches your attention from the first go. The iems are small, lightweight, and quite well built. The combination of the aluminum metal face plate and the soft matte finish on the iem body is quite decent. These iems fit quite nicely and are easy to put on for a very long time without any fatigue.

Additionally, the presence of three vents on the IEMs suggests a design aimed at mitigating pressure buildup, and in my experience, I encountered no issues of pressure buildup during my time with them. I also never encountered any driver flex in these iems, as few have mentioned.

The packaging includes a variety of accessories. The modular cable is well-crafted and offers versatility with interchangeable 2.5, 3.5, and 4.4 adapters. A decent selection of balanced and vocal eartips is also included, although I personally prefer using the Azla SednaFit Light eartips. The wide bore on these eartips, in my opinion, brings out the best sound from the IEMs.

Overall, the unboxing and initial usage experience are highly satisfactory, aligning well with the product's price point. However, the ultimate test lies in the sound quality. We will try to understand the sound profile of these iems in a while.



Sound Analysis:

Right from the get-go, the tuning on these iems is very pleasing. These iems have a warm and balanced signature. The sound is U-shaped, with some bass boost and some emphasis in the upper frequency region, not deviating a lot from a neutral tonality. The timbre is quite good, not shying away from hinting at the typical planar timbre. The sound maintains good coherency. Let's try to understand how different frequencies perform on these iems.

Bass:

Bass is something to talk about on these iems. They have an abundance of bass—punchy and impactful—something that does not seem to be overdone. There is a midbass focus. The subbass, though not very deep and rumbly, shows up when called for, but it's not as prominent. People who like bass on dynamics drivers would not miss a lot with these iems. The quality of the bass is quite commendable for a planar iem. The bass has a natural feel. It does not get bloaty or boomy in the entire low end, maintaining a great balance. The low-end sounds from strings, chello, etc. are very enjoyable.

Compared to bass on something like the EA1000, it is still a few inches behind. The bass on S15 is not as reverbing and natural, but it does not disappoint either.

Mids:

The mids on these iems are clean, thick, and lush, having as much tonal weight as one would need. The vocals are relaxed and hit the right spot. Both male and female vocals shine equally well. Also, thanks to the good technicalities in these iems, the mids get ample space. You can easily distinguish and define the richness and sweetness of sounds coming from instruments such as guitars, violins, etc.

The lower mids have a better body than the upper mids, as the latter has a feel of thinness towards the end of it's spectrum. The upper mids are, however, well controlled, and they do not get sharp or shouty at all. This leads to easy listening most of the time.

I still would not give a full thumbs up to the mids, but then it's tough to point out what exactly is missing. There may be a bit of extra emotional touch, but there are surely very musical and lovely mids there. I also feel the mids could just be a bit forward, but that can be a nitpick. However, on powerful sources, I can see these things do get better, mids have more energy, and they take a front seat. I can most certainly say the mids on these are some of the best ones you can find on the planars.

Treble:

While the bass and mids on these iems are quite well defined, the treble takes a back seat. Treble lacks energy and a sense of airiness but is not far behind either. So, something like cymbal sounds can be felt, but they lose as much shine as one would expect. The presence of air and sparkle in this frequency range is not very pronounced. I am not a treble head, and this treble definition is still fine to me. This is bordering on a dark signature. I enjoy this relaxed signature as it is fatigue-free and fits well with almost every type of music.

When I pair this with the Earmen Angle, which is a neutral to bright source, things certainly get better. A warmer source can make things a bit veiled, and the resolution can take a hit.


Technicalities:

These iems are good at detailing but do not put everything forward. The soundstage on these iems is above average—not the widest, but surely a good width. The depth and height are good enough to give a sense of spaciousness around the head. The imaging and layering are quite good, too. Each instrument gets its due space to shine. However, I do feel resolution could be cleaner, which is somewhat evident on a very busy track. On a less-busy track, things are still quite good.

There is a metallic glare that is present on most of the planars. S15 too has such glare but is less pronounced. With a bit of EQ, things become a lot more natural.


Cable Pairing:

The cable that comes with these iems is quite appropriate. The modularity it offers is truly praiseworthy, catering to quite a lot of sources. I am impressed with the quality and finish of these cables—shiny, sturdy, and visually pleasing. The iems sound as good on this cable as on other cables. I haven't observed a notable improvement in sound quality when using pricier cables; this cable holds its own in delivering a satisfying experience.

Source Pairing:

In terms of driveability, these iems do need a bit of extra juice to shine. Though they are easy to drive, they need powerful sources to show their full potential. They pair well with both the sources I tried, LPGT and Earmen Angel. I do not think it scales too much, but yes, added power does open these iems a lot. Moreover, when paired with a neutral to bright source, such as the Earmen Angel, these iems truly come into their own. The result is an enhanced sense of airiness and openness, elements that contribute significantly to increasing the overall sound quality of these iems. The good thing with these iems is that they do not hiss with Angel, while something like EA1000 and Freya2 do have a background hiss, and they really perform well on Angel, given that it gives it a lot of power.

Comparisons:

With Hidizs MP145 (139 usd):

I am in love with these iems. I am fully biased toward these. They have an extraordinary soundstage, a very vivid out-of-the-head experience.

The bass is on the leaner side. Also, the planar timbre is not quite pronounced on these, but the timbre and tonality on the S15 are definitely better. MP145 is the brighter of the two.

The size of MP145 is massive, so S15 has a much better fit and is lighter of the two.

With Kefine Klanar (90 USD):

In terms of price, these two iems are poles apart, but I do not have any other planar iems to compare the S15 to. Klanar is priced a lot lower than the S15. In terms of fit these iems are quite comfortable. They are light and not quite big.

I love the bass on Klanar, which goes really deep and has enough impact. The bass on both of these iems is quite comparable in terms of weight and impact, though the characters are different. Klanar have thinner mids.

Technically, Klanar does not have the blackest background and cleanest sound, and there is bit of hazy presentation, although this is something one can live with given it's price. Technically, S15 is miles ahead.



Conclusion:

This is the first time I have spent this much time with a planar iem. As far as my understanding of planars goes, they are a hit or miss in terms of timbre. However, with the S15, both timbre and tonality reach great levels. It is one of the good releases from the year 2023. Throughout my time with these iems I never had any complaints, and I enjoyed them as much as I enjoyed my other sets.

But the real question is: Is the price tag justified? I think that's a big question to answer. It's evident that Letshuoer has dedicated significant effort to deliver a comprehensive package with these in-ear monitors. The appealing aesthetics, solid build, generous accessories, and quality cable all underscore the team's commitment to providing a satisfying user experience. While all these elements are justifiable, comparing the S15's price point with other planars and some good non-planar iems reveals a potential disparity. Something like the Hidizs MP145 at 130 USD is a lot more justified when we talk about the price-to-performance ratio. In terms of sound quality, the S15 excels, but the pricing might be perceived as less justified when considering alternatives.

That being said, these iems are one of my favourites from the last year, and I am sure most of the people who have tried them would surely recommend them. They are a lot more than just impressive. Not only are they aesthetically pleasing, but their sound is also beautiful. Who knows, Letshuoer might introduce attractive discounts, making this great experience more accessible to a broader audience. I would rate these iems a 4/5

Letshuoer has provided a sample of the S15 planar IEM to Audio Reviews Downunder Australian tour group to assess and review and I would like to thank them for that.

The S15 is the company’s latest iteration of a planar driver after their success with the S12 and the S12 Pro. The S15 is tuned differently from its earlier cousins with a 6mm Passive filter, dual acoustic tubes and a new acoustic structure. While I don’t pretend to understand the technicalities of the design, (I’ll leave that to others) , I believe the object was to move away from the S12’s V shaped sound profile to a new, more natural organic sound to appeal to a wide range of listeners. We will see if they succeeded.

Firstly, to the IEM and the packaging. This would have to be the most premium packaging I have come across with high quality boxing with a slide out draw that holds three modular connector pins (2.5mm balanced, 3.5mm and 4.4mm balanced) with a smooth cylinder in the same colour to the IEM containing an excellent modular cable and a range of ear tips. Two sets of silicone tips are supplied, described as "Vocal ear tips" and "Balanced ear tips" The cable has an excellent feel and while the ear hooks have a tight bend they anchor solidly to my ears. The S15 has a 3D resin shell with a aluminum faceplate and I find the design quite understated but elegant. The body is light and fits my ears very comfortably and I can wear it for extended periods without discomfort. It has an angled nozzle which also helps the fit.

I auditioned the Letshuoer S15 with my Hiby R3 saber with the 2.5mm balanced output and high gain selected. I was not happy with the supplied tips which had a soft core and were difficult to fit. After trying several brands, I settled on the TRN T tips which emphasis the clean vocals and gave the best soundstage. The IEM is easy to drive and not demanding but it did seem to sing better with a liberal application of volume. On the Hiby I ranged between a volume setting of 40 to 50 depending on the source tracks and how well they were recorded. Older 20th century music quite often needed higher volumes to bring out the best. Supertramp excluded!

The first impression is how full and punchy the S15 is. This is not a V shaped S12. It’s a totally different animal. It’s lush and warm but with great separation and presence. The sound is very natural with little evidence that you are listening to a planar driver. This would have to be one of the best bass performers in the planar category. For quantity, speed, refinement and impact the S15’s bass is first rate.

The track “God willin & the creek don’t rise” by Ray Montaine had a bass drum that sounds like a thunderclap with the S15. Ray’s vocals are forward and sweet and the rest of the band arranged around him in a medium soundstage. Left to right, the soundstage is moderately wide, not extending outside your head. Depth and height are moderate giving an intimate listening environment.

“California Soil” by London Grammar has got great depth and rumble. The percussion is sharp and clear and Hannah’s voice is centered in the soundscape, clear and natural sounding. Putting on some Daft Punk , we have deep rumble, thudding bass drum, a solid floor of bass guitar with clear funk guitars over a well defined male vocal. Very impressive.

'Sundream' by the Australian synth band Rufus Du Sol proves that the Letshuoer S15 is a versatile IEM rendering the synth drums and bass with correct weight and impact while the bell like synth sounds cut thru with crystal clarity. Other tracks prove the S15 can rock out with the best of them.

Conclusion

If you are considering investing north of $300 usd on an IEM you will expect superior sound quality for your money. With excellent bass delivery, forward and warm midrange, with great vocal delivery and detailed non fatiguing highs. The Letshuoer S15 will impress.

Introduction!
Hello friends, I'm ICYGENIUS and today we're going to talk about the absolute amazing $330 planar headphones from Letshuoer!
And they come in a weighty, pleasantly designed medium-sized box, there is the company logo, and the name of this new model S15, and of course there is the high-res audio logo, where would we be without it!

Well, the technical specifications are indicated at the back, and a 14.8 mm planar driver and a 6 mm R-Sonic passive radiator are responsible for the sound, and the sensitivity of the headphones is 106dB and they have a 30ohm impedance, and I’ll say right away that they are not very hard to drive.

Let's take a look at what's included!
And the first thing that greets us here is this envelope, inside which there is a warranty card, a product certificate, and this poster, you can hang it on the wall as an option and look at it and immerse yourself even more in the world of hi-fi when listening to headphones, but humor aside, here at the back there is simply a large instruction manual in 3 languages on how to use and operate the headphones.

And here the headphones themselves are neatly secured, which in my opinion look great, the body here is made of very nice matte plastic and on the front panel there is an insert with an interesting pattern, and next to it there is a 2-pin connector that runs exactly flush with the body, and next to this is where the first acoustic hole is located.

And two more are located on the inside of the earphone where there is the inscription LETSHUOER S15 and the right and left channels are indicated, and the nozzle here is not too elongated but quite wide and has a protrusion due to which the ear pads do not fly off anywhere and cling very tightly.

Well, with the fit and ergonomics, everything is in order here, they fit perfectly in the ears, very tightly and provide excellent sound insulation.
Accessories!
Well, now we smoothly move on to accessories and the first thing we are greeted with is this dense round box made of pleasant soft-touch plastic!

And inside it there is such a new and updated cable, a little similar to the one that went to the Shuoer S12, and I really liked it, it is flexible, weighty, has excellent formed earhooks, and received 2-pin connectors for connecting to headphones and the ability to change the plug to any of three, both standard 3.5jack and balanced 4.4jack and 2.5jack, and they are all angular.

Well, the final touch is this set of excellent ear pads in a convenient organizer!

How do these headphones sound?
Well, I could talk about the sound of these new and, in my opinion, best planars of this year for hours, but for you I tried to present everything as briefly as accurately and clearly as possible because this super neutral and warm presentation makes you fall in love with it literally from the first listen, this that case when I was really hooked on listening to music and just day after day I couldn’t help but pass by and listen to them.
This is what their frequency response graph looks like and they are tuned perfectly, everything is literally the way I like it, an excellent rise in low frequencies and a neat, albeit slightly shifted peak in the upper middle at 2 kHz, which I liked as a solution, and of course, all this is very complementary long and detailed treble, with a small hole for compensation at 12 kHz.

Low Frequencies:
And I’ll say right away that the sub-bass area in these headphones is very dense and massive, it is well accentuated and the sub-bass here has excellent depth and weight and is in no way inferior in its development to top-end hybrids at this price, and texture reproduction is at an excellent level in terms of transparency , that is, the bass does not sound booming and monotonous.
The mid-bass region here is generally excellent, it is even more thoroughly emphasized than the sub-bass, and despite the slight approach to the middle, it is perfectly controlled and does not give any muddy vocal effect as happens in other headphones, and I think that this is precisely because of the planar emitter, based on my experience, if there were a dynamic emitter here it would be more audible.
Well, that very frisky speed with a super emphasized attack and characteristic impulse is, of course, in place here, and the super smooth and neat decays from the letshuoer s12 have not disappeared, but only improved.
Mid Frequencies:
The mid frequencies here are presented exactly the way I like them, neutrally with good additional mass in guitars and instruments, and with some kind of unrealistic natural elaboration of timbres in both instruments and vocals without synthetics, and therefore I immediately liked how the midrange is presented here due to its incredibly pleasant feeling of warmth and almost excellent transparency, which is not in abundance here as in other planars, but exactly as much as is needed so that the area does not sound overly monitory and analytical, but on the contrary, the drive and musicality that many are looking for are preserved here.
What about male or female vocals in these headphones sounds very clean and smooth and understandably without sibilants, and in terms of location it is not very forward, and as for me it is at the absolutely correct distance in order to sound more pleasant and not tire you with its excessive forward importunity.
Well, as for the snare drums and the drum part in general, they are perfectly and correctly emphasized in the mix, just the way I like them, they don’t try to take a lot of attention and are simply presented warmly and neutrally pleasant to the ear with excellent emphasized transients and transition processes.
High Frequencies:
But at high frequencies, in my opinion, there is an absolutely correctly implemented approach to tuning, there is also technicality, which is why we fell in love with those same letshuoer s12, and excellent detail, but I am especially pleased with the even more mature and correct from the point of view of audiophile sound, finally completed, here now there is no excessive brightness and sharpness of the plates and some kind of metallic coloration,and all the percussion and cymbals now sound more accurate and correct and of course pleasant to the ear, this area does not tire at all, and simply allows us to enjoy the music playback, without any resonances and super tough analytics as was the case in s12, so I can now more calmly listen to heavier genres with a bunch of instruments overloaded with distortion, and these headphones easily deliver this area almost as safely as possible, not allowing you to pay attention to any recording problems in the composition you are listening to.
Well, it’s also worth noting the generally excellent bias in micro and macro details, so all the different after-sounds of percussion will be in the palm of your hand and they won’t evaporate anywhere, and very long tails from reverberation will sound as extended and accurate as possible.
Stage and stereo panorama:
The sound stage here turned out to be excellent in width, in my opinion, this is exactly the correct and familiar and familiar construction of the stage, without excessive stretching of the images and their blurring, and at the same time there is a good stereo panorama and its elaboration, and everything in the end sounds very accurately verified and clear by its location.
My conclusion on these headphones:
Letshuoer S15, without any doubt, for me, turned out to be the most pleasantly tuned planar headphones of this year, with a very warm, neat and moderately technical presentation, there are very dense and attacking low frequencies complemented by pleasant mids, and all this is complemented by neat without any harshness and pseudo high-frequency detail and are great for all genres.

Link where you can buy them!
Letshuoer Official Website: https://letshuoer.net/products/lets...ve-filtering-module-hifi-wired-in-ear-monitor
Aliexpress Letshuoer Official Store: https://aliexpress.ru/item/1005006156571806.html
I will be glad if you subscribe to my YouTube channel and watch this full review on LETSHUOER S15!

Lets talk about the Lestshuoer S15 successor, replacement or evolution of the very well accepted S12, s12 Pro, Z12 line of IEM. It come in a medium sized box with a large array of very nice accessories. Let's start with the 3D printed case it is similar to the DZ4 made from hard plastic with a soft feel to it, it should provide adequate protection and storage of the S15. Personally, I would have liked a case they use more often but I can't fault it as it fits everything well. The unboxing presentation was very enjoyable and unique. The cable is very well made, looks good and is modular. Honestly, I couldn't ask for better. Comfort wise the fit will depend on the tips that are included you get two sets with three sizes and wide and normal bore. Isolation and comfort for me were excellent. Build is lightweight due to the 3D printed body. In all honesty these do not look the price, but performance is the draw here. That said I think they look cool, and the color is pretty.





Specifications:

Model: S15 Wired In-Ear Monitor

Sensitivity: 106dB

Frequency Response: 20Hz〜40kHz

Impedance: 30Ω

Chassis Material: 3D printed resin

Cable: 1.2m 216-strands silver-plated monocrystalline copper

Driver: 14.8mm Planar Driver + 6mm Passive Filtering Module



Sound Impressions: The S15 is a smooth and rich almost U-shaped planar IEM.



Bass:

The lower end is more Mid-Bass focused but Sub-Bass has excellent texture and a natural roll-off with a notable rumble but only as a footnote to the details as the majority of the bass is mostly neutral. Bass in general has a fine punch with an above average dexterity, and it is also well controlled with minimal leakage. It present warm and with a fine smooth detail.

Midrange:

The lower Mids are as smooth and rich as honey, such a lavish tone so pleasant with whatever I was listening to. The upper Mids present with good clarity and vocals both male and female are lush and smooth without missing important details. This S15 is far and so much different than its siblings the S12 and S12 pro.

Treble:

The highs will not impress the treble-head, but the sensitive will rejoice with glee. The Treble is relaxed and still presents with minimal sparkle and air, but it just avoids darkness and yet still manages to push out a fair amount of details that sound natural and clear.

Soundstage: is wide, I found it to be precise in imaging and with clear positioning where instruments were, congestion was not heard, and I do thin while not as huge as some others it would work well for gaming and movies on the go.

Afterthoughts:

The S15 is a quintessential example of a smooth and pleasant tuned IEM done right its warm lush tone goes well with all genres of music and compliments Jazz, LoFi and rock amazingly. It should be noted details are not missing just kept natural and not in your face. The separation, and placement are near perfect. Compared to other planar like the much brighter S12, the more balanced and rounded AS-one, and the more V-shaped MP145, the S15 has a unique take on the planar experience.

Introduction

It was not a new brand when LetShuoer launched its IEMS planar S12, but it is true that it has been one of its most famous models. It is also true that the brand itself has been going round and round about the same model, bringing out variants such as the Z12 or the Pro version, until it finally decided to bring out a new planar. And even the process has not been easy, as it has been delayed after the first demonstration units. Officially, the S15 is out this December 2023 and what it brings with it is not just a planar, but the brand has pulled out all the stops with them. The first thing that will catch your eye is the price, which has risen to $329, more than double the price of the S12. So what's in the S15 to justify the price hike? If we look at the exterior, there are many differences. The capsule is high precision 3D printed, the outer face is precision CNC machined aluminium alloy. Yes, it is no longer a full metal capsule. Its design has changed and the surface is as if it were made of some kind of rough resin. Many might think that this new capsule is not worth the high price, compared to the finish of the S12 Pro, for example. So where are the improvements? Well, you have to look inside. The LetShuoer S15s incorporate a third-generation 14.8mm dual-chamber planar transducer. To ensure smooth transitions between octaves, the S15 employs a dual acoustic tube structure with a crossover filter scheme. But one of the most important technologies is the addition of a 6mm passive filter module outside the planar driver. This passive filter module features LetShuoer's new R-Sonic dynamic harmonic technology. This is a positive filtering of sound energy through proprietary filters. This technology is explained in the following link:

https://letshuoer.net/es/blogs/news/letshuoer-r-sonic-dynamic-harmonics

In short LetShuoer R-Sonic PFM uses a membrane that acts as a filter that adjusts the amount of pressure inside the ear canal, allowing the headphone to be adjusted for a more comfortable listening experience, especially during long listening sessions. More details on R-Sonic technology are provided below:

1) R-Sonic is an adjustable module for ear canal pressure tuning.
2) The fundamental operating principle of R-Sonic is the adjustable characteristics of the passive membrane/transducer environment.

While the SPL is louder, the PFM membrane is activated, the pressure is transferred to the earcup chassis and thus the excursion of the active transducer piston movement is reduced. Thus, hearing fatigue is reduced.

Let's see how all this new technology affects the sound of the S15s, as well as other aspects in this review.



Specifications

• Driver Type: Third generation 14.8mm dual chamber planar driver + 6mm passive filter module.
• Frequency Response: 20Hz - 40kHz.
• Sensitivity: 106dB.
• Impedance: 30Ω
• Capsule material: 3D printed resin.
• Outer face material: Anodised aluminium alloy.
• Jack connector: interchangeable 2.5mm/3.5mm/4.4mm 90° angled.
• Capsule Connection Type: 2Pin 0.78mm.
• Cable: 1.2m 216 strands of silver plated monocrystalline copper.

Packaging

The LetShuoer S15 comes in a relatively large grey box. On the main side there is only the brand name on the top left, the model name on the top right and the Hi-Res logo, with the design lines of the outer side of the IEMS on the left side. All in white ink. The back side has the specifications, contact details and the warranty seal. After removing the outer cardboard, only the brand name and the phrase "Sound Alive" appear. The box opens like a lid and the first thing you can see is a closed seal with a sticker just like the external design of the S15 faces. Underneath are the two capsules inside a mould lined with the same cardboard as the rest of the packaging. There is a lower level that opens like a drawer. In it is a round blue-grey box with a rubbery matte finish. It opens with a screw lid. There are also the three 2.5mm/3.5mm/4.4mm connectors angled at 90°. The envelope contains a poster with the logo on the outside. There is a warranty card, 3 pairs of vocal tips and 3 pairs of balanced tips, plus the cable.
Although there is not much variety of tips, the presentation makes for a great unboxing experience and perhaps this feeling justifies the contents.



Construction and Design

The S15 has a big difference in the design of its capsules compared to the S12. It is not metallic, it is larger, the capsules are 3D printed with a bluish-grey resin with a matte look and feel. Only the outer face is made of anodised aluminium alloy and has a relief that is repeated as if it were its seal. You could say it's a letter C with an arrow pointing inwards, all in relief. Going back to the capsule, it is all one piece except for this outer face. It is an integral design that has a slightly more elongated mouthpiece than the S12, it is also larger and thicker. On each one you can read the make, model and channel lettering in white ink. There are two holes on the inside and one on the side, near the 2Pin 0.78mm connection. This connection is flat, the interface is embedded in the capsule. The mouthpieces have a narrower inner diameter (5.8mm) and a 6.2mm crown. They are protected by a dense metal grille. The entire capsule is very rounded and there are no sharp edges.
The cable is the classic LetShuoer two-stranded cable with mixed silver and darker wires inside. The conductor is made of 216 silver-plated monocrystalline copper wires and measures 1.2m. It has three interchangeable 90° angled 2.5mm/3.5mm/4.4mm plugs. The sleeving of these connectors is mixed, near their connection interface is silver metallic, while the elbow is white rubber. All plugs are gold-plated and have tailor-made protective sleeves for protection. The cable exits the connector protected by a small, transparent sleeve. The splitter is a matt metal cylinder. The pin is a translucent plastic ring with a pair of holes in it. The sleeves of the 2Pin 0.78mm connectors are both matt metal cylinders, in the same style as the splitter. There is a dark letter on each of them to specify the channel, there is also a red (R) and a transparent (L) disc, as a base for the two gold-plated pins. There is a velcro strip to tuck the cable away.
Anyone could criticise the new capsule design: it is larger and not metallic. The emphasis on the logo created for the outer face seems to be intended to be an iconic hallmark of the S15 model. And although the S15 is more comfortable than the S12, I like the design of the S12 better - those did have something unique.



Adjustment and Ergonomics

Well, beyond the design, talking about fit and ergonomics, you could clearly say that the S15s have improved over the S12s. Those were smaller, but the nozzles were shorter. Here they are longer, the angle is good and they allow both a shallow and an almost medium, quite occlusive fit. The capsules are light. Their surface is matt and very smooth. The fit is immediate, I didn't have to waste a second to find the right tips, I used my big home-made tips filled with foam and nothing else. Immediate fit, the best possible sound and a great feeling of isolation. There is perhaps a higher degree of rotation than with the S12s, depending on the degree of insertion. But the capsules fit correctly in the pinna to stop the movement. In my opinion, the S15s are an ergonomic improvement which, perhaps, justifies their external design.



Sound

Profile

Let's come to the most important issue of this new model. It is common knowledge that the tuning of planar IEMs has been criticised for the energy of their treble. It is not that it is a peaked high zone, but rather that it maintains a relatively linear extension, spreading the energy over a more extended frequency range. This could cause hearing fatigue for some sensitive ears. Well, LetShuoer has reduced the presence between 2kHz and 10kHz compared to the S12, while almost maintaining the bass and midrange up to that 2khz point. Strictly speaking, and trusting my measurements, there is only a small difference in favour at the 1.5kHz point and to the detriment of the sub-bass end. What does the profile of the S15s look like, then? Well, it keeps that w-shape but now it's in lower case. Everything is more balanced and the result is somewhat darker and warmer. There is not so much reinforcement in the sub-bass, resulting in a more homogeneous sound throughout the frequency range. Perhaps there is some loss of punch, both in the bass and beyond the upper-mids, but the S15s are tuned for hours and hours of enjoyment, with a sound that is quite natural, restrained and free of artifice. This is the result of a more rounded and refined FR, but also with less brightness, hence the darkness and sobriety are more evident.



Bass

First of all, the impact of the passive filter module on the sound is a mystery. As the system specifications state, the R-Sonic PFM device is activated depending on the SPL level, so it releases internal pressure from the IEMS. At what SPL level does it activate? Well, it is not specified. So, in reality, the beneficial outcome of the R-Sonic PFM system cannot be assessed individually. What can be done is to evaluate the low end of the S15s as I have traditionally done so far: with my own ears in the recurring very low-frequency pure tone test. Starting with the latter, one feels that the audible low end does not possess as much energy as its smaller siblings. The response at 20Hz is audible, not very sensory, very subtly coloured and quite good in execution, but not as pure as dynamic drivers of the same price. At 30Hz and above it feels more powerful and punchy, but there is still some colouration replacing a deeper feel. The vibration at 40Hz is more energetic, complete, fuller and already possesses more sensory and physical capability, but the audible side still drags that subtle colouration. This behaviour, translated to real music, explains that certain roughness in the bass, as well as a certain lack of depth and that audible rather than deep feeling in the bass lines. The bass is not heavy, nor does it take up too much volume, but it feels more respectful of the rest of the frequencies, as it is not as invasive. Nor does it feel as predominant as in the S12s. The bass of the S15s is certainly noticeable, but it doesn't come across as a wall of sound. There is undoubtedly a good level of energy, depth and force in their punch, but there is a sense of control, as if there is some limiter - could it be the fault of the passive filter module? I don't know, but it is true that there is no sensation of violence in his hit, even though it is powerful. On the other hand, the rubbery or elastic sensation in the hit is light, but enough to offer a pleasant, deeper and somewhat rounded aspect, together with that subtle roughness on its surface that makes it more attractive and enjoyable. In conjunction with this behaviour, there is also a good degree of speed and low decay. Fortunately for the full development of the low end, the sum of these abilities means that the bass does not feel swamped, bloated or magmatic. The speed of the transitions allows for space between hits, facilitating control, definition and resolving ability down low. Where it shows its technical ability and skill is in the worst conditions. The S15s are capable of reproducing unfiltered bass lines without losing naturalness in performance or distortion even at high volumes. The best thing about it is that it can play such complex bass lines alongside other lines without losing its composure, managing to stratify all the layers, as well as not influencing the upper ranges. Perhaps this is typical for planar IEMS, but I insist that there is that point of control, that release valve that seems to keep the energy at bay so that the bass is executed in the best possible way. Maybe it's a particular feeling, but it's a welcome one, because the result elevates the range.



Mids

I must confess that the S15 didn't impress me enough to leave me with my mouth open on first listen. Perhaps I was expecting a spectacular sound, but that's not the case. On the contrary, it is quite natural, with a certain warmth, soft in the upper range, moderately energetic and very decisive in the lower range. But it is in the mid-range that the natural, neutral feeling is most noticeable. It is true that something that is characterised by being neutral does not seem to stand out on first impression, but rather, with the passage of time and hours of listening, it becomes an acquired taste whose value progresses as the days go by and the more time one spends with them, the harder it is to stop using them. For so are the mids of the S15s, their virtue lies in rounding out the music, in playing it in a more subdued, slightly warmer way, but retaining that gentle neutrality that makes it musical, more analogue, but undoubtedly expressive, descriptive and detailed, to the point of being emotive and beautiful. The S15s possess the ability to magnify the mids, to recreate them in a broad and expansive way, without them even being shown in the foreground. Yes, the male voices are not predominant, but they are very well represented, but also very well wrapped by the whole instrumentation. In this sense, this mix is very well achieved, there is a great respect between music and voices, keeping the distance, balancing the prominence and generating a highly musical, conjunct and euphonic sensation. The result is very pleasant, attractive and highly harmonious. There is no sensation of a wall of sound, although the perception of fullness is almost overwhelming, due to the amount of information it is able to deliver, but without becoming saturated. This is the symptom of the richness of the midrange, of its breadth, but also of its balance, its naturalness and neutrality. If there is one point to criticise, it would be the slight imbalance between the centre and the upper midrange. I would have liked this small step to be smaller, to bring the first half a little closer. It's not the step itself, but the sinking of that first half. Because it's small enough not to elevate the female voices too much, and it's big enough to add clarity and transparency, but without offering a hint of excitement in the midrange. Hence the idea of balance and neutrality in exposure, in the weight of the notes and in their thickness persists. In this way, the distance between male and female voices is not too great, while the mix in the upper range continues to maintain its proportion. The result is a central range that is not particularly prominent (unless tips favouring the midrange are used), but which, without a doubt, has a very ample presential and descriptive fullness.



Treble

Planar IEMS have the advantage that they can subtract energy in their high end, without the sound becoming dull or veiled. I think LetShuoer could have stretched the S15s towards a more clean, crystalline, bright and analytical side, given the capabilities of the driver used. But it has preferred to be conservative in the high end. And due to the intrinsic virtues of this new driver, it has worked out well. The quality of the S15s allows them to be clear and transparent without the need to add energy in the midrange. But it also allows them to be very expressive and with great detail despite lowering the energy in the highs. And that's just it, the virtue is that lowering energy doesn't mitigate or qualify the treble, it's just balancing it out in the mix. The sense of extension and fullness is still there but not as eloquently. Perhaps there is more depression in the air zone, but the treble of the S15s is representative for a moderate, yet rich and sufficiently extended brightness. In that way, the treble is not only smooth, because it maintains a good degree of information and expressiveness. They keep sibilance at bay and are pleasant for long listens or for short, but loud, listens. It is at this point that I realise that the S15s maintain a characterful treble but with a connotation of control taken to a higher level. The S15's treble is not just controlled, smooth, moderate... it's all of that but without losing the virtue of brightness when necessary, yet eliminating the pejorative and penetrating part to maintain musicality and, once again, neutrality.



Soundstage, Separation

In front of a natural, neutral sound, a realistic, well-structured scene is possible. The S15s are spacious, but not three-dimensional, ethereal or holographic. They do not surround the head, but there is a certain enveloping ability, as they are very capable of stratifying and separating music into layers, planes and elements, offering a sense of vibrancy. This ability favours the listening of live music, adding an extra sense of presential realism. The grandeur of the music also benefits from this ability, which, together with the other technical virtues of the driver, allows for a remarkable level of separation and distance between elements. Despite the somewhat dark and warm character of the sound, the S15s are quite transparent. Again, their outstanding level of resolution and definition ensure a very neat, clean, very well delimited sound, which allows a glimpse of a dark background, even space in the separation. This is enough to describe the micro detail, even if it is not faithfully represented in its entirety, perhaps because it is not sufficiently analytical, rather analogue. All in all, the image is expressed in an easy way and the location of the elements appears effortless.
The S15s have many virtues, including the ability to be suitable for long, leisurely listening as well as for more intense, critical listening. In both scenarios, these IEMS will be able to deliver what is asked of them, offering detail, resolution and definition when demanded and smoothness and musicality when listening to music for pure pleasure. This duality is not always present and this adds superior value to this new model.



Comparisons

NiceHCK F1 Filtro Silver

The NiceHCK F1s are perhaps one of the most unknown planar IEMS. However, they are one of my favourite IEMS in terms of sound. They have several characteristics that have favoured them to be so: they have 3 tuning filters, a more analytical sound than the rest of the planars and too short mouthpieces. The latter is clearly a disadvantage, but it favours that the search for suitable tips to improve ergonomics generates a sound somewhat different from what could be expected for its FR. As I say, their mouthpieces are too short and I had to resort to ultra-wide tips instead of my large foam-filled tips. The sound you get with them is not as full, the bass is not as sensory and the midrange, treble and clarity of the sound is enhanced. It loses fullness, but gains detail and resolution. Maybe it is not the most faithful sound to its signature, but it is the one I can get due to its bad ergonomics and the union with the tips suitable to my morphology. In no case the sound is bad, on the contrary, it is very good because it is different. The filter used for the comparison has been the Silver, which provides a more balanced sound.
In terms of construction, the NiceHCK F1 is a medium bore and overly thick cylinder. They are made of aluminium alloy using 5-axis CNC machining. The outer face has a micro-stepped slope to a thick C-shaped carbon fibre flat. The nozzles are short and their angle is not the best of all, the fit obtained is only superficial. With an ultra-wide silicone tip, clarity and a more technical sound is favoured and this is what I notice even though I have one of the most relaxed FRs at that time in high-mids and treble. Now, the S15's are very similar in their FR. The low end seems to be a carbon copy and from 1kHz onwards the differences are small. It is true that the S15s are more rounded in their curve and that gives them a more distinguishable refinement.
I have used the same ultra-wide tips on both models to equalise the listening conditions as much as possible. Sensitivity in both is very even. Overall, the S15s are slightly darker and drier than the F1s, subtly more muted. In the low end, the dryness is felt, offering a tighter, smoother bass. The F1s have a rougher, slightly more textured bass, but are lighter, take up less volume and have less weight. The S15s feel denser and wider, with more energy and fullness, which gives them a greater sense of depth, but they also have more presence and impact within the sound.
There is more light and clarity in the midrange of the F1s, their sound is brighter and contrasts with the greater darkness of the S15s. There is more density in the midrange of the S15s and a sense of greater openness in the F1s. The sound is warmer in the S15s, with a perception of greater fullness and intensity in many respects. The F1s are lighter, their notes have less weight and are thinner. The density of the S15s gives them a more pronounced lushness, although the F1s' lightness gives them more freedom and a little more openness. If you try to match the wall-of-sound feel of the S15s with the F1s, the tendency is to turn up the volume, but the result is undesirable, as the sound becomes less pleasant and gentle, losing the more appropriate control that the S15s do have. Thus, the male voices on the S15s are more physical, fuller-bodied and have a juicier, richer corpulence. The base of these male voices place the S15 among my favourite IEMS in this regard. A similar thing happens with the female vocals and also with the instrumentation. The sense of presence and closeness, as well as its physicality is higher on the S15. It is warmer and fuller, also darker, but its density gives it a very high sense of weight and immersion, which makes the listener become more integrated in the sound.
In the top end the F1s are thinner and brighter, with a little more energy, though they are also more penetrating and not as restrained, softened and controlled as the S15s.
It's true that the thinner notes offer a little more vividness to the micro detail and a slightly more ethereal feel to the ambience, giving a sense of greater separation. The S15's denser and somewhat darker sound is a little more complex and doesn't seem as analytical as the F1. However, it is more refined and pleasant. The F1s can sound more strident, even less natural. Whereas the timbre of the S15s is more organic, warm and analogue. The F1s can offer a more open feel, while the S15s are wider and deeper.
In short, the F1s are finer, cooler and more analytical, have more light, clarity and appear more dispersed and ethereal. They offer good micro detail, but their timbre and note finish is somewhat more artificial, rougher, even harsher. The S15s are denser, darker, warmer, but offer more closeness in both bass and midrange, offering a higher level of lushness and richness. Their sound is fuller, with a heavier, more full-bodied base. But it is also refined at the edges, never harsh and more controlled even in the worst situations. The result is a more balanced, homogeneous, dense, thicker, complete and very musical sound. A step further in musical refinement.



Conclusion

It seems that LetShuoer has given a lot of thought to the release of its evolution of the famous IEMS planar S12. It could have followed the same path and created a more refined planar, following a continuist line. But it has not been like that, the S15 is a different model in many aspects, from its external design, with its capsules printed with 3D resin that gives them a less refined aspect, due to its matte finish and its colour. Ergonomics have been improved and weight has been reduced. In the end, these are aspects to be taken into account in favour of obtaining a better sound and pleasurable result. And it seems that pleasure has been the keynote to follow. The S15s have been softened in the midrange and the overall treble energy has been reduced, for a more balanced sound, with less noticeable sub-bass and more homogeneity in all ranges. The sound is now warm, even darker. A little more light can be obtained depending on the tips used, but it is clear that the treble is softer and more controlled, for a longer and more lasting enjoyment. The sound is richer and more lush, micro detail exists if you look for it, though it is not in the foreground. The S15s offer more than meets the eye at first glance, and that denotes a potential quality that increases with each passing hour.
On the other hand, to achieve these improvements, it is worth mentioning the effort of the brand, adding a new technology inside the IEMS. The S15s combine a new third-generation 14.8mm dual-chamber planar driver with a 6mm passive filter module. This module features LetShuoer's new R-Sonic dynamic harmonic technology. Complex technology for a step up in sound quality in a very tight price range. It's noticeable that when one reaches a point of excellence, every bit of quality one wants to gain costs a lot more and I think LetShuoer has done their part to achieve this.



Sources Used During the Analysis

• Aune X8 XVIII Magic DAC + EarMen ST-Amp.
• Aune M1p.
• Aune Yuki.
• Burson Audio Playmate II.
• Hidizs S9 Pro Plus Martha.

Purchase Link



You can read the full review in Spanish here

LETSHUOER S15

Disclaimer

The S15 is my second IEM from Letshuoer, I got it for free with expectation of written impressions or review. All impressions are my own subjective thoughts, after having used T4 for some weeks.
This is also a very subjective hobby where everything from experience, anatomy or age will affect what we hear. Also keep in mind that it is easy to use bold words when talking about differences, while it may be perceived as a small change for you. While I can perceive something as natural sounding, I do believe we can never get a perfect performance similar to what is achieved live.

Ranking System:
1 Very bad or unlistenable
2 Listenable but not good
3 Average
4 Very good
5 Exceptional or having a special sauce



About me and my gear used for the review

My audio preference is neutral with increased low end, mids can be forward but not too much. I can also handle some treble spikes if it is not excessive. I am a believer in having different tuned IEMs for different genres or moods instead of chasing the single perfect one.
Main music genres I listen to are Metal, Electronica, Jazz, Indy rock/metal, R&B, Pop. I am a music lover, and can also listen to almost all the genres out there. I have been into music gear since the mid 90s, gifted some big speakers at an early age. Then moved more and more into headphones with the Koss Porta Pro and a Sony Discman and Minidisc.

I have also tried playing many instruments over the years from piano to sax and have a feel for what's a natural tone, but not the biggest patience in learning to play. My wife has also played many instruments from string to wind instruments and also piano.

My current standard in Headphones is ZMF Verite Open and Beyerdynamic T1 G2.

My current favorites in IEMs are AüR Audio Neon Pro, Sound Rhyme DTE900 and 634ears Miroak-II. The NEON PRO has 10 BAs, and has a near perfect tonality for me on the brighter side. DTE900 is a tribrid with 1+4+4 config, tuned W shape being energetic and lush. Miroak-II is my favorite single DD, it has a warm and bassy sound that is also very natural sounding.

Gear used in the main rig is Topping E70 DAC together with the Topping A90 Discrete headphone Amp. I also have a Schiit Lokuis I can swap in if I want to do a little analogue EQ.
Portable gear used during the review is HIBY R6 Pro 2, Colorfly CMA M1P, Penon Tail, FIIO BTR7.
I have a good range of cables from Clan Audio, Penon, NiceHCK, XINHS, DUNU, Effect Audio and Gladiator Cables.



So what is the LETSHUOER S15

Letshuoer is a IEM brand that was founded in 2016 in China, they have had many well received releases.
This is their third planar IEM, their previous models have been S12 and S12 PRO. All of them utilize a 14.8mm planar driver, the S15 also has a 6mm R-Sonic Passive Filtering Module. There was some controversy at first since the early leaked posts called it a passive radiator, but the implementation has more to do with having more control of the ear pressure and air flow.

https://letshuoer.net/blogs/news/letshuoer-r-sonic-dynamic-harmonics

The quality of the shell is excellent and has a very nice texture to it, feels in a way more premium than most IEMs.
I also like the color very much, but I also understand it will not be to everyone's liking. The only thing I dislike is the faceplate, it looks cheap compared to the rest. As for ergonomics they are perfect for me, few brands have such a nice build and nozzle. They melt more or less away and don't stick that far out from the ears, the nozzle also has average size and good length without probing your brain.

As always the packaging is excellent, it feels like a more premium unboxing than most ChiFi IEMs. Accessories are also good, you get two sets of tips one for vocal and the other ones for balanced sound.
The provided modular cable looks and feels nice, and also has a secure connection on the modular part. My only gripe is that the ear hooks are too aggressive, making it less secure for me.

https://letshuoer.net/products/lets...ve-filtering-module-hifi-wired-in-ear-monitor












Timbre

First off, what is Timbre?
From the Wikipedia:
The Acoustical Society of America (ASA) Acoustical Terminology definition 12.09 of timbre describes it as "that attribute of auditory sensation which enables a listener to judge that two nonidentical sounds, similarly presented and having the same loudness and pitch, are dissimilar", adding, "Timbre depends primarily upon the frequency spectrum, although it also depends upon the sound pressure and the temporal characteristics of the sound"

First minutes of trying a new set of gear, what I always listen to is how natural and musical it sounds. Much of this goes down to how I perceive the Timbre.

First session with S15 reminded me more of a dynamic driver than planar. I have tried a few planars but was never sold by the sound. Usually they were metallic and bright, I would also call them lifeless.

S15 has a richer and smoother sound, also a forgiving sound that is not tiresome. But can also be fast sounding and resolving, a very musical tuning to my ears.

Going to use the ranges here in review:




Details and soundstage

I dare say it's at the same level of resolution as some of the more resolving 1 DD IEMs, but due to the more forgiving upper range it also has no fake resolution. The dynamic range while good is not the best, and here dynamic drivers can be better.
Soundstage is average, I don't feel it sounds closed in and not that large. As for layering and imaging, it's okay but also here nothing spectacular.

Bass

Best planar bass I have tried, it has both a good slam and extension. But lacks a little on the texture, a little lifeless coming from great DDs for bass. But the S15 is also better than some dynamic drivers.
Sub bass extends low and can give you some good rumble, it lacks a little in the lowest sub bass pressure. Mid bass is much better and can give some really good slam, I was quite surprised by the low end as it's better than what I thought planar IEMs could do.

Mids

Midrange has nice tonality, it has some warmth but is also reserved and relaxed. With this I mean that it has good weight to vocals like males or cello playing, and on females it sounds clean but also not neutral and sterile. There is never any sibilance or shoutyness, this was my big downside on the earlier planars.

Treble

I find S15 airy and resolving in the highest range, it has great extension without being bright or sounding overly pushed to get fake air. As for the lower part of the treble, it sounds smooth and relaxed. Not dull by any means, just a forgiving and musical treble presentation.



Synergies

A small part about what gear I have been enjoying the most with the S15.

Most of my listening has been done with HIBY R6 Pro 2 and Topping E70/A90 Discrete, my favorite pairing being A90 Discrete. I also just got the Colorfly CDA M1P, it has a nice velvet like AKM sound and adds some organic elements to the S15.

Tips have been weird, I started with Spinfit CP100 and loved them. Then after a while I found them to not get the best staging capability of S15, changed to Divinus Velvet and it sounded much better. Another good pairing has been the Tangzu Sancai, just a balanced sounding tip with nice comfort.

Cables I am very neutral on in beliefs, I have tried both expensive cables from Effect Audio and cheap brands like XINHS and NiceHCK. I don't really find it to improve or change with cables, so my pairing has mostly been with a 16 core comfortable copper cable from NiceHCK.





Music

Just some music I have used while doing the comparison against my other IEMs and also against S12 PRO. I have also listened to a lot more during the evaluation progress, but this should give something for you to check out also.











Also check out the British and Dutch compilations, excellent trance releases.



























Comparison to the little brother S12 PRO

The S12 is one of the first planar IEMs I tried, I liked the technical performance and comfortable shell. But this is where it stopped with the praise, I never liked the timbre of the S12. It sounded dry, metallic, sharp and unnatural. The S12 Pro improved it slightly but it was still not to my preference, this is also why S15 impressed at once when I got them.

The sound had a closer resemblance to dynamic drivers in the bass, touch of an organic element. The driver is still detailed and fast with short decay, in the low end. Where it changes is that the bass seems to have better texture and a more satisfying impactful low end.

Midrange has a little extra warmth and realistic midrange, the metallic sound is totally gone on S15. Vocals and clean and detailed, just lack some presence when compared to S12 PRO.
So midrange is about the same in resolution but sounds better on S15, due to the upper midrange being more forward the S12 Pro can have more presence going on without being more resolving.

High range is good on both, it's actually very similar. Has good presence of air in both, sound slightly more forced in S12 PRO. The S15 is maybe slightly more relaxed than the S12 in the high range.

Soundstage is okay on both, but it is not their strong side either. I find S12 Pro smaller than S15, separation and imaging is about the same. They both lack a little in the separation compared to good DD or BA sets.

The spider chart is slightly exaggerated on some points to show differences.





Conclusion

First planar that I want to keep in my collection, it's still planar technology and will lack the dynamic driver presentation. But this is much closer to a dynamic driver and sounds very natural. The S15 has refined the planar sound, and in my opinion deserved the higher price tag above the S12 Pro. Many of us have no problem buying a good expensive single dynamic driver IEM, so why can't we do the same with planar also.

Final ranking from me is a solid 4 of 5, that I find to be very good specially as a planar IEM.

LETSHUOER S15 – 14.8mm planar driver IEM​

LETSHUOER S15 – 14.8mm planar driver IEM
INSTAGRAM: LINK

Prelude:
I usually start my reviews with a short introduction, and this time will be no different. LETSHUOER is a company known for many innovative projects, including planar IEM headphones called s12 or their improved version s12pro. These are interesting products because they started the famous war of planar in-ear headphones and for a long time they held the leading position, or at least took a well-deserved place on the podium. Thus, the competition was developing strongly, outdoing each other in newer and newer projects. LETSHUOER looked closely at the competition and listened to what users thought. Finally, he decided to release another edition of his headphones based on a planar transducer, and that’s how the S15 model came to us. Together with new technologies in the form of an original sound pressure reduction system, an advanced acoustic crossover and a new version of the planar transducer, we were greeted by an increase in price to USD 329. So let’s see if such a price increase is justified.

Unboxing and ergonomics:
The new S15 headphones come to us in a neat cardboard packaging, the quality of the prints is very good, and the retractable lower part with accessories adds a sense of aesthetics. The headphones themselves are made of medical resin in a similar shape to the DZ4, so the build quality is impeccable and the metal front panel looks great. Overall, when it comes to build quality, it is undoubtedly premium, and the headphones are very comfortable. We also have documentation at our disposal, a blue case identical to the one in the DZ4 set, but in a color matching the headphones, it is a plastic screw-on can. The next element is a cable similar to the one from the s12pro, but slightly more flexible and with a set of three 4.4″ angle plugs; 3.5, 2.5 mm with a classic 0.78 mm plug. That’s it, it’s a sufficient set without unnecessary gadgets. I ran out of foams from the s12pro set, but apparently the manufacturer decided that the tuning was for a different type of tips. That’s why the set includes two types of tips: vocal and balanced. Overall, I really like the set and I really like the new LETSHUOER product philosophy.

Sound:
Test material:
Tidal Master, and your own files.
I used EarMen colibri and Angel as a reference device.




Okay, I’ve already briefly discussed what you can see with your eyes, it’s time to move on to the most interesting issue, because everyone is curious whether the S15 really sound so good to justify such a large price increase? For those who are impatient, I can say right now that these are the best planar IEMS on the market, and the competition does not even come close to the level of the s15.

Bass: There is no question of boredom, even on such a neutral and reference DAC/AMP as the EarMen colibri, the low tones were delightfully strong and hit the point strongly. The depth of the bass turned out to be amazing, which could be felt in electronic music and pop arrangements. The low tones were not overwhelming, but instead showed an excellent musical foundation. You could feel and hear all the benefits of the planar transducer. Additionally, the sound pressure reduction system effectively eliminated the feeling of fatigue and provided a smooth and consistent sound without loss of low frequencies. It reminded me a bit of the excellent pressure reduction system I encountered in the NXears sonata headphones. I didn’t feel overwhelmed or undersaturated in the bass range, as it sounded incredibly linear throughout its entire range. I really liked this. I have always liked planar drivers for their incredible technical abilities, but this was usually at the expense of the natural sound, just as armature drivers lacked that delicate warmth.

Midrange: Fortunately, in the s15 model, LETSHUOER took care not only of beautiful vocals and midrange, but also of a bit of non-obtrusive warmth, which effectively eliminates all the shortcomings of the planar transducer. The midrange, like the bass, sounds linear and clean, allowing you to literally enjoy the excellent vocal or instrumental layers. At the same time, the sound stage is the size of a listening room, the S15s sound wide and with very good depth, but they are far from artificially inflated sound, which is a good thing. The technical aspect is not overly demanding, instead the focus is mainly on musicality and the pleasure of listening to music. Together with a very even band, this gives excellent results:


Treble: The upper bands turned out to be brightened, but fit perfectly into the overall tuning of the s15. The number of instruments and separation are at the highest level. The high tones are neither harsh nor unpleasant. The higher diameter allows the instruments to build a realistic and pleasant experience. They may not be overly stretched, but thanks to their linearity and even presentation they maintain a coherent image. This can be especially noticeable when listening to instrumental music and music based on strings. The brightness and natural warmth in the presentation allow you to relax during long listening sessions. I mentioned at the beginning that in my opinion S15 are currently the best planar headphones available on the IEM market. So let’s move on to justifying this position

Comparisons:

LETSHUOER S15 (329USD) VS TIN P1 (169USD)
LETSHUOER S15 These are warmer and much more balanced headphones. Tin P1 were something of a pioneer when it comes to planar IEMs. However, they were very difficult to drive and suffered from a lot of treble. At the same time, the P1 provided an almost perfectly flat sound. S15 takes full advantage of the potential of planar technology. They offer much greater resolution, wider depth and much more resolution and maturity in sound. The S15 are less bright, smoother and much easier to control.

LETSHUOER S15 (329USD) VS TIN P1MAX (99USD)
Tin P1MAX is a great example of how well-implemented evolution can contribute to overall evolution. Strong sub-bass, excellent entertaining sound and a large amount of details made me unable to resist these headphones for a long time. However, the S15 sound more mature, much more scenic and, above all, equally charming with a beautiful midrange.


LETSHUOER S15 (329USD) VS LETSHUOER S12PRO (139USD)
S12Pro are great headphones, but their tuning was quite focused on the V plan. S15 are much more even and definitely more resolving. So I completely understand the price increase. With the higher price we get a significant improvement in performance, resolution and diameter. Increasing the balance of the sound resulted in excellent results. Of course, if someone prefers more bass, they may like the s12pro a bit more, but the s15 provide an amazing experience never seen before in the world of planar IEMs.

LETSHUOER S15 (329USD) VS KINERA CELEST PHHOENIXCALL (139USD)
LETSHUOER S15 are balanced and very even headphones, with strong bass, a lot of air and an excellent midrange. KINERA CELEST PHHOENIXCALL These are slightly sharper, more aggressive headphones. At the same time, I love both tunings and it all depends on our individual preferences.

Summary:
It’s hard to say anything bad about the S15’s design, and when it comes to sound, it’s consistent and coherent. The even tuning and incredible resolution provided by the planar driver are literally felt at every step. The stage has considerable depth and correct width, and the accessories are coherent and complete. At first I was surprised by the price of $329, but now I completely understand it. The tuning and quality of the S15 fully justify this, putting the S15 in the position of the undisputed leader. The S15 will work well in any genre of music and is not difficult to drive, but it benefits significantly from stronger sources. In fact, it’s hard for me to find any weak area of this project. Only fans of ultra-natural tuning may be surprised because the S15 focuses on entertainment and musical tuning with a bit of warmth, I personally like it very much, but you should remember it. Well done LETSHUOER for creating an amazing project that once again amazed me with its quality and functionality.

DISCLAIMER

I would like to thank Letshuoer for providing the S15.
It can be gotten here: https://letshuoer.net/products/lets...ve-filtering-module-hifi-wired-in-ear-monitor (no affiliate links).




SPECIFICATIONS

• Driver configuration: 14.8 mm planar driver + 6 mm R-Sonic passive filtering module
• Impedance: 30 Ω
• Frequency response: 20 Hz - 40 kHz
• Sensitivity: 106
• Cable: 2-pin, 0.78 mm; silver-plated monocrystalline copper; 2.5 mm, 3.5 mm and 4.4 mm modular termination
• Tested at $329 USD

ACCESSORIES

Other than the IEM, these are included:
- 3 pairs of wide-bore "vocal" silicone eartips (S/M/L)
- 3 pairs of narrow-bore "balanced" silicone eartips (S/M/L)
- Cable
- Modular plugs for 2.5 mm, 3.5 mm and 4.4 mm termination
- Hard case

The accessories are quite decent for a midFI pair of IEMs, perhaps other than the lack of foam tips.




2 variants of silicone tips are included. The wide-bore "vocal" ones boost treble and air, and improve soundstaging, whereas the narrow-bore "balanced" ones increase bass but compress soundstage somewhat.




Letshuoer has included a silver-plated monocrystalline copper cable. This is well-braided and tangle-free, with minimal microphonics. I appreciate the presence of a chin cinch, and the selling-point is its distal modular terminals that allow users to pair the S15 with 2.5 mm, 3.5 mm and 4.4 mm sources.




Lastly, we have a round screw-on hard case, which is build like a tank. The innards are spacious and lined with a soft material to cushion the contents.



The rest of this review was done with the stock cable and stock wide-bore silicone tips. No aftermarket accessories were used, so as not to add any confounders to the sound.


BUILD/COMFORT



HeyGears has utilized 3D-printed resin for the housings, with an anodized aluminum faceplate. The housings sport a greyish hue, but admittedly, look a bit childish. Nevertheless, the build is solid and light.




With no awkward protrusions on the inner aspects, the S15 is well-fitting for longer listening sessions. 2-pin IEMs are always my preferred connector-type, as I've encountered my fair share of MMCX failures with cable swapping.




Despite being vented, isolation is actually above average. Sadly, I encountered driver flex on my pair, but this is partially dependent on ear anatomy and types of eartips used.


INTERNALS

The S15 is actually not a pure planar IEM. It houses a 14.8 mm dual chamber planar driver, but also has a passive filtering module, which Letshuoer terms the "R-Sonic Dynamic Harmonic Technology." Basically, instead of a traditional passive radiator, this operates as something analogous to a reverse concept passive radiator, which adjusts ear pressure at different volumes.

For folks interested in the technical jargon, check out Letshuoer's post about it here: https://letshuoer.net/blogs/news/letshuoer-r-sonic-dynamic-harmonics

The planar driver and passive filtering module are aligned via a dual acoustic tube structure, with crossovers.


DRIVABILITY

I tested the S15 with the following sources:
- Apple dongle
- Cayin RU7
- Fiio K11 DAC/amp
- Fiio KA13 dongle
- Hiby R3 Pro Saber 2022 DAP
- Khadas Tone Board -> Schiit Asgard 3 amp
- Questyle M15 DAC/AMP dongle
- Sony Walkman NW A-55 DAP (Walkman One WM1Z Plus v2 Mod)
- Sony Walkman NW A-55 DAP (Walkman One Neutral Mod)
- Sony Walkman NW WM1A DAP (Walkman One WM1Z Plus v2 Mod)
- Smartphone

This IEM is relatively easy to drive, and robust amplification is not 100% essential. It will however scale in dynamics with clean amplification.


SOUND & TECHNICALITIES

Graph of the S15 via IEC711 coupler. 8 kHz is a coupler peak.

Tonally, the S15 boasts of a pleasant and warm U-shaped signature.

It is mid-bass focused, with quantity just a tinge more than neutral. The sub-bass is not the most extended, with a noticeable roll-off, resulting in no big rumble heard. The S15 makes it up in quality of the bass, with solid texturing noted, with a punchy, nimble and clean bass without any mid-bass bleed.

The lower mids are not too depressed, and this region is thick and lush, with an enveloping syrupy tone heard. The upper mids are sedate, with just a 5 dB ear gain, resulting in no shoutiness. The midrange can be described as euphonic as such.

The S15 is a set for the treble-sensitive, there is no sibilance. Indeed, this region is very smooth and fatigue-free. It is a double-edged sword though, as there is a lack of air and sparkle, so trebleheads might want more pizazz. However, resolution is still quite commendable for a signature bordering on the dark side, and the S15 keeps micro-details in check, but does not need to use the hackneyed CHIFI cheat-code of overly boosting this region for "fake clarity".

Continuing on with technicalities, the S15 has above average soundstage, and layering and imaging are a highlight - instruments are easily pinpointed on a dark background. Instrument separation is solid, with music not sounding congested in the least. As detailed above (no pun intended), micro-details are respectably portrayed, though edge definition of notes is somewhat blunted.

Generally, most planar IEMs flop at timbre - possibly a consequence of the fast transients and rapid decay of planar drivers, especially at the bass. Admirably, the S15 has the most natural timbral accuracy I've heard in my journey of around 15 planar IEMs, and the bass has decent decay, sounding close to a DD bass rather than a typical truncated planar-type bass.

The keyword to describe the S15 would be "effortless".


COMPARISONS

Comparisons were made with other planar IEMs. Pure BA, pure DDs and hybrids were left out of the comparisons as the different driver types have their pros and cons.




Letshuoer S12 Pro

The older brother S12 Pro is a more aggressive and bright V-shaped planar, with greater treble quantity and air. The midrange is more recessed, and the S12 Pro's bass isn't as tight too. For the treble sensitive, the S12 Pro's upper midrange/treble is definitely more fatiguing and sibilant.

Soundstage and imaging is better on the S15, though the S12 Pro is more defined in edge definition, and is more "in-your-face" with the music.

The S12 Pro suffers from a marked metallic timbre, whereas the S15 is exponentially more natural sounding. Note weight is thinner on the S12 Pro.


Sivga Nightingale

The Nightingale is a mid-centric planar, with way worse bass roll-off than the S15. The midrange is more forwards on the Nightingale, with greater treble quantity. The Nightingale isn't as all-rounded due to the bass roll-off, and it arguably only shines for certain genres like acoustic and vocal-focused ones, but falls flat in bassier tracks.

Note weight is much thinner on the Nightingale, and it suffers from a bad planar timbre, compared to the more organic S15. The Nightingale is also harder to drive.

In technicalities, the Nightingale has a smaller soundstage and worse imaging/instrument separation, though it has more clarity and micro-detailing, partially as a function of its brighter and thinner tuning.


Hidizs MP145

The MP145 has 3 tuning nozzles and is more versatile as such. Across all tuning nozzles, the MP145 is brighter, with more sibilance. There is more obvious mid-bass bleed on the MP145, and it isn't as textured here.

The MP145 has a tinge less natural timbre, with a thinner note weight. Technically, the MP145 has a more expansive soundstage, with better instrument separation/layering.

The MP145 also suffers from driver flex, and its shells are heavier and larger, so ergonomics are a bit less proficient.


CONCLUSIONS



The S15 is a smooth and lush-sounding planar, bringing to the cut-throat planar fray, a warm and agreeable U-shaped tone, with not a shred of fatigue or sibilance. Our treble-sensitive brethren will be very at home with the tuning, with timbre a highlight amongst the planar competitors.

Despite the warmer (and borderline darkish tuning), resolution is respectable, with imaging and layering done very well. Additionally, the S15 is easily driven, with decent accessories and comfort.

The creamy tuning does come at a cost of treble air and sparkle, so it won't be the cup of tea for trebleheads or analytical-heads. Bassheads might also find the quantity and sub-bass roll-off wanting, though the S15 cedes outright quantity for good quality bass.

In terms of externals and aesthetics, the resin shells look more like a Fisher Price toy than a sophisticated IEM, but the ergonomics are thankfully well-designed, other than some driver flex.

As per diminishing returns in this hobby, the S15's price lies on the steeper side, especially moving from cheaper planars like the MP145 and S12 Pro to this $300ish range. But that is the nature of this beast, sometimes chasing that last 10 - 20% of acoustic refinement will only yield incremental improvement, but at the expense of less value-proposition.

To sum it up, the S15 is well-suited for long chill sessions, yet without much compromise in technical tangibles like imaging, instrument separation and soundstage. Timbre is arguably the best I've heard in a planar IEM. Its warm tonal balance is very affable and enveloping - think of a musical, smooth and addictive syrupy tone, without veering too much to a veiled mushy profile - something that is quite hard to balance.

TLDR version on YouTube: TDLR - Letshuoer S15

The Letshuoer S15 have been sent to me directly by Letshuoer in exchange for the publication of my opinions in this review. They have made no requests or comments and I will do my usual best to be as unbiased as possible.

The official page for the S15 can be found here: https://letshuoer.net/products/lets...ve-filtering-module-hifi-wired-in-ear-monitor

As always, this is a non affiliate link.

To avoid being repetetive in my reviews, you can find all the info about how I create the reviews, equipment used, how I receive the products and how to interpret my reviews by visiting: About my reviews



Intro…

The S15 is the latest release from the company who made one of my favourite planar IEMs, the S12. The S12 were the set I would reach for when I just wanted to listen to music and reset from reviewing things, they got a lot of ear time and they are still in the 10 sets that I most use when I am not reviewing something specific.

Therefore, when I was offered the chance to try out the new planar option, the S15, which features the same size 14.8mm planar driver but now in its third generation, along with a new passive radiator filter, I was excited to give them a listen.

Letshuoer already released a set with a passive radiator not too long ago, the DZ4, and I mentioned the fact that the way they had implemented it was not really what I would call a passive radiator. This did give them a bit of a unique sound that reminded me of a slight tube flavour. Whether it was due to the strange implementation of the PR or not, it was still something that I found very enjoyable for a lot of acoustic music.

When the rumours of the S15 started to appear, there was mention of a passive radiator being used in this set together with the planar driver, something that seemed even stranger than the set up in the DZ4.

However, when the info finally emerged, the S15 are not spec’d as having a passive radiator, rather a “6mm R-Sonic Passive Filtering model”. In this case there seems to have been a lot more thought put into the set up, using acoustic tubes with a filter crossover, meaning that it is not just a driver without a coil put into a shell.

There is a whole page on the Letshuoer site about the “R-Sonic” system, explaining how it works and that it is not PR but a PFM. I am not going to go through it all here as you can just visit the page ([here](https://letshuoer.net/blogs/news/letshuoer-r-sonic-dynamic-harmonics)) if you would like to read it in detail, but in short they say that is is an adjustable module for tuning ear pressure, kicking in when the SPL is higher.

I don’t know exactly at what SPL this is supposed to activate but I am someone who listens at low volumes, so I thought maybe I would be missing out on the fun. However, I have spent some time comparing it at low volumes and higher volumes and personally cannot tell a difference in sound, other than it being louder which can subconsciously lead to thinking that the sound is automatically better.

So, let’s talk about the S15 as a whole and how it performs to my ears.



Presentation…

The S15 is not a cheap set of IEMs, selling at $329 on the Letshuoer site. Of course there are obviously many models out there that are much more expensive but it is still on the higher end of the range of many planars we have available. I have to say that I personally feel that the presentation is on a level that is expected at this price.

A simple grey sleeve that shows the make and model on the front, with minimal specs on the back, slides away to reveal a simple flip top box of the same colour, with just Letshuoer “Sound Alive” on the top in very small text.

Flipping open the box, which is held closed by magnets, reveals something that resembles a small valet box with a drawer (for lack of a better comparison). The top layer is a grey card envelope that contains the warranty card and a poster that has art on one side and the user manual printed on the back. I am not one for posters but I like the originality of presenting the user manual this way.

After removing the envelope we find the IEMs sitting in next layer in usual hard foam cutouts but in this case, they have been covered with matching grey card which makes it look a little more premium.

Below this there is a drawer that pulls out from the front and contains the accessories. The accessories are a round screw top ,atte blue storage case (which matches the finish of the IEMs), a very nice cable with interchangeable connectors, the connectors for said cable (3.5mm, 4.4mm and 2.5mm) and a disc with the additional tips. In total we get 6 sets, 3 sizes of “vocal” ear tips (which are blue) and 3 sizes of “balanced” ear tips.

In general the presentation is elegant, with the needed accessories included, and does give a more premium feel than other packaging.



Build and aesthetics…

The IEMs are very compact and opt for a matte blue plastic shell along with a CNC carved aluminium faceplate, meaning they are also very light. The nozzles are rather short yet the tips have quite a shallow fit onto them, which makes them seat nicely inside my ears, getting an easy seal and no discomfort or fatigue over longer periods. Of course, my ears are unique and so are everybody else’s, so comfort will be a very personal thing but I have to say that they are something that I find very comfortable.

As said in presentation, the cable is nice, using a black and silver wrap inside a clear finish for each side, which in turn, is wrapped below the divider. The cable feels nice and is not overly thick, nor overly thin, it is just around where i like it.

The cable uses metal hardware at both ends, with a metal divider but clear plastic chin slider. However, the only thing I found strange with the cable is that the 3 included interchangeable connectors are finished in a white matte plastic. I have absolutely no issue with them being plastic, they are nice to the touch and feature the Letshuoer logo, yet, if we are going plastic, why not make the a blue that matches the IEMs (and storage case) or just go with metal and have them match the rest of the cables hardware. It is not really a complaint, I still think it is a very nice cable, it just seems to be a 0.1% thing that could have added even better aesthetics.



Sound…

All tracks mentioned are clickable links that allow you to open the reference track in the streaming service of your choice (YouTube, Tidal, Qobuz, Spotify, etc.)

I have to say that the S15 are quite a step away from the S12, which can be a good or a bad thing, depending on what you want from the IEMs.

There are two things that I find stand out straight away when comparing the two models, which I guess shouldn’t really be compared as they are not really in the same range, but seeing how much I love the S12, how could I not?

The first is the fact that the higher ranges of the S15 reduce their presence quite a bit in comparison. After playing with the two types of included tips, I found myself enjoying the “vocal” tips much more but I didn’t find that either of them really brought the upper ranges up, just that the “vocal” option seemed lusher in its presentation with my favourite female vocals.

The second is detail, especially in the low end. I don’t think that it is the fact that they are much more detailed per se, I just find that the details have more authority and separation, without becoming in your face. There is certainly no “fake detail” from upper range boosts with the S15.

But anyway, let’s get on with my usual test list and opinions, starting off with our look at the graph in comparison to my usual preference curve:



Starting off, as always, with the subbass and my obligatory listen of “Chameleon”, there is certainly a presence of subbass but it is not overly boosted. While the subbass is there and is capable of rumbling, I would say that there is actually more focus on the midbass. Again, that doesn’t mean that subbass is lacking, at least for me, there is not a huge amount of rumble in things like “Royals”, although that “dirt” that I associate with the subbass of this track is easily appreciated.

As I just said, I find that there is more of a focus on a punchy midbass than there is on a rumbling low end and I have to say that I am impressed. “No Sanctuary Here” is very punchy and present in its midbass yat it is clean and remains totally controlled at all times. It is also very detailed and, as I said a moment ago, more “authoritative” in those details than on other planar sets that I have heard. I have no idea if it is due to the PFM or not but I think this is the most “dynamic driver” like midbass I have heard from a planar IEM.

Moving into the mid range, I find that the there is a continuation of the midbass clarity. In fact, the mid range is very similar to that of the S12 yet, again, I find it to be slightly more textured and have more weight to it. The timbre of instruments is very natural in the lower and mid ranges, with acoustic guitars having plenty of body but without being overly boosted in those lower ranges, or at least not giving the impression of being overly boosted.

As we start climbing into the upper mids and then the lower treble, this is where the S15 differ quite a bit from the S12 or many of the other planar IEMs that are on the market at the moment. Between 1.5kHz and 2kHz, there is a presence that compensates the lower end but then it drops away, being more on the darker side in these upper ranges.

If you are someone who like a lot of clarity and air in the upper ranges, with an emphasis on vocals, then the tuning of the S15 is not something that will really match your preferences. However… although there isn’t much presence in the upper mids and treble ranges, the clarity of the lower regions works very well to avoid the general sound signature becoming muddy or hazy in general.

Vocals are smoothed over yet they are not dark and distant, they come across as having a lushness to them, as I mentioned in the lower ranges, that is actually very pleasant to listen to. While I would never choose this tuning of the higher ranges for me personally, I was very surprised to find how much I actually enjoy listening to the S15.

Sibilance is avoided, as is any harshness in the upper ranges, yet, again, it does not push things so far back that they become too dark. It is an approach that I think moves us away from focusing on minute details and more into the relaxed listening mood. Saying that, it is surprising how many details can be appreciated in the lower ranges, without any peaks that greet us with a fake sensation of detail. In other words, there is no emphasis nor impression of “look what I can do”, it is more of a case where they simply do their intended job and they do it very well.



Conclusion…

I am surprised to find that the S15 are as enjoyable as they actually are. I had seen graphs of the response before listening to them and I was really expecting a midbass focused dark mess.

While they are focused on warmth, they don’t overdo it in the bass ranges at all. On top of this, they are very detailed and perform very well in the lower ranges, making for a very natural timbre of instruments in these frequencies. Yes, there is a lack of upper shine and air, so if you are looking for a brighter set of IEMs then these probably won’t fit the bill, yet they manage to still be a very enjoyable set of IEMs that I find to be a very pleasurable listen.

Again, at the risk of repeating myself, I feel that the the S15 have the most dynamic driver sound to the lower ranges and mids that I have heard in a set of planar IEMs and I like it!

____
As always, this review is also available in Spanish, both on my blog (www.achoreviews.com) and on YouTube (www.youtube.com/achoreviews)

All FR measurements of IEMs can be viewed and compared on achoreviews.squig.link

All isolation measurements of IEMs can be found on achoreviews.squig.link/isolation

Letshuoer S15 Review​

Full written review

​

Letshuoer S15​

Intro​

Today I am reviewing one of Letshuoer’s latest within their lineup of planar magnetic iems, the “Letshuoer S15”. Letshuoer is one of those brands that seems inclined to try something new, something different, possibly something that not many of us have heard of. This is the case with this wonderful new planar magnetic iem, further in the review I will certainly expound on that. Back to Letshuoer, there is also something different about this brand. From an outside perspective that is, and perception is reality of late as we’ve seen different tech housed within their lineups. I have very much enjoyed everything I’ve tried, tested, or owned from this brand.

Letshuoer​

Shuoer Acoustics was formed in 2016 by Danny To and Jeff Wong. Together, along with a team of people, they’ve built their company into what it is today. You can read a little bit about some of these folks HERE. Letshuoer which began their journey branded as “Shuoer” has created many fine earphones that have truly stood the test of time. I myself have reviewed only three of their sets, the Letshuoer S12 Pro (S12 Pro Review), the Letshuoer DZ4 (DZ4 Review) as well as the S15 which I am reviewing here. I’ve also “tried” a few more of their more expensive sets that I simply don’t have the funds for, and I’ve walked away flat out impressed every time. I also own the Letshuoer D13 which is an underrated iem and a fun one at that. They have some massive successes in the business with the Letshuoer Tape & Tape Pro, the D13, Soloist, DZ4, S12, S12 Pro, EJ07, EJ07M, EJ09, the Conductor as well as the Cadenza 12 among many others. Each having its place among some of the great sets in their relative price points and each having its own special tech. Obviously, Letshuoer makes sure to exhaustively work on a product until it is finished and complete. I can respect that. Maybe one of these days I’ll be able to test out some of their high-end gear for review. Till then I’m very pleased with what I’ve heard.

S15​

The Letshuoer S15 comes with quite a bit of fanfare as it’s a direct sibling of one of the most impressive and heralded series of planar magnetic earphones on the planet. The S12 was surely one of the biggest success stories in the entire audio world. Then Zeos came out with a collaboration effort and released the Letshuoer X-Z Review Z12 which was another smashing success. We got a couple different versions of those and then Letshuoer decided to trump them all with one of the better planar sets under $250 with the Letshuoer S12 Pro. To say that the S15 has a lot to live up to is an understatement. Another thing is that the S15 brings with it some skepticism because of the addition of what they called a “passive radiator” which was later explained that it isn’t a passive radiator at all, but instead it’s a pressure relief, but I’ll get into that later. The point is, the S15 better bring it. This is quite a price jump ($330) and it’s more than flirting with the mid-fi scene. The number of great sets between $300 and $400 is silly folks. We shall see…

Thanks​

With that, I thank you for reading this review and hope it helps you out. Truly. That’s why I even do this, along with the fact that I love writing about the subject of personal audio. Before I dive into this review, I must thank Letshuoer for providing the Letshuoer S15 in exchange for a full review and feature at Mobileaudiophile.com. Let it be known, I receive nothing in compensation for this review or for any sales of any units of the S15. I am not affiliated with this company or any company that I review for. Please rest assured I would never bind myself to any agreement like that… Ever! Nobody has ever, nor will ever pre-read any review of mine. I would rather not review at all if that was the case.
Lastly, please understand that what I write are my thoughts, my experiences, and my words… end of story. However, we all have our own biases and in a subjective game such as reviewing, those biases can surely appear in my writing, I am a human being after all. I promise to put you (the buyer, consumer, hobbyist) first and tell you my exact feelings to the best of my ability. With that said, the Letshuoer S15….

Non Affiliated Purchase Links:​

–Letshuoer
–Zeppelin & Co.

Disclaimer: I received the S15 from Letshuoer in exchange for a full review. I have not received any payment or any other form of compensation for this review. This set is a sample iem. Letshuoer 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. Thank you to Letshuoer and thanks for reading.

Gear used for testing​

–Ifi Go Blu

–Hidizs S9 Pro Plus

–Moondrop Dawn 4.4.

–iBasso DX240 with Amp8 MK2

–Shanling M6 Ultra

Packaging / Accessories​

Unboxing​

Letshuoer does a great job of packaging their earphones. Well, at least any of the sets I’ve checked out. The S15 is no different. I love how Letshuoer got kind of creative with the unboxing, it just adds an extra short-lived element of anticipated joy. Okay, maybe it is just me. Anyways, the S15 arrived at my house in a good size rectangular box covered in a thin cardboard sleeve. There really isn’t a whole lot to say about the look other than there is a design on the front similar to their promotional material.

Anyways, remove the sleeve and you are presented with an even more utilitarian box. Open the box top and you’ll see the dope looking Letshuoer S15 earphones sittin’ pretty staring back at you in cardboard/foam cutouts. Lift up the foam layer and you’ll see an envelope with some reading material as well as a poster of the same promotional image we’ve seen relating to this set. So, as I was looking over the box I realized after far too long that there is a drawer on the lower half of the box. Open the drawer and you’ll see the case as well as the modular cable adapters also sitting in foam cutouts. Inside the case you’ll see the cable as well as the eartips. Not bad Letshuoer! I feel the contents are good enough for a higher price tag.

​

Eartips​

So Letshuoer added in six sets of tips in total. Or two different varieties of tips as well. The first set of tips is a semi-wide bore set of white silicone tips (S, M, L) with a pretty stiff stem and a firm flange. I’d say reminiscent of KBear 07 tips but with a slightly thinner stem and slightly less firm flange. They are very good tips. The second set of tips is a light blue set (S, M, L) of wide-bore tips. These are actually the tips that I used the most during my time with the S15. They’re a wide-bore, shallow fit, firm flange type of tip and they look great on the S15. More importantly they actually sound good too with the S15. I’ve used about every set of tips in my arsenal on the S15 trying to find the best fit. Some of my favorites include the KBear 07, JVC EP-FX10, and Divinis Velvet. However, for review purposes and because the fit is silly good, I simply chose the included wide-bore tips. They work like a charm for me.

Carrying Case​

The carrying case is a hockey puck styled case with a threaded lid that simply screws on & off. The look of the case is not the most luxurious as it’s made out of plastic. I do like the coating they use on it. It’s this matte blue color, similar to the S15 shell, and has this rubbery feel that is very nice to me. I have no reason other than that of why I like it. It has a satisfying feel, for whatever reason. Probably not the most robust and Letshuoer probably could’ve sprung for a better material for the case but… oh well. The truth is, I haven’t used a carrying case in years but for storage at times. So, it doesn’t bother me too much. However, for those who value a good case just know that it isn’t too large, the threaded top unscrews with ease (shocker), and you may be able to fit a small dongle dac inside as well.

Cable​

The included cable that came with the S15 is a very nice cable. Similar to the cable provided with prior iems but this one is a bit fatter and also has modular connections (awesome). To be exact, the cable is a .078 2-pin 216 strand mono-crystalline copper cable which comes equipped with 3.5, 2.5 & 4.4 right angled modular connectors. I don’t find the cable to be microphonic at all and find zero reason that anyone would “need” to replace it or cable swap. It is a very nice-looking wire that pairs well against the silver and baby blue of the S15 earphones. The color is a braided mix of brown and white and I really dig it.

The actual function of switching out the modular connectors is about as easy as it gets too. Simply line em’ up and push the connectors on. Now, not all modular connectors are created equal. For instance, I find Letshuoer’s cable connector to be much better than something like the Tripowin Noire for example. The connection is tight and rigid and never comes off. The included cable also has durable enough and pretty robust hardware for a set at this price. I think this is a nice addition and I’m glad to know that Letshuoer understands that a good cable is important to us hobbyists.

Build / Design / Internals / Fit ​

Build Quality​

This is one area that may be a point of contention for some of you. In fact, I see it going one of two ways. First off let me explain. The Letshuoer S15 is made by “HeyGears” by way of 3D printing. HeyGears is a well-known company who has assisted many brands with such needs. The material is advertised as a “3D printed Resin”. But not like the typical resin you’d see nowadays… Obviously. This is a very cool feeling & matte baby blue colored material that almost has a rubbery feel to it. Just like the material used on the Letshuoer DZ4. Same stuff. I think I like it. It doesn’t get cold, it’s super light, and it looks very cool in my opinion. However, I said this’ll likely be a point of contention. I do fear that many folks will see the price of the S15 and wonder why there isn’t a more robust material. That said, I really think it is a trendy and durable material that many will enjoy. There’s also a small vent hole towards the back of the unit as well. The nozzles are average in length and are made of the same material as the Shells. Again, the entire acoustic structure and internal cavity has been 3D printed to specific parameters to keep the tuning principle intact. It’s a good build, whether one hates it or not. It’s obviously durable, impervious to corrosion or attack from the elements, it’s very lightweight and also, it feels good to the touch.

​

Design​

This is an area that I would’ve thought would garner across-the-board approval. Apparently not everyone feels this way. Maybe my eye isn’t as good as I thought it was. At any rate, I think this set looks really cool. I love the understated, non-logo havin’, simplistic yet modern design language. As you can see the faceplates are made out of all alloy. That’s “Anodized Aluminum” to be exact. The faceplates are all silver in color with raised above flush little waves creating a pattern on the faceplates. Those patterns are CNC carved and then sandblasted & anodized. The Shells themselves are 3D printed, with a matte baby blue color and an ergonomic shape. Listen, in the looks department it isn’t the best look I’ve ever seen but it also isn’t even close to the worst. For me personally, I think it looks pretty darn sweet but some folks on Facebook remarked that they didn’t appreciate it too much. I suppose it only matters to the person buying them.

HeyGears crafted shells
The S15, after thorough optimization of its chamber structure, strikes a perfect balance between form and function. In collaboration with the class-leading 3D printing company, HeyGears, the shell is crafted to ensure a lightweight and comfortable wearing experience. The faceplate is made out of aluminum-magnesium alloy which is CNC precision carved, sandblasted, and then anodized. Not only does it look unique, but it is also resilient against scratch, smudge, and everyday use.
Letshuoer Promotional​

Click to expand...

Internals​

This is once again (for whatever reason) another point of contention. First off, Letshuoer went with a 3rd generation 14.8 mm Planar Magnetic Driver as well as a 6 mm Passive Filter Module which actually isn’t a driver or a passive radiator like some (me included) thought it was. Well, if you read their promotional at the beginning that is what they called it. Obviously, a passive radiator didn’t make any sense in this application, much the same as the Letshuoer DZ4 where we also had some groaning from some people screaming that they were being lied to. Or something.

​

PFM​

The “R-Sonic Passive Filter Module”, or “PFM” simply acts as a pressure relief for when the sound pressure level begins to rise. That’s it. When the SPL is a bit stronger than the PFM membrane is activated which ultimately pushes or pumps the energy away and out of the vent holes within the same acoustic cavity. This also is said to reduce the excursion or movement of the actual planar driver which will also reduce listening fatigue for these situations, or so it is theorized and patented. When the SPL is not enough to activate the PFM then it will simply sit idle. There ya go, it all makes sense. I simply think there was some confusion when the S15 was first advertised. I fell victim myself and posted that this set came with a passive radiator. Now we know…Moving on.

Thankfully everything seems to work as intended and I get no undue resonances in the sound field. At least nothing which I can hear. Also, this set sounds great in my opinion, so I think Letshuoer is doing something right. Letshuoer also uses “dual sound tubes” which is a well-known method of filtering different parts of the frequency allowing each 3rd of the mix to come across coherently.

R-Sonic Passive Filtering Module
To achieve a more natural and comfortable sound reproduction, LETSHUOER’s research and development team poured every ounce of their technical know-how into combining the 14.8mm dual chamber planar magnetic driver with LETSHUOER’s proprietary ‘R-Sonic’ PFM technology. Breaking through multiple technological barriers, the S15 is another outstanding entry into LETSHUOER’s planar earphone roaster, which delivers an unparalleled audio experience.
Dual Acoustic Tubes
The dual acoustic tubes filter the sound on different frequency bands, allowing the highs, mids, and lows to shine through proportionately and seamlessly. Every detail is carefully tuned, presenting an excellent balance of audio quality.
Letshuoer Promotional​

Click to expand...

Fit / Isolation​

The Letshuoer S15 takes a minute of fiddling to get the right fit. This all depends on the eartips that I choose though. Using a fatter and more rigid shallow fit tip like the blue set that comes with the S15 I have zero issue at all. In fact, they fit rather perfectly. As I say in every review; I don’t know how they are going to fit in your ears. This section is almost pointless for review purposes. I will say that the S15 does have an ergonomically polished build that does seem to nestle right in my ear very nicely. As far as isolation is concerned the S15 are simply average. I don’t feel they attenuate outside noises but at the same time they do block out enough. There really isn’t any sound leakage to the outside world either. All things considered; this is a solidly built set that has comfort as a priority.

Drivability​

Mobile Listening​

Letshuoer states that the S15 has an impedance rating of 30 ohms and a sensitivity of 106 db’s. What this translates to is a set which can get adequately loud, even on less powerful sources. Don’t be fooled though, there is some benefit to giving this set some more power. In fact, I don’t think you receive the full potential of the S15 without at least decent output. By decent I mean 100mW or more I would say. Best guess.

Listening with the IFi Go Blu presented a nice sound on 4.4 balanced. I felt it was a more open and more precise sound then listening on 3.5 single ended, to a slight degree. The synergy is great with the Go Blu’s CS43131 dac chip and its good power output. The neutral leaning warmth of the Go Blu reacts wonderfully with the S15. Using the Moondrop Dawn 4.4 I found a great pairing too. The power is enough to really energize the planar magnetic driver and also produces very nice synergy. However, I actually liked the warmer Hidizs S9 Pro Plus (ES9038Q2M dac chip) which gave me a relatively smooth sound that has great dynamics with the S15. It’s a good mix of tonalities. Of course, this determination is subjective to me.

Daps​

Listening with either my iBasso DX240 (ES9038 Pro chip), or my Shanling M6 Ultra (AK4493SEQ chip) I got two different and distinct sounds that married well with the S15. I’d say I like the M6 Ultra a bit more as it has that warmer, smoother and velvet sound while coming across very resolving and dynamic. I felt there was a hair more of a metallic tinge to the very crest of notes with the DX240.

At the end of the day​

I feel, so long as you have a decently powerful dongle dac you should be fine with the Letshuoer S15. This is not one of those planars which needs a million watts of power to shine. Yes, the more you can give it the better, but I do think there is a cap to that. Granted, I’m sure the S15 can handle a lot but the benefits it seems begins to diminish at a certain point. This is a nice sounding set that seems to react and synergize pretty well with most sources.

Sound Impressions​

Note: all critical listening was completed after roughly 25 hours of burn-in. To be honest, I really don’t know if this helped or not because I loved the sound out of the box. So, I don’t know if burn-in is really needed. I usually complete at least 75 hours on most sets, but during my check up on the S15 I found no real reason to go any further. I used flac or better music files for all listening, I used the stock shallow bore tips, stock cable and I listened mainly on 4.4 balanced on each source. Primarily the Shanling M6 Ultra.

Great way to hear my music!​

Listening to the Letshuoer S15 is a great way to hear my music folks. I don’t want to come across as though this is the best thing on planet earth, but the sound is ridiculously good. Let’s just get that out of the way, no confusion. The S15 is a very nice sounding set to my ears. Does the S15 compete with other sets of different driver configurations within the price point? Now that is a more nuanced conversation. For me yes, but for you? As far as planar magnetic earphones go, I find the S15 to be engrossing and unlike any I’ve ever heard. Of course, the price is definitely something to consider. So, another question I will try to answer is if that cost is reflective of the S15’s worth. Again, very nuanced and not simply a cut n’ dry answer. Also, these are my own personal and completely subjectively objective thoughts and my own preferences. So, I will do my best to explain what those preferences are so you may have some sort of a gauge.

What does it sound like?​

The sound of the S15 comes across as warm/neutral, or warmer with a slight tilt to neutrality. It’s warmer listening with the M6 Ultra and slightly closer to a neutral sound with the iBasso DX240. However, there is always that hint of cozy warmth to add fullness and realism where needed. If I were to categorize the sound, I’d say it’s a warmish U-shaped sound or even a warmer W-shape sound. Somewhere between the two maybe.

The sound has this solidly lean-lush note weight that carries good but smooth note definition throughout. I’d call it lusher than it is lean. Some areas of the mix are more defined than others though. I find the sound to be punchy, thumpy, but also structured, never sloppy, and decently detailed too. Depending on the track being played and what area of the mix we are talking about of course. Resolution is very nice for the tuning. The stage leans more holographic in its presentation than it does flat like most planar sets. Imaging is good and sound layering is fantastic. Macro-dynamics are full sounding across the board and even lower volume micro-dynamic shifts come across agile and clean.

Nothing inherently bad​

I don’t hear anything that jumps out at me as inherently bad. Possibly those who yearn for an ultra-lean, snappy and ultra detailed response may not appreciate the S15 on every track. Maybe those who want a bright and crisper sound will want to keep looking. But honestly folks, I really have enjoyed my time with the S15. I think that (for the most part) the sound is smooth, coherent and well controlled. The sound is transient swift yet there is evident fullness within the body of a note. This note weight and clean warmth helps the atmosphere in my music to bring some emotion to the sound. The biggest thing is the warmish and effortless musicality that I hear which invades my senses folks. Probably not for everyone but for those that enjoy this type of sound… You’ll be impressed.

Quick look: Sound between the 20’s​

The bass is surely emphasized and holds a large part of the focus of this set. I would say we have a mid-bass emphasis, but rest assured the sub-bass and mid-bass do well to share the lower half of the mix. It’s pretty big and pretty fast and able to handle fast bass passages fairly easily. The beauty of the bass is the full and round note delivery though.

The midrange is more forward than it isn’t with great presence in the mix. There’s some depth to the midrange and some good and dynamic energy that is wide and immersive for vocals and instruments. Males have plenty of authority and aren’t really recessed. Females are a hint more forward; they have some warm bodied shimmer with a softer vibrance but without going overboard. Females are so very easy on the ears.

The treble comes across as softer in note definition but nicely emphasized. I find the treble to be a very nice piece to the puzzle without ever adding any peakiness, glare, or sibilance. The treble will not please treble heads or those who struggle hearing this frequency, but it does lift up the rest of the mix quite well, in a coherent way. Or just enough. The stage is wide and even has good depth, again, Imaging and layering of those images is really great for a planar. Also, per the softer, fuller, warmer tuning… Detail retrieval is better than it should be.

If this is all you read​

If this is all you read, then just know that (in my opinion) the Letshuoer S15 is simply one of the best planar magnetic earphones that you can buy for under $400. The entire mix is accounted for and well-tuned with plenty of vibrance, emotion, and yet capable of a very nice technically adept sound.

Bass Region​

This is a very nicely done bass region for a planar set. No doubt. I consider planar bass to be a good middleman between a leaner, speedier & drier balanced armature type low-end, and the organic boom and reverberant authenticity of a dynamic driver. Folks, the S15 is the epitome of this sentiment in my opinion. Truly it has a deep enough grumble and rumble to hit those decently extended sub notes, and it has tactile speed and punch as well without coming across too knife edged, artificial, bloated or muddy.

Absolutely smitten​

There’s this elastic and rubbery malleability that adds realistic weight and body to the texture of a bass drop, bass guitar riff or kick drum boom etc. There’s also a warm roundness which holds the Integrity of the timbre through a note and releases cleanly after the efficient sustain forming a resolute note definition. It isn’t falsely over-saturated, over resonant, it isn’t fuzzy, or pillowy, and isn’t too vibrant in its tonal color. It isn’t dry, and damn sure isn’t weak. This bass is nicely separated with almost the same type of naturally occurring timbre of a DD. Really. Not quite there but similar to my ears. At least on the initial attack that is. The bass has a very clean and hard lined attack edge at the crest of a note and a short lived sustain. I don’t want to oversell but I also don’t want to undersell, and so I may be in a precarious situation with my words. However, I’m absolutely smitten with the sound of the S15, and the bass is one 3rd of the reason why.

Sub-bass​

The sub-bass reaches deeper than I thought it would be able to while still being able to coherently deal with the rest of the mix. The sub-bass strikes a great balance of cohesion and dynamic amplitude. There is a dynamic balance on this set and the sub-bass quite literally is one of the cornerstones or foundational anchors to that dynamic balance with the rest of the mix. Now, the S15 is certainly capable of some rumble down low and has plenty of palpable haptic feeling to the sub-bass which comes through to the listener as vibrational energy. It adds some nice depth to the sound. I still wouldn’t exactly equate the sub energy of the S15 to the feel of a good Dynamic Driver, but in some ways… it’s just as good. In its own planar way.

In the track “Groove” by Ray Wylie Hubbard, the S15 gives a gravely and very rumbly performance as the bassline sets the tone for this track. I use this song probably more than any other to describe bass in my reviews. I know what it’s supposed to sound like, I know what deep sounds like on this track, I know how tight the reverb can sound or what it sounds like when it’s muddier and sloppier. The S15 takes this sonorous sound and gives a good low-pitched rumble that doesn’t have any overhanging and lagging harmonics. Instead, it is easily distinguished and discernable with a bigger than moderate low toned and tight 3D presence.

Mid-bass​

Moving on to the mid-bass, I do feel the very slight majority of the low-end volume is in this region. The mid-bass has some real nice slam with a very robust and warm boom for bass drops and a good and full droning growl for bass guitars. For the most part anyways. Kick-drums like those in “Billie Jean” by Weezer (Michael Jackson cover) sound very hard hitting and decisive with a booming and hollow thud that’s met with a nicely tacky edge. I don’t hear as much of the resulting decaying harmonics from the kick drums but the S15 sounds really nice to my ears. The S15 has great cohesion and depth to the bass and sounds very good against the neutral/warm backdrop of the rest of the mix. It’s a hard-hitting density that couples well with the lush airiness in the overall tuning. It’s agility-rubbery-textured meets rigidity & bold authority.

Mid-bass cont…​

Another track is “Feelin’ the Miles” by The Wilder Blue which has a warmer atmosphere to it. There’s a sick bass guitar riff which literally carries the tune. I love how the S15 can replicate the fullness of this instrument and does so with great tonal color and actual dimensionality. There is something to the sound which is palpable enough to mimic proportions. It’s full, meaty, it’s emphasized too. However, that emphasis does not overtake the rest of the mix. The percussive elements on this track are many and each is displayed very cleanly, with an organic & lush try at precision. I also like “All My Life” by Lil Durk as the mid-bass has a well composed boom and then gets out of the way. It colors the mix without clouding the mix and not to a detriment. The bass drop on this track is hard and not pillowy at all. It’s structured and not muddy. It’s macro-detailed and not one-noted. Smoother than it is crisp and has great note weight without adding a veil to the sound.

Further thoughts on the bass region​

From the moment I put this set in my ears I have enjoyed the low-end of the S15. I would call it the “darling frequency region” of the S15, but that is very much debatable. I love how complete the bass makes the S15 sound. Never too much to become gaudy and over-resonant or over-saturated, but big enough to have borderline Bass-Bois bobbing their heads. Not quite bass head to me though. The bass is simply a well-represented & fun sounding bass. Also, it isn’t technically deficient. I feel this bass is great for fans of hip-hop, edm, even jazz and any other genre which relies on a dense and authoritative bass region but doesn’t go overboard.

Downsides to the Bass Region​

As far as issues which may arise in the minds of some of the folks in the hobby, I’d say that for sure the S15 may have too much low-end emphasis. Those people who enjoy an ultra-quick, drier and transient rapid type listen will feel this is a little too much. I’m sure. The other thing which may be an issue in the bass range is that there are sets in the price point which can do a fun type of bass a bit better. There are DD’s which can perform a slightly more organically authentic sound and can do so with more feel to the sound and boom. However, I say that but what the S15 does is it carries this low-end in a way that has some measure of exactness without losing its tonal color or heft. There is density to it and a juicy element that still holds tight to its depth and roundness. But there’s also a measured approach to the bass that can easily take faster bass tracks just as well as it can perform a booming bass drop. It’s flexible, rubbery and It’s a nice bass for a planar set folks. Who am I kidding, it’s a great bass for any driver configuration.

Midrange​

Oh, my friends, I love this midrange! What an inviting and sultry sound that holds my attention so well. The midrange is the type that sounds forward in the mix with plenty of warm air to the sound yet still comes across with some splashes of healthy separation. I call it U-shaped, but the midrange gives me doses of a W-shape sound. The mids are more neutral than they aren’t but keeps this slight ubiquitous warmth which adds so much to the sound. The nice thing is that this warmer airiness or lush openness is not at the expense of note weight. In fact, the weight to the midrange sounds very natural. Of course, this is my interpretation of what “natural” sounds like. Perhaps just a tad less weighty than natural but certainly in a “lean-lush” way with a very technically adept sound that is just as transient-swift as it is atmospheric.

The crazy part is that the bass doesn’t add this veiled weight to the sound. The S15 depends solely (it seems) on its natural body which completely separates this set from other planars in my opinion. The timbre is very nice, especially for a planar iem. To be completely honest, I absolutely dig the vocals here! I mean I REALLY ENJOY them! Now, it isn’t the Penon Fan 2 type of warmth, forward, & meaty vocal, or the Aful MagicOne type of holographic neutral forward vocal either. Instead, it’s this type of delivery that manages both smoothness & non grainy crispness. I feel the S15 does whatever the track asks it too with hints of coloration, dense malleability, and a completely musical character.

Lower-midrange​

As I said, the low-mids have some carry over from the bass region which adds just enough body to a male vocal for me. I would usually like a hint of more warmth here but I’m not complaining because most male vocalists come across with good presence in the mix and are prominent while maintaining good placement. Listening to the raspy voice of Chris Stapleton in the track “Higher” (from his latest album) shows off the smooth texture of Chris’s voice in less dramatic parts of this song. As his voice raises, the natural knife edge to his voice comes out but the S15 maintains its control over the timbre on these occasions. I don’t hear that planar electric fuzz and grain at the note edge, but instead I hear a constrained and controlled intonation to his voice with a smoother and more round note delivery.

A lower pitched baritone like Avi Kaplan in “On My Way” has a very nice sound as the S15 keeps a strict control over his voice with a deep and crisp sounding vocal treat. His vocals simply sound clean. Higher pitch male voices like Noah Kahan in “Bury Me” sound a bit more forward in the mix and have a nice sounding intensity or glimmer, while his voice also sounds a bit leaner than lower pitch vocalists. There’s always a certain density or solidity which brings an otherwise artificial sound (Noah’s voice) back to earth. The sound is more neutral on this track and some of the lower pitch warmth is not affecting his voice as much. His voice almost has a luminance to it which isn’t perfectly natural sounding but very nice to listen to. Also, what’s natural? His voice sounds amazing folks.

Upper-Midrange​

The upper midrange is where most female vocalists reside as well as a lot of instrumentation. As far as female voices, they come across more forward in the mix than males though the difference isn’t great. You know what, I just have to say before moving on… Female vocalists sound freakishly good for a planar iem. In fact, I’ve never heard a planar sound so full and so enveloping in my time in this hobby. Okay, carry on… Females have some shimmer to them and mostly come across lushly open (if that’s a thing… it is now) and have some added vivacity while never carrying over into harsh pinna glare. I find the S15 does an admirable job providing a robust female voice with actual texture to them. This is not always the case. Some iems will come across even warmer and they will have that juicier sound and they will have that great texture. However, the S15 does the same (juicy, texture) but also with a more naturally open sound, more non-brilliance airy while still maintaining that smooth and engaging quality. Females still have that lean-lush but also solid note weight and sculpted smooth presence that works very well.

Eerily Mesmerizing​

Gracie Abrams has a more soft and feathery voice on the track “Will You Cry?”. The S15 is well able to surround her voice and give it some weight while holding tight to that feathery and lite inflection and tone. She sounds nice. Taylor Swift sings “The 1” off her “Folklore: the long pond studio sessions” album released recently. The S15 gives Taylor a black canvas to work on as her voice is almost hauntingly sweet and smoothly defined with a very nice body to her vocals. Her tone is dimensional, natural in her intonations, but eerily mesmerizing and emotionally inviting. A lone trickling piano arranges the melody along with slight percussion etc. The piano notes are bouncy, vibrant enough, but are also stretched out in body which arranges the mood of the song. Like reminiscing of “what could have been” but with a smile on her face. This isn’t a song review though. However, I love the S15’s ability to convey not just difficult and fast paced tracks, but also slower and more emotional tracks like this one. Her voice is very melodic with the S15 having almost perfect tonality for this song. To me, females in general sound very nice. No doubt it won’t be for everyone (my constant disclaimer), but the S15 will please many.

Instruments (in general)​

Piano in this region has a nice root tone and the residual harmonic resonance sounds nice to me. It sounds real to me. There is a 3D type placement of the stage and a 3D rendering of each instrument and voice which is very revealing. Acoustic guitar has a natural sound with easy to pick up details especially on acoustic tracks. Electric guitar is easily digestible without that sheened-out glare. Even sustained in distortion I find it very enjoyable and never really harsh. Percussion has a very nice luster in most any track. Especially snares which pang with a snap to them. Cymbals have that bodied and warm “chisk” & tambourines (for the most part) chime and shake with good energy. Violin goes from nicely brassy and bright with a sharp edge to warm and almost wooly, again with adequate note weight and definition. Friends, I’m not going to go through every random instrument I’ve heard. These are just very broad and general descriptors which come from my notes taken from songs on my Playlists. Just know that I didn’t hear anything outright “off” to my ears.

Downsides to the Midrange​

When picking apart the midrange to find subjective gripes or issues I suppose I could say that there are instances when the right track can become a bit too sharp. Too few and far in between to call this a “con” for me but for someone else it may be a deal breaker. Especially for those ultra thick, warm/dark midrange lovers; they may not appreciate the overall tone & timbre of the S15. This isn’t the most technically savvy and most detailed midrange. Though I would say it is just fine. However, I could see some folks wanting a leaner, snappier, more technical midrange. Some folks may want a longer sustain to the harmonics that planars don’t necessarily have all the time. The tighter transient behavior of the S15 actually can come across atmospheric though. Of course, it isn’t perfect. However, at the end of the day I think the S15 sounds great in this region. It’s warm/neutral and lean-lush note body has great note definition, above average resolution and is great for detail retrieval.

Treble Region​

The treble presents a slightly less lively top-end but still has a pleasant amount of emphasis which balances very nicely with the rest of the mix. Almost leaning dark but is saved by some milky luminance that adds just enough smooth levity to the sound. However, I would not consider this a sparkly or brilliant treble region. Treble heads will want to look elsewhere. Still, there’s good coherency of sound between the treble, mids, & bass. I feel it is lifted enough to add a mellow but natural vibrance to the upper mids, some snap and energy for percussive instruments and is able to slightly uplift the overall sound. Enough so that I wouldn’t call it darkish or subdued. I’d like to say it’s just enough without ever becoming fatiguing to my ears. In fact, even when raising the volume, I didn’t hear that screeching treble sheen or shout. Letshuoer made sure to tighten up this region with smooth compactness. So no, it isn’t the most boosted, but it is a nice sounding and musical top end. I feel there is some improvement in harshness from previous versions, like the Letshuoer S12 and S12 Pro. I hear an evident reduction of actual treble air compared to those sets but what I’ve gained is note structure and better bodied note definition.

An improvement​

The highs on the S15 have very good resolution and they come across with good bite. There is ample energy that is rewarded with decent haptic feedback which does add another dimension to my music. Don’t get me wrong, this isn’t a treble heads paradise, but it is a marked improvement (in my opinion) in the Letshuoer lineup from earlier sets. The treble comes across a bit smoother and not as edgy and grainy over long periods and everything is just “kept in check”. There is a healthy balance of warm shimmer with good treble presence and a nice ability to expose and highlight the subtleties within a track. Not a detail monster though. It’s more lush, authoritative in its richer note structure which isn’t exactly a precursor to detail retrieval. Still, it isn’t bad by any stretch. I feel for those people who would’ve liked less treble emphasis than something like the S12 Pro would likely appreciate what Letshuoer did on this set. There isn’t any forced resolution or any pushing of the treble quantity in attempts to add some air, extension, or details, which at times can make the sound artificial.

Examples​

The great thing about this set is that the treble fits the other frequencies very nicely. Somehow. Again, the treble balances very well and doesn’t seek to overtake any other part of the mix. It simply works in a smoother bite with enough slight brilliance, and I think the result is great. The treble is transient-snappy but does so with this fullness, which flattens the perception though make no mistake, the S15 can take on the quickest tracks with relative ease. Listening to Billy Strings “Secrets” is a good example. The S15 easily replays Billy’s breakneck speed of his guitar and banjo and does so effortlessly. Every note is accounted for. The cadence is on point, the timbre sounds awesome, and I don’t hear any blending of sounds at all. “Bishop School” by Yusef Lateef is another track I use quite a lot as there is a lot of treble activity within it. I really enjoy how well the S15 is able to create space and delineate each instrument in this lusher environment. Granted there are other sets in the price range which can also do a great job on this track with more bite and tactical ability. Basically, it isn’t a miracle set and it doesn’t have the most brilliant sound up top. Still, I am impressed when I look at the entire scope of the S15 sound.

Extension​

Extension is also pretty nice on the Letshuoer S15 as we have a reasonable amount of info obtained past 10k. I wouldn’t call the S15 the most extended, but it plays very well against the overall mix. For instance, the secondary harmonics of a cymbal strike doesn’t have a splashy sustain and doesn’t come across digital, or like a mishmash of treble sheen. I don’t find them to be attenuated either. Warmer in body and natural in note portrayal. I find extension nice. Not the best, but nice. It isn’t a detriment, let’s put it that way.

Downsides to the Treble Region​

What are the problems with the treble? Obviously treble heads will want an even more naturally weighted and haptically vibrant treble that’s even airier. They’d probably be looking for better fine micro-nuance control, and easier to distinguish details. For the price that is. Beyond that, I would certainly say that warm and dark fans would likely not completely appreciate the amount of shimmer and sparkle up top. That all said, I think the treble is very nice. I don’t find the treble to be sibilant at all, it sparkles yet doesn’t pierce, it isn’t shouty or harsh and the note structure and body is well done in my opinion. Also, I will repeat what I said a moment ago, the treble really does fit the overall sound in a very coherent and nice way.

Technicalities​

Soundstage​

This one surprised me and I’m not sure why. I suppose I was awaiting the dreaded flat plain of sound that I always hear on planar magnetic sets. Of course, I’ve had quite a few where they had some depth and 3d qualities so… I don’t know why I worried. The stage size of the S15 is good for what it is. I hear a pretty wide stage with decent height (maybe average) and I hear nice depth to the sound. There is a 3D element to my music which adds a somewhat holographic sound field within my mindscape, in a way that sounds realistic. Some tracks it does feel like I’m in the room with the band. I wouldn’t call the stage some massive expanse of sound, but I do find it above average in size. Overall, the stage is a plus in my eyes. Let’s put it this way, there is most certainly nothing which seems cramped or congested … At all. There’s air and room to breathe folks.

Separation / Imaging​

Separation of elements within an imaginary stage have no issue sounding distinct and delineated to the extent that a track will allow. I think this is an area where the Letshuoer S15 excels which is usually a hallmark trait of planar magnetic earphones. Some do it better than others of course. The faster transient attack/decay, the clean notes and nice definition (albeit smooth), the space inside the stage to operate and the capability of the drivers all goes into how well the S15 is able to create space and separation. Imaging is another strong suit. So long as you aren’t listening to a bass heavy track. In those songs I did notice some blending happening. We have fantastic depth for layering of sounds which helps tremendously in how well I am able to place an instrument. Left to right is spot on as well. The S15 is good y’all.

Detail Retrieval ​

The Letshuoer S15 is a very capable iem friends and I think that detail retrieval is another area that the S15 will not dissatisfy those who enjoy a richer sound. Again, the sound is open enough, snappy enough, clean enough, and balanced just enough to afford the listener with some of the finer nuances within most tracks. Possibly on bass heavier songs with mid-bass boom overtaking the rest of the mix, that is a moment that you obviously won’t hear every last fine detail. Of course, nobody is listening for details on a bass heavy track, let’s just be real. However, in songs that most folks generally enjoy picking apart the subtleties in their music, I think you’ll be happy with the S15. Live tracks are phenomenal, and I do enjoy listening for finer details in the face of a warmer and more solid delivery.

Details cont…​

Now, is the S15 a detail monster? Um… No. No, I don’t think the main tuning strategy was to assure that the S15 would be a detail king. This set was tuned well with a nice mix of technical and musical and I’d say that Letshuoer absolutely nailed it. To me it’s much more-so on the musical and emotional side of the aisle. There are plenty of actual detail banger iems out there in the Audioverse and especially within the $300 to $400 price point. There are sets that specialize in this attribute and most of the time those sets will not carry this sense of musicality and macro-dynamic fullness. They are usually less musical, more analytical and drier sounding with an even better balance across the mix. I still maintain that the detail retrieval of the Letshuoer S15 is certainly a “Pro”, especially in the face of this tuning effort.

​

Comparisons​

Note: Due to the length of this review, I will keep all comparisons very general and more concise than usual. I will still do my best to help the reader understand what I believe the differences are so to help with understanding the set I’m reviewing. None of my comparisons are a duel to the death or a battle to find out which is better. That is pointless to me, and I don’t think it helps you to make a good decision. However, verbiage within the comparison may just make it easy to spot the better set.

Letshuoer S12 Pro ($159) ​

The Letshuoer S12 Pro (S12 Pro Review) is one of those sets that quite literally did almost everything right. For me anyways. The S12P (as I’ll call it) is a true banger of a set that was generally praised almost across the board. Truly a fantastic set which is still in the mouth of hobbyists. As it should be. The S12P also has a 14.8 mm planar magnetic driver and comes very well accessorized in a way that is fitting of its price. Truly a beauty of a set that is still one of the most gorgeous in its price point.

Differences
For starters, both sets are built differently. I have a sneaky suspicion that many folks would consider the S12P the better built set. The S12P’s built with an all-alloy build while the “HeyGears” resin build of the newer S15 is not quite as solid. I don’t necessarily think that though. The HeyGears build quality is phenomenal and won’t corrode and you won’t get scratches or scuff marks either. But still, if “durability” is what we deem the defining characteristic in “build quality” then, I’m sure many would consider the S12 Pro the better built set. I would also venture to say that most folks would crown the S12 Pro the better-looking set. I’m also not as convinced on that, but again, I’m sure many folks will see it that way. I actually like them both quite a lot. The S15 is a bit larger but I find them more comfortable as the material is just easier on the ears. Accessories are obviously much better in the S15 as well. Of course, the most important difference is that the newer S15 is roughly $180 more expensive.

Sound Differences​

I find the new S15 is a bit warmer whereas the S12P comes across slightly more vibrant up top. I find the S12P to be more V-shaped then the S15 as the S15 has a slightly better balance over the mix. Between the two I find the S15 has better note definition and better control over the mix. The S15 has much more of a thick and rich timbre that is better textured to the S12P’s leaner sound. Details emerge well on but the S12P does illuminate the minutiae a hair easier. Imaging is better on the S15, and the stage size is a bit larger too with better depth of field on the S15. The S15 simply has (in my opinion) the more engaging sound with thicker note weight across the board.

Bass Region​

The S12P and the S15 both have a healthy bass presence but the S15 simply has more control over the region. There’s a more round and warm depth with better texture. Not taking anything away from the S12P. The S15 has an easier time keeping up with quicker bass tracks and has a more solid density down low. I find the S15 to have a more robust and warm authority on attack whereas the S12P comes across thinner and less dynamic in comparison. That all said, the S12P has flatter slam and flatter boom with its increased quantity compared to the S15. You can hear pretty easily that the S12P has more sub-bass emphasis, but even with the emphasis the S15 has better tactile and palpable feel to the drone down low. The S12P has a more vibrant ADSR delivery with a flatter perceived presence. The S15 is simply fuller and more 3D in its attack presence. The S15 flat out has the more sophisticated and developed bass.

Midrange​

The S15 has a more forward midrange but also a more robust note weight while coming across smoother to my ears as well. Fans of a drier and leaner and more lustrous presentation may enjoy the S12P a bit more but for everyone else the S15 is absolutely engrossing in this area. The S15 does vocals with a silkier and inviting tonality and timbre and with a more 3D note delivery. Females aren’t as vibrant on the S15, but they are more luscious and charming to this guy. The S12P doesn’t have the body and 3D rendering and layering of the S15. The S12P has a brighter sound that adds that planar grain to the attack edge which the S15 does not have.

Treble​

I find both of these sets do the treble very well in their own way. I wouldn’t be surprised to find many folks digging the S12P’s treble a bit more as there is more clarity & brilliance up top. Again, the S15 has more note body and fullness with just enough bite and haptic recognition. The S15 has a lusher body and a more mellifluous sound altogether. Both sets have a decently extended treble but the S12P does define the finer details a pinch better. Of course, that’s at the expense of rich musicality.

My thoughts​

Guys and gals, what can I say? This may be an easy decision. The defining factor in all of this will affect almost everyone differently. That is… $180 more. That $180 speaks volumes. Now, I do feel that these two have enough tonal differences to warrant a “preference battle”, but in the end it’ll all come down to what you can afford. If you can plop the extra dough down on the S15 then it would be irresponsible for me not to tell you that “Yes, the S15 is the better iem”. In fact, without question the S15 is the better set in my mind. However, that’s just me. Just because it costs more doesn’t mean it’s better for everyone. If this was a preference battle for you and your preferences aligned closer to the S12P than… Easy decision. The one thing that is true about both however is that both sets are very good options where they are priced.

Hidizs MP145 (Now: $149 MSRP: $199)​

What a great set this is friends. I was absolutely taken aback by the Hidizs MP145 (MP145 Review) and how well it replayed my music for the price. This set is a stunning peice of art that is absolutely built like a tank. What Hidizs did with this set is nothing short of impressive. The MP145 has a 14.5 mm planar magnetic driver and a hulkingly large frame and chassis. Truly one of my favorite iems of 2023 folks. But does it do enough to warrant purchasing the S15 instead? Or does it make sense to upgrade to the S15?

Differences
For one, the MP145 is built to a champion level and seems to be built more durable. I don’t know if it’s as structurally sound as the S15, but it is built very well. Made with an all-alloy build and enormous in the ear, the MP145 is truly a uniquely designed iem and I guarantee you won’t purchase anything else quite like it. I like both designs and the aesthetic appeal of both iems but it’s hard to say the S15 looks better. Both sets are accessorized very well, but I’d give the nod to the S15 as that cable is great and it has a carrying case. Without question the S15 is the more comfortable set of the two as the MP145 is just very large and sometimes the cable slides off the ear. Though weight distribution is great. Of we are going by MSRP than the Letshuoer S15 is about $130 more in price, so obviously that is something to consider.

Sound Differences​

I find both sets offer a warmer delivery but the MP145 is a shade brighter. I find the timbre of the S15 has less of that planar timbre and a bit better note density. Both sets have a near 3D sound field but the S15 does give a rounder presentation, a more weighted presentation and a more holographic replay. The S15 has a more expressive macro-dynamic fullness with more dimension to the sound. The S15 is also a bit smoother in my opinion. Detail retrieval is actually a bit better on the MP145 but they both fare well there. I find imaging and placement of elements within a stage easier to spot on the S15. The soundstage is a bit more widespread on the MP145, but depth of field is better and more 3D on the S15.

Bass Region​

I find both sets have a nicely tuned low-end. Both sets can BANG friends! However, as far as actual quantity is concerned the S15 has a bit more with a more robust sound but both iems carry nice transient swiftness. The S15 has more of a solid note definition as the MP145 is a bit more pillowy at the note edge on attack. The MP145 sounds flatter in its note delivery to me with a drier tone, more paper to a degree. The S15 is more dense, secure, round in its presence and bolder in authority. They are simply different animals. Both are really great in my opinion, but both will appeal to a different audience.

Midrange​

The S15 has the milkier, smoother and thicker sound in this region while being more forward in the mix for both males and female vocalists. I love the MP145’s vocal delivery and really do prop it up at the price it is at but the S15 is simply more enthralling, more engaging, lusher, more 3D, and simply comes across a bit truer to life. Both are fantastic but the S15 is special here folks. The S15 is somehow warmer but also more sprightly, more lively, more dynamic. Details emerge good on both.

Treble Region​

The highs on the MP145 come across brighter with slightly better extension I to the highest of highs. The S15 has better definition in this region with better control. Better micro-dynamic agility and adds some extra bite and contour that the MP145 only slightly lacks in comparison.

My thoughts​

Another great set that is far cheaper than the Letshuoer S15. Perhaps these are horrible comparisons for this review. I figured anyone wanting a planar set may just want to read about other planars iems in the market. Maybe that wasn’t the best decision? There are very few planar sets in the same price point, and I can only compare what I have. Still, we find ourselves in the same predicament as the last comparison. The S15 is a lot more money. Yes, it is a better sounding set (to me) but is it that much better? Well, people will pay for incremental changes folks. That’s just a hard reality. This is a personal decision for all of you who are reading if these two are in front of you. Both are phenomenal at their price, and both make this reviewer very happy.

Raptgo Hook-X ($239)​

The next comparison is yet another planar magnetic earphone, the Raptgo Hook-X (Hook-X Review). The Hook-X is flat out one of the best sounding planars in the market. At least that my ears have heard. I have held this set on sort-of a “planar pedestal” to which my bar, or my personal standard would be set for this specific driver type. The Hook-X does have one more thing up its sleeve. Not only is it equipped with a 14.2 mm planar magnetic driver, but it’s also outfitted with an 18-layer double-sided Piezoelectric (PZT) driver. Truly this is a set which came out of nowhere and rightfully made huge waves throughout the hobby. Surely the Hook-X has been able to stay relevant as well as remain one of the best and most complete planar sets out there. Now, whether it stacks up to the Letshuoer S15 is another thing altogether.

Differences
Beginning with the build of each set; the Hook-X actually has an alloy shell and an open back plastic faceplate. Of course, we know the S15’s build by now. I think this is pretty much a draw in my mind. Both sets evoke feelings of durability and longevity, and each has a structurally sound chassis. As far as the look, again, I love these both. I couldn’t choose. Both look dope. Now, the Hook-X is a bit larger with a deeper and slightly wider shell, but I would say that the Hook-X does fit me a little better, though neither set is a bad fit. As far as accessories, the S15 is the better accessorized set of the two, but again, both are great unboxing experiences. I would say that the S15’s cable is better, more premium but both are great modular cables.

Sound Differences​

Between the two the Letshuoer S15 has the slightly warmer sound yet never really strays from that warm/neutral sound. The Hook-X has some bright spots likely brought on by the PZT driver which handles the high-highs. I find the S15 has a smoother delivery with better clarity and control. Please understand that this is very minimal. I just find the S15 has a bit better control over the mix with a more contoured playback that defines notes a bit better. Not only defines them but seems to handle micro-dynamics or transients a bit better. The notes are more round and complete to me. Both sets have a more expressive macro-dynamic sound but the S15 sounds fuller and more buoyant. Both sets perform detail retrieval very well. Possibly (this is certainly debatable) the Hook-X draws out the finer stuff a bit better in the treble region while the S15 sounds more resolute in the midrange. Imaging is great on both sets, but the soundstage has more depth on the S15. Not that the Hook-X lacks but the sound field is more out in front and wide, it’s big but sprawled out in front. The S15 is all around.

Bass Region​

The bass on both sets is pretty similar in quantity except I notice that the Hook-X has some additional resonances at times while the S15 keeps tighter reins on its bass region. Both sets are very dynamic in this region, and both can entertain faster bass tracks with no problems. Truly both sound great down low with the type of bass that will be what a track asks it to be. Maybe the S15’s bass sounds a hint more forward as the Hook-X has some extra treble emphasis to sort of counter its low-end to a degree. After listening to about 10 bass tracks, I feel the S15 has a slightly more polished bass. Again, I am very happy with both as the differences are marginal at best.

Midrange​

Beginning with male vocalists I find the Letshuoer S15 carries thicker note weight and once again has a fuller and more natural sound. I hear the Hook-X has a more forward sound which can be a bit too lustery and grainy in some situations. Especially with males that perform at a higher pitch. Lower register males have a stouter sound on the S15 with a rounder and more complete sound. Females pretty much follow suit. In the Hook-X they sound generally brighter, drier, shimmery, but really do sound nice for what it is. The S15 on the other hand has some semblance of shimmer but it’s kept in check while holding onto that note body and note roundness. The S15 has such a naturally holographic and well-tuned sound which separates all sounds and has smoother but more contoured vocals and instruments. The Hook-X simply comes across brighter yet has less dynamic energy. It also is subject to minor sibilance whereas on the S15 that is nowhere to be found.

Treble Region​

The treble of the Hook-X sounds brighter, more brilliant, maybe the emphasis adds some details that are easier to pick up on the Hook-X, but I echo this entire review; the S15 has better body! This is huge! The musicality aspect is so easily discernible friends. The Hook-X has a bit more treble bite as well and does have better treble extension up top but the S15 sounds less splashy with a more robust vibrance. Without question, clarity is better on the Hook-X in this region as it simply is boosted enough to cater to it. It’s drier and separated better in this region. Attack bite on the Hook-X is sharper, albeit thinner and brighter. I certainly enjoy the S15 more in this area as it is much less offensive. The Hook-X treble rise does affect the midrange snappiness and attack edge for percussion and detail retrieval is better on the Hook-X up top. However, I adore the sound of the S15, and I’d take it’s lush, smooth, and bodied sound any day.

My thoughts​

I realize this comparison doesn’t exactly sound like a ringing endorsement of the Raptgo Hook-X. However, it is a great set, truly. It has a slight bit more brilliant treble energy and can be a hair peakier, but it holds its own against any planar. Still, the S15 is a different beast folks. It is simply better in my opinion as it has the more controlled, and holographic replay with more of a musically toned sound. It also has better and more full note weight, but resolution may go to the Hook-X. Of course, there is a substantial price difference once again to be mindful of. Both are truly great sets for most any collection. Unless of course neither of them sounds like your preference.

​

Is it worth the asking price​

This is the big question from so many. They want to know, is the S15 really worth such a huge price jump? I read quite a bit of outrage over the pricing of this set. Is the S15 even worth this huge price jump from other planar iems? Let me start by saying, maybe. Like I said before, it all comes down to your “own” wallet & your “own” preferences. The truth is, you’re asking a question that I or any other reviewer can’t answer. How am I to know if the S15 will be worth the $200 more to “you” and for “you” than let’s say… The S12? It’s a ridiculous thing to ask really. I read on some forums, in Facebook etc. many comments revolving around “Is the S15 really $200 better?” What!?

Listen folks, I’m not in the game of telling you what’s the worth of anything… for you. You decide. There is no quantifiable way on planet earth to distinguish if anything is worthy of its price better than how it makes you personally feel. I’m not doing that for you. Letshuoer can ask whatever they want folks. They could’ve asked any amount for this set but they felt $330 was the amount that was reasonable for all the hard work they put into it. I get it though. It’s more than you are used to seeing. Well friends, until you put them (S15) in your ears, you won’t know. Until you sit and digest this set for multiple hours, you won’t know. Plain and simple. The best I can do is answer this question “for me”.

Is it worth it to me?​

Now, do I think the S15 is that much “better” than the other planars I’ve heard? 100% yes. Folks, the difference is substantial, and I do think it is worth the price. But please hear me… I’m not you. I’ve never heard a planar like this actually, and to be honest, it’s one of my favorites. I’m so used to a dryer, thinner, snappier and more artificial sound that when I heard this vocal friendly, 3D & lusher S15 sound… I couldn’t put them down. Truly they are the best planar magnetic earphone I’ve ever heard. Of course they also jive with what I personally prefer. Also, I wasn’t as impressed by the S12 or a handful of others for that matter. They all sound somewhat the same. Impressive sure, but simply different variations of similar tunings. This is different.

The Why​

Why? Where to start? Let’s begin with the packaging. The unboxing experience is absolutely at the $330 level in my opinion. Of course, not many people really care about this aspect but for those who do, just know it is a nice experience. The S15 comes with a great modular cable, actual good tips which makes sense for the set I’m reviewing. Which is a rarity. The threaded case isn’t bad, and you even get a poster friends! Next, the build is one of those dope HeyGears types with the softer feeling resin with the matte appearance. I loved it on the DZ4, and I love it on this set. The design language is what I would call sleek and modern with a minimalist approach. Very nice. However, it’s always about the sound and always will be. Forever the sound will be at least 80-90% of the true worth of an earphone.

Why cont…​

The sound is a beautiful rendition of a lush sound yet has a technically sufficient fine tuning and a boldly dynamic foundation which has a 3D holographic and totally immersive quality to it. Friends, it’s special. Now, there are sets out there with different driver configurations that do well against it in this price point. However, this one is very special. You have the transient quick sound which is agile enough to duck and dive around quick and complicated passages of music, but you also have that pervasive smoothness that isn’t simply a one noted affair. Instead that rich delivery has a personality; there’s roundness and a three dimensional, stereoscopic and robust sculpting of each and every note and there’s fantastic cohesion in the mix. Are there subjective issues? You betcha! Not everyone will jive with the Letshuoer S15 like I have. So many folks are in a different place in their audio journey and so many will not appreciate all that I’ve tried to describe. To me the Letshuoer S15 is not just a great planar earphone… no sir. To me the Letshuoer S15 is simply a great earphone in general. Yes, it is worth the $330 Letshuoer is asking for.

​

Conclusion​

To conclude my full written review of the Letshuoer S15 I have to thank the great people of Letshuoer for providing this set for a fair and honest review as well as a feature at Mobileaudiophile.com. I also want to thank you (the reader) for taking the time to actually read my thoughts and I do hope that it has helped you. You are why I do these reviews friends. I’ve been a hobbyist longer than I’ve been a reviewer and I know what it’s like to constantly search and seek out opinions. So, I hope I was in depth enough and I hope I’ve answered any questions you may have.

Different perspectives​

One thing I implore out of all of you is to seek out other perspectives about the Letshuoer S15. Friends, this set is great but don’t just take it from me. It may not be great at all to the next man. Take in other thoughts and opinions so that you can get a better idea of what the S15 sounds like and if it’ll fit your own personal preference. It’ll only help. We simply aren’t all the same and each of us has been down a different journey in audio, we’ve got different gear, different libraries of music, different hearing abilities and we don’t all have the same likes and dislikes. So please, don’t simply stop at me, check out some of the other reviewers out there who pour their time into their reviews. Please take good care, stay as safe as you are able and always… God Bless!



Full written review

General/Packaging/Build/Comfort
Letshuoer is a company that was founded in August 2016.They are specialised in making in ear monitors for stage use but they do have in ear monitors for audiophiles as well. They were called Shuoer previously and most of those who were in the community for a little while should be aware of it.
Today I have with me the S15, which is the upgrade and revision to the original S12. The S12 was very well received and they even have a S12 Pro iteration and also a collaboration with Z Reviews.
The packaging is minimal, but the overall design does look premium.
You will find two types of ear tips in the box, wide bore and narrow bore. The cable is silver plated monocrystalline copper cable in modular form, plugs provided are 4.4, 3.5 and 2.5mm. I am really surprised to see such high quality stock cable at this price point. The included 3D printed storage case looks premium as well. A very good unboxing experience overall.
The whole iem is smooth and there aren't any sharp edges. In terms of comfort,S15 fits very well in my ears and I have no discomfort even wearing them for long listening sessions,do take into consideration that everyone’s ear is different and if it fits well for me doesn’t mean it will fit well for you,but fortunately, Letshuoer does throw in plenty of ear tips choices,so i’m sure there will be one that fits eventually.

Gears used for this review

• Earmen Colibri
• Earmen Tradutto -> Earmen CH-Amp
• Fosi Audio DS1
• Hiby R6 II
• Letshuoer S15 Stock Cable and Eartips

Foreword
My review is solely based on what I hear via my equipment and I never consider my reviews to be objective in any way rather a subjective approach. Do take into consideration that everyone’s ear anatomy is not the same, so the psychoacoustics perception might be different as well, but i believe it will not stray too far



Sound
S15 is slightly warm sounding to my ears, a departure from the S12 which is bright and energetic. The tonality of the S15 is quite good for a planar, the planar timbre is very minimal, in fact you have to try very hard in order to spot it. Well done!

Bass

• The bass rendition is nowhere near basshead level but it certainly provides enough "fun"
• Bass extension is good and the sub bass rumble can be felt, definitely no slouch when it comes to EDM
• Bass has good texture and note weight to it,it is also tight and clean
• Mid bass has got thump to it and the transition between the sub and mid bass is quite balanced without sounding incoherent
• I personally find the tuning of bass is done right to my preference,somewhere between fun and audiophile but not venturing into the basshead category

Mids

• Timbre sounds correct to me and the midrange is actually quite lush
• Vocal doesn’t sound recessed, both male and female vocal has good texture to them,doesn’t sound thin at all
• Bass doesn’t bleed into the mids
• In general,i find that the mids are smooth from the lower mids to upper mids,on certain track where i listened with some IEM,the upper mids can be a little hot,but this is not the case with S15

Treble

• The treble is smooth, it has enough energy but not to the point where it is harsh and sibilant
• Detail retrieval is average for the asking, can be better in my opinion, but due to the nature of the tuning, i can see why it is in such way
• But to put it as a whole, the bass, mids and treble all together, perhaps this is how and why it sounded quite natural overall

Soundstage/Imaging

• S15’s soundstage sounds slightly out of head and quite open,but a little lacking in depth to give the perception of big soundstage,but overall it is quite good
• Imaging is good,the instruments can be pinpointed easily in busy track like Slipknot’s Duality

Driveability

• S15 is very easy to drive and it does sound decently loud even from weaker source like Apple’s Lightning Dongle
• Switching over to Earmen’s stack ,with decent driving power,bass seems to tighten up a little and better control is exhibited, in a way, it is quite scalable with power as well as source

Comparison (7Hz Timeless x AE)

• Switching over to Timeless x AE for the purpose of comparison,i would say the tonality between Timeless AE and S15 is slightly similar
• Bass on the Timeless AE is faster and lesser in terms of quantity, sub bass does rumble but a little rolled off
• Soundstage is slightly smaller and more in your head for Timeless AE
• Imaging both are on par
• Mids are a little thinner on the Timeless AE
• Treble is slightly more energetic compared to S15
• The shell of Timeless AE might be a little big for some

Final Thoughts
Having tested several planars from different brands, it’s safe to say S15 is my favourite at the moment, the incorporated R-Sonic PFM seamlessly with the DD to offer a natural sounding tuning yet retaining the planar’s characteristics such as the speed and technicalities. Although not the best when it comes to the technicalities, it is certainly a pair of very enjoyable sets of IEM. I have tried gaming, watching some videos with it, and it handled all of it with ease, positional audio in gaming, explosions from the games and movies, easily handled. Do I recommend this? Yes certainly!



*The S15 is sent over by Letshuoer for the purpose of this review. I thank them for the support and opportunity as always

Head over to the official store if you are interested in getting one, it is currently being priced at 329$:
Letshuoer S15 - Non affiliated

If you would like to know more about how the R-Sonic PFM works, head over to the following thread in Head-Fi:
R-Sonic PFM (Passive Filtering Module)

"In music the passions enjoy themselves"

~~Friedrich Nietzsche, German philosopher and philologist, author of The Birth Of Tragedy, The Gay Science and Beyond Good and Evil.


As the second phase of the battle of the planars still going on and many new entrants are trying hard to win some hearts and ears of the audio enthusiasts, LETSHUOER is one of the most active and resilient audio companies out there and they are now acclaimed as the veterans of this particular competition of planar sets in the audio market. With the release of S12 regular and S12 PRO in the first phase battle of the planar sets, they were able to gain and manage to hold a substantial ground in the audio market up to this day that makes these products as one of the most successful planar IEMs in the audio enthusiast sphere.



And now, LETSHUOER release a successor model and they add some interesting features on it, knowing the core philosophy of their company, they are striving for innovation and improvement on their every product releases.



This is LETSHUOER S15, one of the latest IEMs with a planar magnetic driver in the audio market. According to LETSHUOER, this set uses a 3rd generation of planar magnetic driver and it shares similar size with the previous generation of the said type of driver which are measured at 14.8mm diameter. Aside from the latest generation of planar magnetic driver, they also implemented a new technology on this one, the 6mm R-sonic Passive Filtering Module which supports the performance of the planar magnetic driver. The R-sonic Passive Filtering Mode isn't a typical passive radiator as its working principle is quite a contrast in technical sense. It employs a membrane that functions as a filter that corresponds with the amount of pressure inside our ear canal to make it more comfortable for long listening sessons and less ear fatigue due to a reduced pneumatic pressure generated from the drivers. The module itself is quite adaptable as it has a semi-opened chamber that works in tandem with vent ports on its shells as it able to adjust itself from the volume output of sound pressure level, either it is in active or in idling mode. Thus, this system will also help the longevity of the active driver by minimising the possibility of wear and tear through lessening the constant movements of its diaphragm as planar magnetics are known to be very sensitive. For more technical details about this technology, just click here.



One of the benefits of this technology on its overall sound quality is to deliver a more resonant effect and at the same time, a deeper, richer and even darker tone on the lower octaves notes on vocals and instruments with a noticeable improvement of some of its technical aspect. Another implementation that LETSHUOER putting on this set is the dual acoustic with filter crossover for smoother transition of its frequencies for better balance sound.



The driver along with its proprietary components were encased in a composite shell chassis. The cavity base part of the shell is a medical-grade resin that was moulded via 3D-printing process done by HEYGEARS while its faceplate is a CNC-milled aluminium alloy that underwent a sand-blasting process to give that matte-finished surface. The contours of its shells are oval-shaped and they are medium-sized. There are two vent holes on its cavity base that will serve as an exhaust for excess air pressure from its acoustic chamber that was generated from the fast and uniform motion of planar magnetics. The overall design aesthetics of its shells is quite unusual as its faceplate has some angular and sharp patterns that reminds me of a claw of a raptor or a fang of a snake. Like all of their previous products, LETSHUOER continues to use a proven 0.78mm 2-pin connector for this set.



When it comes to wearing, The S15 is quite comfortable as it rests well into my lugholes with any issues at all. It has an excellent passive noise isolation as it manages to block some unwarranted noises coming from the outside surroundings.



In regards of its stock cable, The cable is of a high quality and it is also fairly thick with its braided 2-core monocrystalline silver-plated copper. This cable is also a modular one as we can interchanged its termination plug for different types of audio jack interface. There are 3 types of termination plugs we could choose from, either its a 3.5mm SE, a 2.5mm balanced or 4.4mm balanced, all options are available for its intended usage.



The packaging box of LETSHUOER S15 is quite large and how it was presented inside during the unboxing phase is remarkable as the inclusions are well-organised and the majority of the contents are in a drawer compartment.



Here are the following contents inside of LETSHUOER S15's box:

■ Pair of LETSHUOER S15 IEM transducers

■ Stock cable

■ 3.5mm, 2.5mm and 4.4mm termination plugs

■ Circular IEM storage case with rubber-like coating

■ Three (3) balanced ear tips in different standard sizes.

■ Three (3) vocal ear tips in different standard sizes.

■ Paperwork like instruction manual, warranty card and Q.C. stub.



Regarding its amplification and power scaling, S15 can be driven by sources with decent power output like smartphones or tablets but we will definitely noticed its lack of dynamics and snappiness on its overall frequency range. Amplify it with proper power output and this set will give a fullest range of its sound with a vivid quality on it.



As for its profile on its tonality, LETSHUOER S15 has a mild U-shaped sound signature with an accent of warmish-balanced tonality on it. It has a slight emphasis on low and some parts of high frequencies while maintaining a well-balanced midrange.


(The graph was provided by @baskingshark , thanks to his effort for measuring this set)




LOWS/BASS:

For a planar set, the bass quality of the S15 is quite impressive and with the implementation of R-sonic Passive Filtering Module does even further improve its bass definition that a very few planar sets are able to match its performance. The bass response of this set is indeed punchy, precise and snappy with good control and maintain a clean sound.

Both sub-bass and mid-bass are equally laid-out in the low frequency range to give a well-balanced sound while having an authoritative bass quality. There's a discernible sub-bass rumble and reverberations coming from certain instruments like low tone bass guitars, drum machines, synthesisers and octabasses. Mid-bass have suitable texture to give a more well-bodied sound on instruments and vocals. Bass guitars sound broad and resonant while cellos have warm, full and stately sound on them. Bass kick drums have sonorous, thudding and rumbling sound and it is capable of delineating the tones of fast double bass of some extreme metal tracks. Bass-baritone vocals sounds well-rendered on this one as they have these deep, resonant and rumbling voices to give that dense and wool-like sound.


MIDRANGE:

The midrange presentation of this set is noticeable a tad indented in the overall frequency range spectrum but it still maintains a well-balanced and fairly textured to project vocals and instruments in a most natural and tonally accurate manner.

Both vocals, either male or female are well-bodied and eloquently presented, as male vocals are well-modulated while female vocals have luscious and euphonic sound of them with sufficient energy on them. On baritones, the lighter ones like light baritone and lyric baritone have a mellow, sweet and smooth sound, while deeper ones like kavalier baritone, Verdi baritone and dramatic baritone have steely, richer and warmer sound respectively. Tenors vocals whether its a leggero, lyric, spinto, dramatic and even a rarer type one, the heldentenors have agile, bright, dazzling, ringing and emotive sound on them. Countertenors too have a graceful, warm and tender sound on them as I was able to enjoy listening to their falsetto voices on hitting their highest note. And then on female vocals, contraltos are able to project their distinctive vocals which sound smoky, husky and rich, while mezzo-sopranos have a musky, fiery and sensitive sound on either lyric or dramatic type. And then sopranos, this set is capable to deliver their typical sound characteristics like coloratura sopranos have a bright and tangy sound of their high velocity vocal passage while soubrette and lyric soprano vocals have bright timbre with added sweet and a hint of rich sound, and then dramatic sopranos have richer and deep resonant emotive vocals on them.

As for instruments, on string ones like guitars and violins, guitars have a balanced and fundamental sound with added articulation and crispness on them, and violins have lively, vibrant and eloquent sound on every grip and stroke in its bow strings. Then on brasses, trumpets have substantial, full and vivid sound while trombones have tense, brassy and powerful sound, and then horns have warm, resounding and intense sound on them. Woodwinds like concert flutes, piccolos, clarinets and saxophones, flutes have silvery, rich and mellow sound, piccolos have a clear and intense sound on them while clarinets have its velvety and warm sound, then on saxophones have a reedy and sombre sound on them. On percussive instruments, snare have precise, hard and bright sound, field drums have dark, sombre and full sound on every stroke, tom-toms have a warm, rumbling and orotund sound on them, and kettledrums have heavy, deep and resonant sound on them. Pianos seem to have warm, full-bodied sound while maintaining a well-balanced tone on them.


HIGHS/TREBLE:

For those who are quite familiar with the typical planar sound on the treble register, this set's treble quality is quite different compared to its peers. It manages to tame down and control those too energetic, prickly and sizzle sound that we usually encounter on planar magnetics whether it's an IEM or headphones. Therefore, the overall treble response of S15 is smooth and well-balanced while having a properly quantifying sparkle and good airy extension. In my hearing, there's an observable highlight on the upper mids and presence part that gives a well-executed percussive and rhythm instrument attack and an emphasis of projecting vocal articulation. The accented presence gives some crisper, detail and clarity of sound.

As for instruments, cymbals have a bright, shimmer and resonant sound while hi-hats have a shortened buzzing sound on them. Glockenspiels have brilliant and lustrous sound and celestas have silvery and sweet sound that gives those heavenly or aristocratic ball court vibe on their distinctive monotone sound.


SOUNDSTAGE, IMAGING AND OTHER TECHNICALITIES:

Given that this is a planar set, it will have an excellent technical capabilities and S15 did inherent those qualities. It has a quite spacious sound/speaker stage as it has a fairly wide span from left to right, good height ceiling and impressive depth distance between front to rear that within my headroom, it gives me an impression of roomy and sizable auditory spatiality. This gives me an excellent head shadow on how I perceived it.

Stereo imaging projects an atmospheric and 3D-like presentation where I was able to locate the placement of instruments and vocals, and all of its elements are well-separated with considerable gaps and spacing on each other while it was placed in well-defined and precise layering of tones and frequencies in a black background of its sonic canvas. This incredible aspect will let you enjoy listening to some of the most complex multi-instrument tracks like jazz, movies scores and orchestras that you definitely hear a clean, articulate and well-furnish sound.

Coherency on this one is on a excellent mark as planar magnetic drivers are known for its precise, fast transient response and well-handle decay and this set have those qualities at all. Resolution capability on this is one is quite remarkable as it has a solid fundamental on macro-dynamics while having a clear, sharp definition on its micro-detail retrieval as it was able to extract some nuances and detail infos like note ends and notation attacks from an audio track.


PEER COMPARISONS:

LETSHUOER S12 PRO

■ This is S15's supposedly predecessor but it is way much cheaper, it uses the same diameter size of planar magnetic and it was encapsulated in an all metal alloy shell. Like all LETSHUOER products, it has a good amount of accesories and it also has a modular cable.

■ Tonality-wise, S12 PRO has a bright U-shaped sound profile which makes it tonally contrasting to S15's. It has a tighter bass response with less textured mid-bass, a more noticeable notched midrange but it sounds more transparent, crisper, a bit more energetic sound particularly on high octave female vocals and instruments like strings and woodwinds. And brighter and shimmering treble response with some occurrences of sibilance. In technicalities, S12 PRO sound/speaker stage size is more of an above average when it compares to S15 which has a bit wider sound field and has a less solid note on macro-dynamics, the rest of technical aspects are very similar after all.


AUDEZE iSINE 10 (Demo)

■ This is probably the first planar magnetic IEM from AUDEZE and it has an unusual shell chassis design that reminds me of a spaceship. It has a semi-open back design and it houses a larger 30mm first generation planar magnetic driver. To be honest, when I tested this one a few years ago, I've struggling to get a better fitting of it.

■ iSINE 10 is definitely a V-shaped sounding IEM as I vividly remember how it sounds. Compared to S15, It has a tight and hollow bass response, a very recessed and lean midrange that also give some odd timbre and tonality on vocals and instruments, particularly female vocals and some percussives, and harsh and peaky treble response that might be a problematic to treble-sensitives. Technicalities-wise, due to its semi-open back design, its projects a wider soundstage compare to S15 and it also has a good stereo imaging, separation and resolution capabilities but power scaling on this one absolutely nightmare on this one as this is definitely hard to drive that you need a desktop-grade DAC/amp amplifier just to drive this set properly.


AUDEZE iSINE 20 (Demo)

■ This was the most pricey planar magnetic IEM that I've tested so far, it still follows the design philosophy of its predecessor, The iSINE 20 also employs a 30mm planar magnetic driver and like the iSINE 10, I'm also struggling to find a better fitting on this one.

■ iSINE 20 is still a V-shaped sounding one but compared to iSINE 10, it is a bit more refined. It is a sub-bass focus bass response and bit lean mid-bass, a recessed midrange but at least it has bit warm to have a semblance of an ample texture and density on its note weight but there some instances that its timbre and tonality sounds really odd to my ears especially to female vocals sounds too shouty or a bit nasally and too much ceiling and lingering sound on acoustic guitars and somehow a smooth treble response that it dulls the shimmer and crispness on it and even subdues the airy extension. The technical performance of this set is somehow excellent just like its predecessor but I also noticed its less sharp definition of its micro-dynamics resolution. This set is also hard to drive too like the iSINE 10's so the best option is to use the Cipher cable for its built-in DSP decoder but it is specifically built for iPhones with lightning port and I don't like iPhones personally.


To summarise my review on this device, LETSHUOER S15 is indeed an upgrade from the previous S12 in terms of tonality and some technical capabilities. It really differentiates itself from its predecessors like implementation of new technology and different design aesthetics which is beneficial for better sound quality, more tonal balance and better fitting ergonomics.

As I end my assessment of this, here are some questions that really float in my thoughts. To whom is this IEM for? Is the price hike from the previous model is justified? Why did it decide to ditch an all metal shell design and choosing a composite shell one?

Here are some logical answers that I can share, the first one is if you look for a well-balanced sounding set with excellent technical capabilities, good resolution capabilities with a bit fun, engaging and enjoyable sound factor, LETSHUOER S15 is the set you are looking for. Second one is the increase of its price, With a working proprietary audio technologies that LETSHUOER developed and were implemented inside of the S15 and a bit better modular stock cable, its asking price is somehow justified in my opinion given my exposure of some older planar IEM models that were even more expensive but its tuning is quite atrocious, and last but not the least, LETSHUOER seems aware on some reported condensation issues on all-metal shell IEMs especially if you live in a temperate locality and using a newer composite shell design will minimise those issues at all.

I hope that you really enjoy reading my review on this set.

LETSHUOER S15 is now available at LETSHUOER'S official store. You can check the unaffliated link that I've provided below:

★★LETSHUOER S15 - OFFICIAL STORE★★

Here are my previous reviews on other LETSHUOER products:


◆ LETSHUOER GALILEO (First impressions)

◆ LETSHUOER CADENZA 12

◆ LETSHUOER EJ09

◆ LETSHUOER CONDUCTOR (First impressions)

◆ LETSHUOER D13

◆ LETSHUOER S12 PRO

◆ LETSHUOER EJ07M

◆ LETSHUOER DZ4





SPECIFICATION:

MODEL: LETSHUOER S15
IMPEDANCE: 30Ω
SENSITIVITY: 106dB
FREQUENCY RESPONSE: 20Hz – 40KHz
CABLE LENGTH: 1.2M
PIN TYPE: 2-PIN CONNECTOR
PLUG TYPE: 3.5mm, 2.5mm. 4.4mm
DRIVER UNIT(S): (1) PLANAR DYNAMIC DRIVER + (1) PASSIVE FILTERING MODULE

Some Tracks Tested: ( * = 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 LETSHUOER 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 IVY GAO for providing this review unit. I truly appreciate their generosity and trust towards me and other reviewers.

TLDR:

The Letshuoer S15 is an extraordinary in-ear headphone that offers an immersive audio experience. Its soundstage is wide and captures both the grand dynamics and intricate details of each instrument. The vocals are solid and robust, adding depth to the audio experience, particularly during powerful guitar and drum sections.

The S15 package comes with the product images.



Sound impression:



I had my first hands-on experience with the LCD-i4, which was an excellent IEM with its flaws and was not cheap. Later on, Unique Melody released ME1, which looked more like an Audeze IEM than anything. I bought one, and I had no regrets until I listened to it. It is the worst-sounding IEM I've ever tried. I hated the sound so much that I couldn't justify selling it, and I ended up giving it away. I then thought that the planar IEM format would be more possible to produce cheaply and get it wrong. However, the S15 proved me wrong!

The S15's bass performance is outstanding, providing a dynamic range that transitions smoothly from thumpy to punchy. The 14.8mm planar magnetic driver contributes to a strong bass response, avoiding overpowering vibrations while maintaining a substantial and impactful presence. This controlled bass quality enhances the overall fun factor when one listens to such a bass type. S15 is able to maintain such bass quality without compromising on the richness of the rest of the frequencies too much.

The S15 mid-bass is visceral, making it amazing for EDM and dance music. However, it has a strong personality that can cause a bias towards it. The S15's versatility across genres makes it suitable for a wide range of musical preferences.

While reading my impressions above, one might think that the S15 has a natural bass boast. That, was not my intention. The S15 does not have a bass boast bias, but it does let mid-bass hit shine more, should the track have a midbass focus.

I recently reviewed Spirit Torinio Twin pulsar, and to my ears, that IEM has a more detailed, tactile bass, but if my sources are right, the S15 is half the cost of that IEM. While the S15 might have less quality bass portrayal, it has a much better natural soundstage than Twin Pulse. While sound still feels within your head, instrument placement is easier to pinpoint than Twin-pulse.

The Letshuoer S15 is a closed-form IEM that is affordable. If it had been released 5 years ago or by another brand, it would have been placed easily within the 1-1.5K price bracket. It offers dynamic sound performance, showcasing technical excellence in bass, midrange, and treble frequencies. Its well-rounded sound profile positions it as a noteworthy contender in the sub $1000 bracket. Its build quality outshines some flagship IEMs I've tried this year. It is designed to be engaging, durable, and something one would use day to day without breaking the bank.

Source matching:

Oddly enough, I did not sense playing S15 from a higher-end source adding more refinement to S15. I enjoy the tonality of the RS6 S15 as much as I did with the N8ii and the Lotoo PAW S1.
I did enjoy pairing it with RS6 as I felt it added richness to the midrange.

Conclusion:

In conclusion, the Letshuoer S15 is an excellent choice for engaging, durable, and affordable in-ear headphones. Its well-rounded sound profile, technical excellence, and build quality make it a noteworthy contender in the sub $1000 bracket. It is perfect for daily use, providing a passive way to remove as much of the external world as possible and enjoy your favourite music on your daily commute.

Letshuoer seems to be on the right path, and I haven’t come across any product they made that sounded bad. I feel S15 can be further refined and worked on. I personally love to see a flagship planar version of the S15, with better management, a thinner membrane, and perhaps a less resonance metallic housing.

First of all, I would like to thank Letshuoer for providing me with the new S15 for a review before its release (planned release is December 2023). Since I have already taken a close look at Letshuoer's top model, the Cadenza 12, I can compare the two models very well. With the S12, Letshuoer has already released the company's first planar magnetic IEM and has received a lot of praise for it. With the S15, this technology has now been taken to new heights with the installation of a passive filtering module for the first time. In addition to achieving a higher sound pressure level by increasing the excursion of the driver, this also improves distortion. Letshuoer is talking about an S15 that is no longer comparable to an S12, but has been improved in all respects. This is (unfortunately) also reflected in the price. The S15 costs around 329 USD compared to 150 US for the S12. I will analyze whether the S15 is worth the money later on.




The supplied connection cable is surprisingly good in this price range. This is a 216-core silver-plated copper cable. It is elegantly finished and very soft and light. The highlight of the whole thing is that in addition to the cable, three interchangeable plugs (3.5mm, 2.5mm and 4.4mm) are also supplied so that the S15 can be used with all possible sources. This is something I would like to see from every manufacturer in the future!

The S15 itself is solidly finished in a light blue shell with a silver faceplate. Of course, you won't find a reflective titanium housing like the Cadenza 12 or an elaborately designed storage box here. But I wouldn't expect that in the USD 329 price range, because the Cadenza 12 costs USD 2000!







By using a single driver, the housing is nice and light and the S15 sits ultra-comfortably in my ears. The fact that I almost exclusively own IEMs with umpteen drivers makes the difference to the S15 very clear. The price you pay for multiple drivers always comes with the weight, size and comfort. The S15 is like balm in the ears and can hardly be felt. Two different silicone tips are supplied, known as "Vocal ear tips" and "Balanced ear tips". The former emphasize the mids somewhat. As I have an extensive collection of ear tips myself, after a few trials I decided on the Azla Clear, which I found to be the most balanced sounding with the S15 and also very comfortable.

In addition to the cable, the adapters and the IEMs, the box also contains a round metal box and instructions. For the sound test, I use my iBasso DX320 MAX Ti to which I connect the S15 via a 4.4 mm plug. The S15 is a little harder to drive than BA or DD IEMs, so I occasionally switch to the 2nd gain stage depending on the recording. One thing up front: the S15 is really very level stable and can effortlessly reproduce very high volumes.




Until now, I only knew of one IEM with a planar magnetic driver, namely the Audeze Euclid. However, this much more expensive IEM cannot compete with the S15 in terms of coherence. In my opinion, the Letshuoer is much better tuned over the entire frequency range and technically on a par with the Audeze. So how does it sound? Compared to the Cadenza 12, the S15 is slightly boosted in the upper mid-range and has softer highs. Overall, this results in a warmer sound with a bass range that is roughly on a par with the Cadenza 12 in terms of quantity.

The highlight of the S15 is certainly the bass range. The character of the planar magnetic driver can be heard directly. It sounds different to a BA or DD bass. It's just like comparing the bass of a Focal Utopia with that of an Audeze LCD-5. The planar magnetic driver sounds fuller, especially in the low bass range, and doesn't drop down into the deepest cellar, which leads to a tremendous audibility of the entire bass range and is also very level stable. With the S15, it's not just the bass quality that impresses, but also the fullness and kick bass that is never too little, even with modern genres such as rock, pop, metal and EDM. I would say that even bassheads will enjoy this type of bass reproduction. BA drivers for the bass range still sound a touch faster, DD drivers provide the better visceral impact. I think planar magnetic drivers are somewhere in between and combine both characteristics if they are well implemented. I wasn't blown away by the bass range of the Euclid. I am delighted with the S15!

How does it look in the other areas? Thanks to the slightly warmer, smoother tuning, even the brightest recordings I own never lead to sibilance. Where I can almost sense the sibilance in the Cadenza 12, I never have that feeling with the S15. It also makes poorer material sound quite acceptable and doesn't immediately reveal everything. The resolution is good, but can't quite keep up with a Cadenza 12 or a U4s.

The stage presentation is rather intimate and not as expansive as with the Cadenza 12, but the very good separation and fast reproduction of transients ensure that the instruments have enough air and distance between them. Overall, it doesn't sound too warm but also not as airy as a Radon6, which is also one of the best IEMs in the world in this discipline.

The S15 is an IEM that cuts a fine figure across all genres and is ideal for simply unwinding after a hard day's work and enjoying a pleasant carpet of sound. The S15 invites you to take a relaxing journey into your own music collection and after a short time you forget that you have an IEM in your ear, because the comfort is really top class!

I think Letshuoer has achieved a great success with the S15 in the form of a planar magnetic driver. I haven't heard a better one myself, but I have to say that I only know the Audeze Euclid. What you can say for sure is that there is not much in the USD 400 range that can hold a candle to the S15. Because it easily outperforms higher-priced models. If you like a warmer and smoother reproduction, I can warmly recommend that you consider the S15. It is not really suitable for audiophiles looking for a magnifying glass of sound. For this, Letshuoer has the Cadenza 12 model in it