Letshuoer S15 – An Essential Planar Upgrade (Pavan’s take)

Letshuoer S15 – An Essential Planar Upgrade (Pavan’s take)

Introduction

Hello everyone. Today I am writing about the S15 which is the latest from Letshuoer. I came to know about the Letshuoer brand through their legendary S12 planar magnetic IEM which happened to be my first planar IEM purchase as well. I still consider them legendary to this date. And I am thankful to Letshuoer for providing me an opportunity to review their product, the latest iteration of their Planar magnetic IEMs, the Letshuoer S15. About the IEM, the S15 utilizes a third-generation 14.8 mm dual-chamber planar driver in conjunction with the proprietary 6 mm R-Sonic passive filtering module and employs a dual acoustic tube structure with a filter crossover scheme. As per Letshuoer, the dual chamber configuration gives S15 a broad soundstage, excellent transient response, and accurate sound reproduction; the Dual acoustic tube structure results in an excellent sonic balance. The 3D-printed sky blue chassis material is made of Resin and the face plate is made from Anodized Aluminium. The cable is 1.2 meters in length 216 strands of silver-plated monocrystalline copper. The IEM comes with 3 interchangeable L-shaped connectors 2.5mm, 3.5mm, and 4.4mm. 2 sets of tips – vocal and balanced in 3 sizes along with a rounded resin storage box are included. I did not try the balance tips but the vocal tips (Blue) were good. However, the seal wasn’t perfect. Hence I tip rolled and settled with Softears UC tips which provided me with a perfect grip and seal. At the time of this writing, the unit has undergone roughly 200 hours of my listening time. Overall sound profile of the S15 is balanced and neutral with a good hint of warmth. So, let’s dive into detail with the actualities of what this IEM is all about. As always, with my best intentions and abilities, here we go:

Before diving in, S15 has already been reviewed by 3 of my colleagues and friends at MBA – Mahir Efe Falay, Chris Love, and Pietro. You may check each of their reviews here, here, and here.

Specifications

• Third Generation14.8mm Planar Driver + 6mm R-Sonic Passive Filtering Module
• New Acoustic Structure, A Sound Quality Powerhouse
• Dual Acoustic Tubes with Filter Crossover
• High-precision 3D-printed Front Cavity
• CNC Precision Carved Aluminium Alloy Panel
• 216-strands Silver-plated Monocrystalline Copper Cable
• Detachable 2.5mm, 3.5mm, 4.4mm 90-degree Angle Connectors
• 0.78mm Dual-pin receptacle
• Impedance – 30 ohms
• Sensitivity – 106dB
• Frequency Response – 20Hz – 40kHz

Disclaimer:

• The review is my own based on extensive and critical listening and was not influenced by any written or video review. 

• The review is subject to unit variance and my personal listening preferences.

• The review is subject to the gears I used for testing – DAC/ DAP/ Tips/ quality of the track 

• Last but not least, I have no affiliation with the supplier of the IEM.

Gears/ Audio used for testing:

• S24 Ultra
• Tempotec V6
• Cayin RU7
• Topping NX7 Amp paired with the above 2.
• Aful Snowy Night
• Spotify Premium

Test Tracks:

This is a representative sample of the kind of music that I listen to most of the time – An inclusive list and not exhaustive. There are a lot more.

• Here we divide – Dead letters circus
• Landslide – Fleetwood Mac
• Make my move – Oliver Micheal
• Astronaut in the Ocean – Alok remix
• Code name Vivaldi – The Piano Guys
• Shout – Tears for fears
• Sandusky – Uncle Tupelo
• Cornflake Girl – Tori Amos
• Ice House – Ray Montford
• Dandelions – Ruth B
• Champion – Bishop Briggs
• Psychofreak – Camila Cabello
• Can you hear the music – Ludwig Goransson
• Beat – Tingvall Trio
• Strict Machine – Goldfrapp
• Fountain – iamamiwhoami
• You broke me first – Tate McRae
• Titanium – Sia
• You need to calm down – Taylor Swift
• Vachindha Megham – A R Rahman
• Shut Up and Dance – Walk the Moon
• Rihaayi De – A R Rahman
• Megham Karukatha – Anirudh Ravichandran
• Udi – Sanjay Leela Bhansali
• Danga Maari Oodhari – Harris Jayaraj
• Nan Pogiren (James Vasanthan).
• Naatu Naatu (RRR) – Keeravani 
• Kurchi Madathapetti (S S Thaman)
• Agar Tum Saath Ho (A R Rahman)
• Caribbean Blue – Enya
• Roygbiv – Boards of Canada
• Electric Love – Borns
• Take Five – The Dave Brubeck Quartet
• Rapid as wildfire – Genshin Impact
• Battlefield 4 Warsaw theme – Rami
• At the speed of force – Junkie XL
• Back in black – AC/DC
• Becoming Insane – Infected mushroom
• Chain reaction – Cloud Cult
• Hot girl bummer – Blackbear
• Memories of Dust – Nier Automata
• Pan – Plini
• Stress – Pain of salvation
• Love is gone – Slander
• You don’t own me – Saygrace
• Angel of Death – Slayer
• Somebody I used to know (Gotye, Kimbra)
• Leave them all behind – 2001 Remaster (Ride)
• Unity – Royksopp
• Unfinished Sympathy – Massive attack

Driveability/ Scalability

Letshuoer S15 is an efficient planar like the Hidizs MP145 which needs a decently powered  Dongle DAC to shine. I had a great listening time with all 3 – Tempotec V6, Cayin RU7, and Aful Snowy Night in the balanced mode independently. However, these scales well with an AMP say NX7 like any other Planar IEM does. Most of my listening and the impressions that are forming part of this review have been with Tempotec V6 or Cayin RU7 paired with Topping NX7.

Sound Quality

Bass

Sub-bass has an excellent tone, and decent depth, and is nicely textured. Has both satisfying quantity and quality. Rumble is decent when the track calls for it. Mid-bass is weighty, thumpy, impactful, and has a strong presence in the overall sound quality providing the needed warmth with an excellent body. However, Bassline is well separated here and never gave an impression of bleeding into the lower mids. Overall bass quality reveals a balancing act between sub-bass and mid-bass that sounds clean and very impressive. Sample test tracks – Royals (Lorde), Habits (Tove Lo), Bad Guy (Billie Eilish).

Mids

Mids are warm, lush, smooth, and detailed. Note weight is excellent which made me forget at times that I’m listening to a planar IEM. The instrumentation is detailed and spacious with excellent tone and timbre. Tonality is exceedingly natural for a planar IEM. Very good depth to the instrumental tracks. The vocals have a soulful rendition, probably due to how natural this IEM sounds. Everything is spaced well making it a very smooth and detailed listening experience. Both male and female vocals excel here with good energy. Sample test tracks – Varaha Roopam (Kantara), Agar tum saath ho (A R Rahman), Human Nature (Micheal Jackson), and Can You Hear the Music (Ludwig Goransson). Upper mids have no shout and harshness to them, although female vocals sounded overly energetic in the beginning which were tamed down naturally over time. Overall, excellent mid-range that is highly musical.

Treble

The treble is open, detailed, and airy. Not as energetic as the S12, however, tamed down in the right way. I still prefer the S12 for some energetic treble-heavy tracks due to its overall smoothness and excellent energy it has got, but the treble on S15 is done in a way that caters to a wider audience maintaining similar smoothness, and openness while slightly taming down the energetic presentation on the face. Nowhere sibilant on both the IEMs but S15 is easier to listen to, especially for longer sessions without any fatigue. Still energetic and not dark-sounding at all. I’m happy that the excellent qualities of the S12 treble are still intact. Excellent sounding treble that is detailed, open, energetic, spacious, and inoffensive. Thoroughly impressed. Sample test track – Leave them all behind (Ride).

Technicalities 

S15 is detail-oriented and is highly resolving expected of the price point. The soundstage was intimate at first but at around the 60-hour mark I noticed a natural improvement making it a tad wider, bigger, and overall, very spacious. The height and depth are excellent. Imaging is again top-notch being very precise and with positional accuracy. No loss in the audible trail. Layering and separation are excellent again – has the capability of deciphering the complex tracks with ease. The tone and timbre are fantastic and a highlight of this IEM. Transient response is seamless and excellent. Overall, brilliant technicalities. Sample test tracks – Hunter (Bjork), change the world (Eric Clapton), Bubbles (Yosi Horikawa).

Letshuoer S15 Comparisons:

The comparisons I have here are the Letshuoer S12, Hidizs MP145, TinHifi P1 Max, and the Aful Performer 8. S12, MP145,  P1 Max, and Aful Performer 8 are in their stock form except for the tips – changed to Divinus Velvet for all 3 planars and Spinfit W1 for P8. Source used for comparison: V6 + NX7. I always use Tempotec V6 in my comparisons because it never sounded bad or off with any IEM I listened to and maintains a very good synergy with neutral transparency. And NX7 is to allow every IEM to perform at its best irrespective of the driver type and the configuration. It is as source-transparent as it can be providing a clean output power of 1400mw at 32 ohms which can drive any IEM with ease. I brought P8 into the comparison because it is a class-leading IEM at its price point and a worthy competitor to compare against the similar but slightly lower priced S15 – ultimately we all would like to know if S15 is worth its asking price, right?? Let’s find out:

Vs Hidizs MP145

In terms of fit, I prefer the S15 which gives me a better seal and is more comfortable on the ear. The cable termination on MP145 is angled slightly upwards resulting in the hooks coming off easily especially while lying down. Tips with a great seal are a must here to hold the IEM in place. MP145 ear hooks are comparatively easier on the ear whereas the S15 ear hook is a bit aggressive. Also, the MP145 is built like a tank in comparison. S15 comes with 3 terminations – 2 balanced and one single-ended, whereas MP145 comes with 3 tuning filters. Both are relatively easier to drive compared to the other Planars that follow down the lane. I enjoyed both of them listening using Cayin RU7 and Aful Snowy Night in high gain. 

Coming to the sound, I see there are three major differences between the two which sets them apart, favoring the S15. However, these differences come with a big difference in price tag too and I can’t complain much about the MP145 for the price it is being offered.

• The first is the tone. There is a hint of planar timbre noticeable now and then with MP145 whereas S15 sounds very natural like a DD to my ears. Any track that I listen to, S15 distinguishes itself in terms of tonal quality which appears way too natural to me. MP145 is not far off but I didn’t enjoy the tonal quality of the MP145 as much as S15. Sample test track – Blood on the Cobblestones (Mikolai Stroinski – Witcher 3).
• Second is the upper treble performance. I mentioned in my MP145 review that the upper treble is not very open sounding and is subdued and dampened to an extent – the splashes etc. I still stand by that and S15 sounds to me as a clear winner here. It is not as energetic or vibrant as the S12 which can be a good thing for treble-sensitive listeners but S15 sounds smooth like the MP145 but more open without any undue taming of upper treble energy. Sample test track – Lux AEterna (Metallica).
• Third is the mids section. Lower mids are slightly recessed on the MP145. The instrumentals and male vocals sound a tad thin at times and the difference is more noticeable when compared with S15. S15 sounds fuller in comparison. I can hear every bit of detail in the instrumentation more on S15 compared to MP145. Sample test tracks – Stronger (Oliver Michael), The Last of Mohicans (40 Fingers), People Are People (Depeche mode).

Now coming to minor differences and commonalities, Bass is very similar – both the sub-bass and mid-bass. Both are on the neutral side, the S15 slightly sounding warmer; Both the IEMs satisfy even the bass heads in my opinion as they both are no slouch in the bass department. Sub-bass presence is strong but does not go very deep on both. Rumble is present when the track calls for it on both sets as the sub-bass decays faster with planar. Sub-bass depth is slightly better on the MP145 and so is the rumble. Texture is slightly better on the S15. There is a strong emphasis on mid-bass over sub-bass on both sets. But it appears to be a balancing act between sub-bass and mid-bass on both sets. Mid-bass is weighty and thick on both the sets and as Planars resolve faster, the thickness does not stay a while and decays faster – A good thing for keeping the mids very clean. Good body nevertheless. S15 has a slightly more body in the overall bass region making it sound fuller and warmer than MP145. Slightly more resolving as well. As far as the mids, note weight is slightly better on the S15. I loved the instrumentation on the S15, being more natural sounding. Upper mids are well done on both. No shout or harshness was noticed and female vocals sound solid on both. 

Note weight makes a difference here regarding one’s preference towards the soundstage – MP145 sounds more crispier creating a sense of more space. It creates an imaginary space littered with instruments. While the stage on S15 is as close and resembles the MP145, especially post some burn-in, the lush note weight occupies much of the stage leaving less room compared to MP145 in terms of our brain’s perception of the massive spaciousness the MP145 creates. S15 balances well here between the note weight and spaciousness, while the MP145 has a slightly recessed lower midrange making instruments sound a tad thin. As a result, the stage appears a tad more spacious on MP145 with delicate and crispy instrumentation. The feeling ‘on your face’, the S15 can give you sometimes just like its predecessor the S12, but overall better.

Imaging is excellent on both sets. Precise and defined. No issues in the sets tracing the audible trail. Transient response is excellent on both sets. Although both have a good depth, stage depth is slightly better on the S15. Height appears the same. Resolution and detail retrieval are better on the S15. Layering and separation are also better on the S15. Sample test tracks – Ice House (Ray Montford), Big Sur Moon (Buckethead), Bubbles (Yosi Horikawa), Caribbean Blue (Enya), Mental Madhilo (A R Rahman). 

“To sum up, although MP145 is an excellent technical performer at its price point, S15 is an overall all-round upgrade to MP145.” 

Vs TinHifi P1 Max

There are more similarities than differences between the two in terms of overall tonal quality and the sound. Both sound very natural without any hint of planar timbre. I find the fit of both of them similar covering the whole of the inner ear. No issues with both sets in terms of fit. Of all the 5 IEMs here, I find the P1 Max is harder to drive and needs an AMP like NX7 to perform at its best. That too it comes with a 3.5mm termination only, I never tried with any balanced cable to be honest as NX7 always comes in handy blowing my socks off and I love the P1 Max cable. I find them even more comfortable than the S15 ear hook design. So, I can’t say how it scales well with a balanced cable and a source. Never cared to try.

Coming to the dissimilarities, technicalities come first. It’s not like night and day at first but becomes more obvious when you listen to one IEM after the other, track by track. Otherwise, it is difficult to pinpoint a difference straight away. They sound very similar tonally. Subtleties are where S15 shines due to excellent resolution, seamless transient response, layering, and separation. As a result, S15 sounds more sophisticated, refined, and mature compared to P1 Max throwing more details at you. Both have a similar but accurate stage width. P1 Max sounds wider when the track calls for it – similar case with the S15. Note weight is better on S15 as well often sounding very full. P1 Max is not much behind and has the crispier sound of the two – boils down to listener preference here. Detail retrieval is the best on S15, thanks to the burn-in, S15 has come a long way since my initial impressions. Stage depth is lacking on the P1 Max whereas it is opposite and excellent on the S15. Imaging is more accurate and defined on the S15. 

Sub-bass and mid-bass sound very similar and it boils down to resolving capabilities where the S15 stands out. Both have adequate warmth to their sound and are tonally very similar except that the S15 sounds more fuller with better note weight. Mids sound lusher and more musical on the S15. The vocals sound great on both the sets. There is no harshness or shouting in the sets. I have no issues with the treble on both the sets as well except the treble is much smoother and is more refined and detailed on S15. P1 Max can get borderline sibilant in certain tracks for some but that is not the case with S15. 

“To sum up, S15 is a definitive upgrade for the fans of P1 Max in particular, especially the technicalities which make a bigger difference here.” 

Vs Letshuoer S12

I will start with the dissimilarities. First the treble. S15 can be regarded as an iteration of S12 soothing down the energetic treble, improving the detail, and positioning more friendly to the treble-sensitive listeners, but to me, S12 is still legendary in terms of overall treble performance. The impeccable energy that is often on your face while maintaining utmost smoothness, crispiness, and openness is simply unmatchable, even with the S15. However, as a result, S12 comes with one downside with the treble i.e., fatigue. Although I have a tolerance for it as it is smooth sounding in general, that may not be the case for everyone. Hence the S15 – the iteration that was done right taming down the energetic nature and retaining the other excellent qualities of the S12 treble – openness, and details. Resulting in a smoother, non-offensive, detailed, open, and airy treble performance. I can say S15 is a natural upgrade to S12 in terms of treble. However, I still prefer the S12 in certain treble-heavy and energetic tracks. Regarding the fit, the S15 is better overall compared to the S12’s loose fit which is very much tip-dependent. 

Mids sound very lush and soothing on the S15 with excellent note weight and balance whereas S12 has the energetic and crispier sounding mids. Sounds more V-shaped compared to S15. Somehow, due to the energetic ‘on the face’ nature of the mids, details in the mids are clouded compared to S15. The vocals are excellent on both the sets. I cannot pinpoint which I prefer more. The nature is the same as how the mids perform in general. Sample test tracks – Kurchi Madathapetti (S S Thaman), Nan Pogiren (James Vasanthan). 

Sub-bass depth and texture marks only a very slight improvement over the S12. Mid-bass is more or less identical on both. I didn’t notice a big difference when it comes to bass except for the note weight and technicalities that can make a difference in the way we perceive overall bass performance. Technically, S15 is a refined S12 in general. The big difference is the resolving mids/ details in the mid-range, somewhat clouded on the S12, and the excellent tonality. Layering/ separation, transient response, resolution, and imaging are all an improvement over S12. Although the head stage is bigger on the S12, stage depth is kind of lacking. S15 has a great stage depth. Stage width is better on S15 as well. 

Both the cables are great but the ear hook design is kind of aggressive on both. However, I find the S15 slightly better than the S12. Also, S15 comes with 3 terminations. 

“To sum up, the S15 is an upgrade as well as the subtler version of the S12. I’m still a fan of OG S12 treble but it may not be apt for everyone, especially for longer listening sessions. The main reasons to choose S15 are its excellent tone, soothing midrange/ treble performance, and overall improvement in the technicalities.”

Vs Aful Performer 8

I love the fit of the P8 more than any other IEM in my collection. Even a medium-sized tip provides the perfect seal for me. So, no comparison in this regard as P8 is an outright winner here. P8 is fairly easy to drive compared to S15 and scales very well. P8 comes with a 3.5mm termination only.

The overall bass performance on Letshuoer S15 is slightly better than the P8 for me. There’s more body and a balancing act between the sub-bass and mid-bass on S15 compared to P8. P8 has a very good resolving sub-bass presence and since DD takes care of the Bass on P8, the presence is slightly more felt on the P8 but the quantity on S15 makes up for it. The mid-bass on the S15 thumps, is weighty with good body and is impactful whereas the P8 does the job equally well but with a slightly lesser quantity. Resolution in the mid-bass is great on both. The depth of the sub-bass and its texture are similar in both. Both do not go very deep. Separation in the bass region is great on both making it distinctly audible. Due to the quantity, I tend to prefer the S15 more which is a tad more impactful and warmer overall leading to a more musical experience.

Although both sound fuller to me, S15 has even better note weight probably due to more warmth from the mid-bass. The tonality is excellent and appears very natural on S15 where whereas there is a slight BA timbre which is noticeable only in comparison. Mids sound smooth, lush, and a bit warmer with clean separation from the bass on the S15 whereas the P8 has a crispy note weight with an undeniably good body and is too detail-oriented. S15 is detail-oriented but P8 is just on another level – tracks with good micro details give sublime experience on the P8. I prefer listening to instrumentation on P8 more than S15 – it is just that good thanks to the multiple driver configuration. But still, S15 is no slouch here which then brings us to musicality – S15 sounds more musical/ emotive compared to P8 – that has mainly to do with how natural S15 sounds. Vocal clarity on P8 is excellent – both male and female. Slightly forward than S15 and is clearer and more energetic in comparison. Sample test track – Somebody I used to know (Gotye, Kimbra). Upper mids are slightly more energetic on P8 compared to S15 – both are inoffensive to me.

Treble sounds great on both sets. However, it is more airy, smooth, spacious, and open on the S15 compared to P8. P8 treble is more energetic than S15 and may trouble treble-sensitive listeners, especially in the treble-heavy tracks. S15 on the other hand is treble-sensitive friendly. Although the details in the treble region appear to be the same, they are slightly better perceived on the S15 due to the overall smooth and spacious sound. Again, the BA timbre on AP8 is noticeable here in comparison. Sample test track- Giorno’s theme (Friedrich Habetler). 

The resolution is neck to neck between the two. Both are very resolving and detail-oriented. P8 has the best detail retrieval in mids whereas S15 is better in treble. Tonality goes to S15 by a good margin. Layering and separation are slightly better on the S15. Sample test track – Time after time (Cyndi Lauper). Stage width and depth are slightly better on the S15 over P8. Height appears to be the same. Transient response is excellent on both sets and I slightly prefer P8 over the S15. Imaging is better on S15 as it is more precise on the tracing. 

“To sum up, S15 is more musical whereas P8 is more analytical. That does not mean the technicalities of P8 are better than S15. It is just that the S15 is musically so good, that I tend to forget at times that the S15 is technically impressive too. Whereas I prefer the P8 for its detail retrieval in the mids – instrumentals/ vocals; and transient response in general, for the rest I prefer the S15. The differences do not set them apart too widely either. But differences are still differences at the end of the day; And so, S15 is an overall winner here since it excels both musically and analytically and costs less in comparison.”

Pros:

• Exceedingly good tonality and note weight

• Highly musical while being analytical

• Balanced sound profile

• Solid bass response

• Lush, smooth, detailed, and inoffensive midrange

• Soulful vocal performance

• Open, smooth, airy, detailed treble performance

• Highly resolving and detail-oriented

• Spacious staging with precise imaging

• Layering and separation are very good

• Modular cable with 3 swappable terminations

• Very good unboxing experience

• An efficient planar in terms of power requirement

• Lightweight on the ears

Cons:

• Sub-bass could have been a tad deeper

• Not as energetic as the S12 anymore (subjective)

• The ear hook design can cause slight discomfort around the ears at times

• Personally, not a fan of L-shaped termination

• Niche price segment for some considering the planar market

• May not be the most attractive-looking IEM (subjective)

Review closing thoughts:

To sum up my final thoughts, Letshuoer S15 is a perfect all-rounder IEM. No two views about it. There are no obvious flaws with this IEM that let me down in any way.  During my early listening sessions, the stage width was more intimate and the upper mids especially the female vocals sounded overly energetic in certain tracks. I see a natural improvement over the time. The stage has widened bigger and better and the upper mids started sounding more natural over time. Letshuoer S15 does everything well expected of its price point and comparison with a similar priced IEM – Aful Performer 8 does justify the same. I’m profoundly fond of this IEM for its natural tonality, musicality, and note weight that is crispier and fuller at the same time, setting itself apart from the other praiseworthy planar IEMs. The brilliant technicalities are the icing on the cake. The IEM is equipped with a modular cable with 3 terminations that comes in handy with any source. Well, is it worth the asking price? I believe, with a resounding YES. 

“S15 in general is an excellent sounding set at the given price point, irrespective of the driver configuration. Technicalities are intertwined with Musicality which is the soul of S15 above everything, offering an unparalleled musical experience.”