Letshuoer recently released the Ember, a limited edition flagship single-driver planar magnetic IEM. Although the Ember looks very similar in design to the S15 (launched 2023/24) and uses a driver of the same size, Letshuoer states that the driver is completely new. It is limited to 999 units, priced at 499 USD.
Meanwhile, the S12 Ultra is the fourth generation of the S12 series. Interestingly, it was released some time after the very similar sounding 2024 Limited Edition m, which suggests that Letshuoer might do something similar with the Ember’s technology if it proves successful. The S12 Ultra is also equipped with a 14.8mm planar magnetic driver and is priced at 169 USD, which includes the excellent DT01 Pro USB dongle. My S12 Ultra review can be found here.
LETSHUOER S12 ULTRA SPECIFICATIONS
- Driver: 14.8mm planar magnetic
- Impedance：16 ohms
- Sensitivity：101dB
- Frequency Response：20Hz – 40kHz
- Material: Aluminum alloy
- Cable: 1.2 m Silver-plated copper
- Cable connectors: 0.78 mm 2 pin
- Cable termination: 3.5 mm and 4.4 mm interchangeable jacks
- Included: Ear tips, DT01 USB dongle (3.5 mm output) and Puck shaped storage box
Current price and availability:
LETSHUOER EMBER SPECIFICATIONS
- Driver: 14.8mm custom planar magnetic driver
- Impedance: 30 Ohms
- Sensitivity: 103dB
- Frequency response: 20Hz~40kHz
- Housing: titanium alloy shell + aluminum alloy faceplate
- Cable: 26AWG, 4 core, UP-OCC monocrystalline copper
- Cable connectors: 0.78mm universal dual pin connector
- Cable termination: 4.4mm balanced gold-plated jack
- Included: ear tips and puck shaped storage box
Current price and availability:
LISTENING COMPARISONS
Associated equipment:
- Amplifier: Topping A90
- DAC: RME ADI-2 DAC FS
- Ear tips: AZLA SednaEarFit Xelastec on the Ember, SpinFit CP145 on the S12 Ultra
Moo)n by Lindström
The Ember delivers greater bass quantity and overall better resolution. It generally feels tighter and more detailed than that of the S12 Ultra, even though the bass is richer.
Dancing in the Dark by Jørgen Dahl Moe
Both are good, the Ember is cleaner and smoother, with more warmth.
Cloud Wars by Medeski, Martin, and Wood
The bass of the Ember is quite strong, but in terms of quality it is excellent. Overall, it is smoother, darker, and warmer than the S12 Ultra, which has noticeably less bass quantity and sounds crisper in general.
Alt e bra by Building Instrument
This sounds very good on the S12 Ultra, with a nice open soundstage and a well balanced sound profile. Nothing sounds bad or off, it is a very nice listen. Switching to the Ember, however, things sound even better, more refined and more hi-fi. The bass is of course a bit more powerful, but it is not really much of a difference on this specific track.
Golden Horn by Joe Lovano
The Ember is really impressive. The level of detail is fantastic and the imaging is impressive. It is again darker and lusher, with thicker bass than the S12 Ultra, which has a similar sound signature here with roughly the same bass quantity, but is a bit brighter in the mids especially, making it more upfront. On its own it feels detailed and adequate, but in direct comparison there is clearly better resolution with the Ember.
Meslange de musique latine, fra.. by Sophie de Bardonnèche Destinées
The S12 Ultra sounds excellent, with a neutral, slightly crisp instrument timbre on the strings and harpsichord. The Ember is slightly darker and lusher, smoother and more refined.
Young Vivaldi by Modo Antiquo
Excellent timbre and detail on the Ember. It is darker and smoother, while the S12 Ultra is markedly brighter and crisper in comparison, but still very nice.
Summer 3 Vivaldi Recomposed by Max Richter
Also here, the Ember is darker and smoother, while the S12 Ultra is crisper and brighter. I like both; they are subtle variations rather than stark contrasts. The Ember offers a more refined sound, while the S12 Ultra delivers more bite and attack.
Jambi by Tool
The Ember is again darker, smoother and more warm, while the S12 Ultra is crisper and brighter — although the S12 Ultra isn’t especially crisp or bright in absolute terms.
Midnight City by M83
The Ember is smoother, lusher, darker, and more laid-back. The S12 Ultra is more articulate and upfront, but the difference in perceived detail isn’t very large here.
Rambling Man by Laura Marling
I really like the smooth and laid-back presentation of the Ember; it’s delightful. The S12 Ultra is crisper and more upfront, but also very good—probably more neutral, though somewhat less refined.
Limit to Your Love by James Blake
The challenging bass is extremely controlled on the Ember, even better than the already quite good S12. In general, it is again smoother and lusher in the mids and highs.
WRAPPING IT UP
Sound Signature
The S12 Ultra has a fairly neutral tuning with what could be called a natural-sounding bass quantity—not the flat, studio-neutral type. The Ember has more bass and is generally darker, warmer, and smoother.
Treble
Both have good treble, but the resolution is better on the Ember, and it is also slightly darker and less crisp.
Midrange
The mid-range on the S12 Ultra is more upfront, crisper, and brighter compared to the Ember’s darker, lusher delivery.
Bass
There’s nothing really lacking in the bass quantity of the S12 Ultra, but the Ember takes it a bit further, boosting the bass noticeably. Even though it’s often very nice, I would personally prefer a more neutral bass on the Ember…. However, it has exquisite bass quality, even better than the already great S12 Ultra.
Soundstage and Imaging
I find both to have a nice open soundstage and good imaging, but the Ember, being more refined and having better resolution, also offers better imaging with improved instrument separation and layering.
Detail, Dynamics, and Timbre
As mentioned, the Ember has better detail, but it delivers it in a smooth and refined manner. The S12 Ultra can often sound more articulate and, in many ways, is better at micro-dynamics, or at least makes them more pronounced. I also think general dynamics are comparable, though it depends on the track because the frequency responses differ. The hefty bass of the Ember certainly makes things sound more punchy.
When it comes to timbre the Ember is generally smooth, lush and warm with a dark tint. The S12 Ultra has a brighter, sharper, but also more neutral character.
CONCLUSION
The S12 Ultra is an excellent planar magnetic IEM for its price. The Ember costs nearly three times as much, making it hard to justify – if you’re on a budget.
That said, the Ember undeniably delivers more refined audio quality, with greater detail and nuance. It also offers a smoother, darker, and lusher sound signature, which may or may not suit you. I personally enjoy the Ember’s smooth and lush presentation. The only drawback for me is the bass quantity, as it can become too dominant on certain tracks. With EQ, this isn’t much of an issue, but otherwise it might be – unless you’re a real bass lover.
The S12 Ultra already has my warmest recommendations, and I stand by it wholeheartedly. The Ember is expensive, but between the two, I find myself reaching for it more often. It is the more technically capable, often by a significant margin — but not always.
Regardless, both IEMs are proof that single-driver planar magnetic earphones are part of the future, and Letshuoer is clearly keen on pushing the limits further. It’s a shame that only 999 units of the Ember will be produced, but I am confident the technology will make its way into future models – hopefully with a tad less bass quantity.
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