Letshuoer S12 Ultra Review: Superior Evolution?

Letshuoer S12 Ultra Review

My first ever IEM from Letshuoer is the S12 Pro, as I wanna try a good planar driver earphone. To be honest, that was not a good idea, because I’m very sensitive to spicy treble. So, when they released the S12 Ultra, and I learned from some reviewers that these IEMs are not as spicy as the S12 Pro, I was very interested to try them, as Letshuoer calls it the “calm evolution” of a classic. Is this another bad decision for me like the S12 Pro? That will be explained!

They remain a bit spicy to my ears, especially the upper midrange and the treble. But with almost 100 hours of burn-in and some cable and tip rolling, they gave me a manageable listening experience. Is it perfect? No. But it’s a damn good reminder that evolution doesn’t always mean revolution. If you’re treble sensitive and can’t take spicy planar timber, you shouldn’t pair it with any bright sources. A warm-balanced source can help you in this regard.

DISCLAIMER

Letshuoer was kind enough to send me the S12 Ultra to review. I am not affiliated with Letshuoer, and of course, I was not asked for any copy-checking before publishing. All opinions shared in this ‘Letshuoer S12 Ultra Review’ are my subjective thoughts.

One more thing: The review is based on my personal experience and what I hear from various sources. Your experience may vary due to personal preferences and physical differences, such as the shape and depth of the ear canal.

For your personal purchase, checkout Letshuoer for their fantastic products and promotions (non-affiliated link).

GEAR USED

●   DAP: Cowon Planue R2, Cayin N3 Ultra, Hiby RS2, Hiby R4, Snowsky Echo Mini, F.Audio M20.
●   DAC/AMP: xDuoo MT-604, Fosi Audio GR40, Hiby FD5, KAEI Design TAP2, ifi Hip DAC 2, xDuoo XD-05 Plus (with MUSES 8820 OP-Amp), Cayin RU6, Cayin RU7, iBasso DC04 Pro, Dunu DTC 480, Fosi Audio DS-1, Celest CD-10, Celest CD-20, Hiby FC05, Hiby FD03, Moondrop Dawn Pro.
●   Smart Device: Poco X3, Xiaomi MiPad 5.
●   Files: Tidal, Qobuz, Spotify, local Hi-Res FLAC & DSD files.

AUDIO TESTING PREFERENCES

I desperately love the music from the 60s to the 90s era. Music was alive then. The genre I love most is ROCK ‘N ROLL. Though Jazz, Blues, Metal, Disco, and Pop are also my favorite genres. I have a collection of albums with high dynamic range recording. Most of the time, I test audio gear with those albums to understand the sonic capability of the specific gear. If you have a Tidal subscription, you may click here to get the playlist.

TECHNICAL SPECIFICATION

● Driver: 14.8mm planar driver
● Frequency response: 20Hz – 20kHz
● Impedance: 16Ω
● Sensitivity: 101dB
● Cable: Silver-plated copper
● Pin Type: 2pin, 0.78mm
● Cable Length: 1.2m
● Plug Type: 3.5mm,4.4mm & DT01 Pro 3.5mm to Type-C DAC

WHAT’S IN THE BOX

● Letshuoer S12 Ultra IEMs
● Silver-plated copper cable
● 3.5mm & 4.4mm plugs
● DT01 Pro 3.5mm to Type-C DAC
● 2 types & 3pairs (S/M/L) soft silicon ear tips
● Carrying case
● User Manual & official papers

UNBOXING EXPERIENCE

A nice little cardboard box holds everything you need to enjoy this IEM. I like the minimal footprint, as it is echo-friendly. The inclusion of an interchangeable cable is always a nice touch for this S12 series. This time, the cable looks more premium than the one for my S12 Pro. You will also have two types of ear tips in the pack, one ‘balanced’ and the other ‘vocal.’ Moreover, they include a USB-C DAC dongle, the ‘DT01 Pro,’ which has only a 3.5mm output. I will say the experience is really ‘top-class,’ as always.

BUILD & DESIGN

The S12 Ultra is made of aluminum alloy and feels very sturdy for everyday wear & tear use. Letshuoer has taken and is still taking good care of their ‘S12’ series. The surface of the IEMs is really smooth and has no hard edges on the part that submerges inside the ears. There are two ear vents on each side, which, in my opinion, is a brilliant design idea. Without any question, it’s a very well-built & fantastically designed IEM.

FIT & COMFORT

The S12 Ultra really seems like a custom-made earphone for your ears. They fit perfectly on any ears due to their smart size. Though all of the ‘S12’ series IEMs are praised by users for their good fit. And for those smooth-finished aluminum shells, the comfort is top-notch. The nozzle size is 6mm approx., and it has a good grip to hold the ear tips perfectly. For listeners like me, who used to enjoy their music for 5-6 hours straight, these can be one of the most comfortable IEMs.

SOUND IMPRESSIONS

This is a planar driver, so keep in mind that it has some good ‘spice’ like any other planar IEMs. The bass is the hero here, almost like something from a well-tuned DD. But midrange is where it starts to show the ‘planar timber,’ especially in the upper-midrange area. And for me, the treble seems a little fatiguing.

Here is the frequency graph :

Let’s dive deep…

SUB-BASS

If you’ve been into this hobby for a long time, even a year or two, you already know the ‘rumble’ of a well-tuned DD IEM’s sub-bass. With the Letshuoer S12 Ultra, you will hear the same. It’s a true hearing, not just feeling the presence. The quality of the sub-bass is top class, with good control and authority. It will hit your eardrum well while staying in the lower region, not all over the place. That being said, it never bleeds into the midrange and makes it muddy. Letshuoer tuned it with both good quality and quantity. But is it bass-head level? I don’t think so!

MID-BASS

A mid-bass that will soothe your ears with the perfect slam- that’s all I can say. I always love mid-bass, which carries a good weight and has good texture. Though it is the main characteristic of ‘DD mid-bass,’ when you fall in love with a specific kind of ‘sound,’ you will hunt for it everywhere. The S12 Ultra surprises me just the moment the kick-drum hits the first stroke! That control, that meaty thump… ah man, it’s so good enough! But in the end, it’s a planar driver, so it has some drawbacks compared to DD. Though the mid-bass has a good presence, it’s still a little bit leaner and less impactful.

VOCALS

To me, the IEMs make me feel mixed up when it comes to vocals. And that’s where things are getting a bit uncomfortable for me. Let me explain.

MALE

To my ears, the male vocals presentation is good. It carries a good weight from the mid-bass, but never gets muddy or muffled. It shows excellent body with a good melody. And the texture? Ah, nice. I don’t like the flat kind of male vocals, and I’m very fond of meaty and textured ones. S12 Ultra delivers it right. And it’s a little lean kinda presentation, though I love it cause I don’t enjoy too much forward vocals. Though in some busier tracks, the male vocals feel too backward! I can easily hear them; they remain clear, but getting too mixed up with the instruments ruins my enjoyment.

FEMALE

I must confess that this is the section where I lost interest in having a long listen! In my other reviews, I already stated that I’m very treble sensitive. Especially the spiciness in the upper area gives me fatigue every single time. When the S, SH, T, and TH sounds are sharp, I can’t take it. In my opinion, this classic planar timber in the upper midrange is still present in S12 ultra, like the S12 Pro! Female vocals come out with good energy and spark. They are a bit forward in nature and have raw power with a super melody. Shiny, sparkly female vocal lovers will enjoy it, I think!

INSTRUMENTS SEPARATION

In the S12 Ultra, separation is good enough for a planar driver. One of the best instrument presentations under $200 IEMs. Compared to the S12 Pro, the Ultra is slightly less sharp in separation. The layering is clean, and you can easily pick out each instrument placement in any moderately busy rock or jazz tracks. But when the composition gets busier, like some heavy metal or progressive rock tracks, that’s where the IEM losses it’s control. They don’t get too muffled, but they show a bit of a congested kind of presentation! Though it’s not the cleanest separation, but for most genres, I think, it’s more than adequate.

TREBLE

Despite the sibilant upper midrange, the treble stays smooth. Any audio lovers who appreciate quality treble will fall in love with these IEMs in no time! Who doesn’t love a good treble? Nobody! right? Though the S12 Ultra’s treble is not spicy like the OG S12, it still has that classic ‘planar treble’ kind of thing, but you can easily ignore it because it’s very well-managed. This time, the ‘evolution’ is real. It’s not ear-biting kind, rather it is very well extended, smooth, and airy. Crispy, edgy treble lovers will find it a bit polite. Sorry, mates!

SOUNDSTAGE

I found it to be a decent type of thing, not expensive. I mean, the left-right width is good enough to enjoy the true stereo thing. But if you expect a holographic stage, like the experience in any concert hall, no, it’s not there. The good width will give you a sense of space, but the height and depth are really limited. Due to good instrument layering, the imaging is commendable in most of the tracks. But in busier tracks, the stage feels a bit narrow but never ‘on your face,’ or very congested! The stage is well-balanced between dimensions, which adds to the natural, organic feel of the sound.

TECHNICALITIES

Dynamics: The S12 Ultra has good macro-dynamics. It handles volume swings and intensity changes with authority, and the bass impact is satisfying. Micro-dynamics are decent but not exceptional. It’s punchy enough to be engaging, but not a dynamic powerhouse.

Speed: Transient response is fast and clean, as you’d expect from a planar driver. Notes start and stop with precision, with no smearing or blurring. This speed contributes to the overall clarity, but sometimes may feel a bit polite rather than aggressive.

Analytics (Detail Retrieval): Detail retrieval is good but not class-leading. You get a solid amount of macro-detail, like the texture of a guitar string, the breath of a singer, but it’s presented in a musical way rather than shoved in your face.

SOURCES

Source pairing is important because planar drivers are generally power hungry. You can’t expect to drive it from your smartphone’s 3.5mm port, and it will open up its full potential. No, that’s not gonna happen, bro. Even the supplied DAC dongle from Letshuoer, the DT01 Pro, is not a good match, in my opinion. It sounds thin and bright. You may try some warm-tuned DACs like the Cayin RU7, ifi Hip DAC 2, or a desktop tube DAC-amp like the FosiAudio GR 40. They are all capable enough to drive any power-hungry planar IEM and are able to deliver warm tonality to tame down the spiciness on the upper midrange to the treble area!

CABLE & TIP ROLLING

The stock cable of the Letshuoer S12 Ultra is a premium one and really comfortable to use. You don’t need to buy any aftermarket cable. But if you have a pure copper cable in your collection, you may try, as I find that pure copper cable can help to reduce the spiciness in the upper-mids a bit. The stock tips are good to use, as they are soft and comfy. But I prefer something like the Penon Liqueur Orange ear tips, because they have the ability to make the treble and upper area a bit smoother.

FINAL THOUGHTS

If you let me choose any planar driver IEM, I will say the legendary Hedizs MP 145 any day, any time. Though they are bulkier than the S12 Ultra and fit is a bit challenging, the sound they provide is the same as my preference level. And also, MP145 OG has a holographic type of soundstage. But it’s not a good thing to praise another IEM while writing on a specific model, right?

So, what’s my final thought on the Letshuoer S12 Ultra IEMs? If you love V-shaped sound with very controlled, textured bass presentation with smooth, airy treble, and spice in the upper midrange is not a problem for you, then why not give it a try?

Moreover, it is very comfortable to wear and fits almost every ear! The build is top-class and very lightweight. The interchangeable cable and the DT01 Pro DAC are a plus point.

WHATEVER YOU’RE THINKIN’ OF BUYING—DAC, DAP, IEM, HEADPHONE, AMP, WHATEVER—JUST MAKE SURE YOU GIVE IT A DEMO RUN FIRST. TRY IT OUT, LISTEN TO IT WITH YOUR OWN TRACKS. SERIOUSLY, ONE QUICK AUDITION CAN SAVE YOU A BUNCH OF MONEY AND REGRET LATER ON.

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