Letshuoer S15: a new competitor?

The Letshuoer S15 reviewed in this review is the demo unit of the kopfhoererboutique audio store in Vienna.

Letshuoer S15 is Letshuoer’s newest entry in the Planar IEM world, coming at the cost of 329 USD. It contains a new generation 14.8mm Planar driver and a diaphragm as a filter (aka. "6mm R-Sonic Passive Filtering Module"), marketed as a "technological breakthrough". But is it worth it?

Build and comfort

The S15 is made out of a metal faceplate and a 3D-printed shell, which feels a little bit more premium than the “normal” plastic builds which you can find on cheaper IEMs. It comes with a cable which is basically a mix of a S12 Pro and EJ07M cable (S12 Pro cable with EJ07M L-plug). Furthermore, the cable is modular, so you can switch the cable from a 3.5mm Single Ended one to a 4.4mm Pentaconn or 2.5mm Balanced cable if you want to.

The set of IEMs actually fit weirdly in my ears. I had to toss the IEMs a little bit to get a secure, non-fatiguing fit – and I was just not used to that fit as the ear hooks had to be very near my helical crus.

Other than that, the cable was qualitatively similar to the ones on my S12 Pro and behave very similarly too.

Sound (Tonality, Technicalities and everything in-between)

The Letshuoer S15 has been tested with a Questyle M15 DAC/AMP and my Xiaomi 11T using Hiby Music Player.

Letshuoer S15 adopts the sound signature of the better Planars and lowers the Bass and the Treble by a little bit.

A slight rise in the Sub-Bass and Bass region (from 20Hz up to 300Hz) is noticeable, followed by a slight recess at around 800Hz.

The well-known pinna shape of the Planars and various high-end IEMs like 64Audio U12t, Nio, U6t, Volür, etc. – therefore also known as the “64pinna” – is still implemented on the S15. Which means: a 2kHz peak followed by a 3kHz recess and then a rise to around 10kHz.

Starting from 10kHz is a Treble shelf, making it sound bright. Take that with the lacking punch and you find a bright-tilted, V-shaped set of IEMs.

The decay on these IEMs is quite fast, it can hold up with fast-paced tracks like “命日” by LeaF, where at 1:49 the Kicks become the Bass, essentially.

The timbre of these IEMs is not very accurate, since the piano on the same track sounds pretty unnatural and decays a little bit too fast. Dynamic drivers do a better job on this.

Another thing which is affected by Decay is the Bass dynamics, macrodynamics, compression – you name it. In that regard, Letshuoer S15 is pretty mediocre. S15 still has that “Planar timbre” where the Midbass seems lower than it actually is. The Kicks and Snares aren’t “punching” you a lot, and they sound a little too compressed compared to most Dynamic Drivers managing the frequencies below 300Hz.

On the contrary, the Sub Bass is very noticeable if you ignore the Treble.

Microdynamics/Treble response on S15 is... a little bit behind a lot of the Planars. It surely does sound distinct, but only in slower-paced tracks (tracks under the tempo of 140bpm).

Now to my own opinion, Letshuoer S15 is quite a joke in what it’s supposed to do. Sure, it’s very resolving but that Treble is very harsh. It’s like trying to sharpen an image in hopes to make the image more “detailed”, resulting in a smeary image. It’s not even “sparkly” anymore. The Midbass is also quite underwhelming – the compression applied here is a bit too much. The only thing about S15 that I like is only the Sub Bass, which is very satisfying in my opinion.

Drivability

Letshuoer S15 can be driven by a simple dongle like the Apple dongle, though I would discourage people from using the EU version of it (Model number A2155) on Android, unless you are using USB Audio Player Pro or Hiby Music Player.

Comparison

Comparison was made with Questyle M15 and Xiaomi 11T using Hiby Music Player.

I will compare the Letshuoer S15 to my Letshuoer S12 Pro, as the original S12 is essentially just a S15 with more Bass and Treble.

Letshuoer S12 Pro can fit me much better than S15, as I am used to how I wear S12 Pro. Though S15 can also fit quite deeply in my ears without me being fatigued by it – I am just not used to it.

Coming to sound, S12 Pro is noticeably smoother in the Treble than S15 and is therefore also “sparkly”. S15 on the other hand sounds harsh compared to S12 Pro. For example, take the song “Unsteady” by SOUNDR, ROY KNOX and Lost Wolves and you’re hearing much more harshness on the S15 compared to the S12 Pro. In fact, I’m getting fatigued when listening to every Melodic Bass track I have when using S15. Weirdly enough, S12 Pro could handle Melodic Bass very well for me.

When switching to my own track “Unforgettable Memories”, the synth on the first drop of the track (1:00) sounds harsh compared to S12 Pro.

Now when listening to a Briddim track like “Spacetime VIP” by Subtronics and NEVVE, Letshuoer S15 makes the female vocals very harsh and the textures in the fakeout and beat drops exaggerated and fatiguing, while S12 Pro is just at the border of being fatiguing there – makes sense, the track itself is also fatiguing in itself.

I would gladly take my S12 Pro over S15.

Conclusion

So, do I recommend Letshuoer S15? Unlike most reviewers who reviewed S15, definitely not. There is Letshuoer S12 Pro for much less expensive and less fatiguing. And you could just go for cheaper, safer IEMs like the Truthear Hexa. Letshuoer S15 is definitely overpriced and you should look elsewhere if you want something worth the price.