LETSHUOER S12 Review 23


LETSHUOER S12 Review – New King of Planar IEMs

LETSHUOER has announced the S12 Planar IEM back at the end of 2021. Designed with a minimalistic design, the S12 packs a custom-developed 14.8mm large planar magnetic driver inside. It features aluminum alloy shells crafted using a complicated CNC machining process. The S12 comes in two different color options, Nebula Grey and Frosted Silver.

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Nebula Grey colour

LETSHUOER S12 comes packed with a high-purity silver-plated monocrystalline copper cable. This cable has 2-pin 0.78mm connectors. Customers can choose between 3.5mm single-ended and 4.4mm balanced connectors while ordering the S12.

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One of the best stock cables you can find in the 150-200$ price range

What’s in the box

  • S12 IEMs
  • Documentation (user manual etc)
  • Faux-leather zippered case
  • 3x pairs of foam tips
  • 6x pairs of silicone tips
  • 2-pin 0.78mm stock cable


  • Full-size 14.8mm planar magnetic driver.
  • Minimalistic design.
  • CNC machined aluminum alloy cavities.
  • High-purity silver-plated Monocrystalline copper cable (available in 3.5mm and 4.4 mm termination options).
  • Available in two color options, Nebula Grey and Frosted Silver.


  • Impedance: 16Ω±1%.
  • Frequency Response: 20Hz-20kHz.
  • Distortion: 0.5%±0.1%.
  • Price: 143.65$

I would like to thank LETSHUOER for providing me with the review sample of S12 (no affiliate link).

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S12 FR Graph

Out of the box, the S12 has a warm and smooth sound signature emphasized by an excellent bass extension and a full-bodied overall presentation. Complex passages maintain top-notch detail and bass texture on fast-paced EDM, Pop, and Rock tracks is still very enjoyable. The signature of the S12 is mildly V-shaped with a strong focus in the sub-bass rather than the mid-bass. There’s a satisfying rumble in the low end. Rumble comes through well-articulated while percussive beats are clean and well-defined with almost zero smearing despite its emphasis.

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Despite the large 14.8mm driver inside the shells are perfectly ergonomic and comfortable in the ear


The S12 has an elevated bass response with the boost becoming more apparent in the sub-bass region at around 50 Hz which is sustained until around 150 Hz before gradually dipping. The drop past 150 Hz is not drastic and uneven so, despite the apparent sub-bass bias, the low-end maintains a fairly balanced presentation with an organic timbre. Decay, meanwhile, is relatively pacey allowing uptempo music to shine without losing any detail. One thing I find noteworthy is how good the bass texture is on the S12. You could hear the separation of the bass guitar and the kick drums even on intricate tracks. While there is an obvious boost in the low end, its rumble and punch are well-controlled without sounding boomy.

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The interesting placed air pressure hole has a filter inside


The dip starting in the midbass is sustained through the lower midrange of the S12. Despite the mildly recessed lower mids, there is a smooth transition in the frequencies thus avoiding any odd and unnatural harmonics. With the upper midrange bias, stringed instruments, as well as vocals on higher octaves, get more emphasis. The lower midrange, however, is neither overly recessed nor thin-sounding due to the power from the boosted sub-bass region. While there is top-notch clarity and a fairly transparent midrange, its lower registers lack the presence which in turn takes away just a little of body and weight on snares and other percussions.

Nonetheless, the midrange of S12 remains transparent and open-sounding while providing a good level of attack. The lower midrange is tuned with a recession, increasing clarity and definition though not as strong with male vocals as it is with female vocals. Strengths include percussion, woodwinds, and plucked strings, not as strong with male vocals, bowed strings, and brass but still enough to at least be considered a general all-rounder. S12 can achieve superb separation on the vocals, the upper midrange spike provides more clarity and presence on high-pitched vocals compared to the low-pitched ones which are pushed back just a little bit. Listening to the acoustic guitars, high notes on the chords are more highlighted but the low-pitched strings still manage to maintain satisfactory weight and body even with the slight lower-midrange roll-off.

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S12 has a pleasing sparkle that manages to keep harshness at bay while there’s also some ample air which contributes to an open sound as well as a huge headroom. The mild boost in the brilliance region provides an added resolution and clarity to the overall presentation and despite the slight lift, there is no tinge of metallic timbre to the sound. Treble is one of the best that I’ve heard in a long time. Well-extended and smooth, whilst conveying enough energy for sparkle. Transients are extremely snappy, resulting in zero splashiness or overlap. The treble boasts excellent extension adding clarity and air to the overall presentation. The overall timbre of S12 keeps everything fairly natural even with the boost in its bass and treble.

Detail retrieval, meanwhile, is excellent as it can produce even the tiniest detail with no effort. Decay is relatively fast which contributes to an organic timbre even with the minor dips and spikes across the treble region. Guitar effects and synths were performed with excellent detail and attack. Guitar solos where you’d get an energetic and lively treble presentation, also a satiating treble bite with no hint of harshness in its cymbals and high-pitched guitar riffs.

Saying that I want to add that my testing is done using Cayin Ru6 DAC-AMP and wide-bore Spinfit ear tips. Depending on your source and tip choice your experience may vary in the sound including the treble.

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The S12 boasts a very expansive soundstage even out of the box. The extended treble improves instrument separation. The staging provides a fairly out-of-your-head experience with an enjoyable 3D feel to it. Overall, I’d say this is one of the best instrument separation and layering that I’ve heard in this price range.

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Besides the sound performance, I also liked the whole package with the LETSHUOER S12. The included cable is one of the best stock cables with a perfect thickness that doesn’t tangle, is also soft enough, and stays firm as you put it down. The connectors are the same color as the IEMs which I always admire and you don’t get it very often in other brands. The craftsmanship of the metal parts, including the shell, is also top-notch which is not much evident in online product photos. All these add more value to the S12 in my opinion, especially if you are obsessed with these details like me. Adding the well-tuned planar sound to the math, you guessed it right. The S12 certainly deserves your attention if you have the budget.