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:
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
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
