The End of a Saga

Ratings

Pros

• Sound iterated towards balanced, organic, smooth, warm, and natural musicality.
• Very good bass impact, with a powerful, deep, yet controlled, precise, fast, and very low decay physical presence.
• Slightly warm, musical, organic mids, with very good presence and fullness, detail, and informative capacity without becoming saturated.
• A more relaxed, less intense and somewhat more expansive soundstage within a size that highlights depth and a sense of stereo laterality.
• The most balanced and controlled treble of the entire series.
• More elegant, refined, and attractive design, with a beautiful finish on the Mocha version.
• Even the cable and its modular design have been improved, making it more compact and efficient.
• Very good level of accessories, including the DT01 Pro dongle.

Cons

• It’s not an analytical sound that breaks down every tiny detail.
• It’s not the most spacious, separate, airy, transparent, and vivid of sounds.
• It does not have the most extended treble compared to the competition.

Purchase Link

https://letshuoer.net/es/products/letshuoer-s12-ultra

Link to the WEB

https://letshuoer.net

Introduction

There is no doubt that the signature model of the LetShuoer brand is the S12, an excellent pair of flat magnetic IEM headphones. That is why it is normal for iterations and updates to be made to this model. At this time, the LetShuoer S12 Ultra, the latest model in the series, has been released, in which the brand has greatly refined its internal construction. Not only has the interior been improved, but the sound has also been refined across the entire audio spectrum to produce a naturally clear and truly immersive sound. Thanks to the deep customization and optimization of the drivers, the highs are delivered with clarity and detail. Overall, the sound is rich in nuance and perfectly balanced, providing a captivating and timeless high-fidelity audio experience. The new model retains the classic design of the S12, but with a new level of refinement. The S12 Ultra inherits the basic industrial design and features a redesigned housing around the female connector. The S12 Ultra is equipped with a 392-core silver-plated copper cable that offers excellent conductivity and high anti-interference performance. The new S12 Ultra comes with premium accessories, including the DT01 Pro DAC cable with 3.5mm SE output.
Next, we will analyze everything the brand says about its sound.

Specifications

• Driver Type: 14.8mm planar magnetic driver.
• Frequency Response: 20Hz〜40kHz.
• Sensitivity: 101dB.
• Impedance: 16Ω.
• Capsule Material: Aluminum Alloy.
• Jack Connector: Interchangeable 3.5mm SE and 4.4mm BAL with screw-on safety mechanism.
• Capsule Connection Type: 2-pin 0.78mm.
• Cable: 1.2m silver-plated copper with 392 cores.
• Available in two colors: Gunmetal Gray and Mocha.
• Starting price: $169.

Packaging

The LetShuoer S12 Ultra comes in a dark box measuring 156x106x51mm. The front features a pattern of shiny black triangles on a matte black background. The brand name appears in the lower left corner and the model name in the lower right corner, both written in gold ink. The back shows the features, brand and importer details, icons for the product’s certifications, and a sticker certifying its authenticity. When you remove the cardboard, you see a completely black box with only the brand name in the center and its slogan below in shiny black lettering. When you open the box, you can see several cards and, inside a black foam mold, the capsules. Underneath is the classic round black screw-top box with the brand name inscribed in the center. When you lift the lid, you can see a disc containing the silicone tips, and underneath are the cable with interchangeable connectors and the DAC cable. The complete summary of the contents is as follows:

• Two LetShuoer S12 Ultra capsules.
• Round, black, matte screw-top carrying case.
• Four-strand cable with 392 silver-plated copper cores and interchangeable 3.5mm SE and 4.4mm BAL plugs.
• One user manual.
• One warranty card.
• One small warranty certificate card.
• Three pairs of white silicone tips (Balanced) in sizes SxMxL.
• Three pairs of black silicone tips (Vocal) in sizes SxMxL.
• One DT01 Pro DAC dongle with cable and 3.5mm SE output.

As usual, the presentation is classic for the brand, with that round, dark, matte box, well protected with rubber inside. The cable is very interesting, and I think it’s great that the color matches the capsule. In my case, I chose the mocha color, which I find very attractive and elegant. But, in addition, for $169, LetShuoer includes its DT01 Pro DAC dongle with 3.5 mm SE output, which has an extra value of $16. The accessories offer very good value for money, considering the intrinsic value of the IEMS themselves.

Construction and Design

The LetShuoer S12 Ultra once again features an all-metal aluminum alloy construction, leaving aside the limited edition of 2024. This new version is available in two colors: gunmetal gray and mocha. I am very happy to have chosen the Mocha version, as it is very attractive and elegant.
There are no major differences in the external design. The shape is still based on the triangle on the outer face that extends beyond the sides to create very rounded curves at the edges. The surface piece containing the 0.78 mm 2-pin connection interface is no longer flat, but has a raised diagonal that divides the rectangle into two sloping triangles. Another difference is in the flat face of the connection interface: where there used to be a round hole, there is now a narrow rectangle, as in the 2024 version. The internal connection cables can be seen through this hole, and the letter indicating the channel is inscribed in white on the rounded end. The brand name remains on the edge; the first line shows the brand name in capital letters and the second line shows the model name. There is no longer a letter indicating the channel because it has been moved to the side of the connector.
The inner face is still very rounded and has a hole in the center, as in the other versions.
I don’t see any variation in the nozzles, either in size or diameter. The protection still consists of a perforated metal plate.
The most notable change to the capsules is on the outer face, as the triangle is now much more pronounced. Previously, it was not a triangle, but rather a drop of water. There is also a clear difference in the raised piece containing the connector, with a diagonal cut that divides it into two slanted triangles. These are small differences that enhance the design and make it more striking.
The surface of the capsule is still micro-sanded, slightly shiny, but without a mirror effect.
The cable is made of 392 strands of silver-plated monocrystalline copper, with four strands twisted together in pairs, and has two interchangeable connectors: SE 3.5 mm and BAL 4.4 mm. The color matches the earbuds. The plug has been reduced in size and the interchangeable connectors are pressure-fitted, although they are secured by a ring with an alternating triangular surface that has an internal thread. They have four gold-plated pins and a guide to facilitate fitting, as well as a white triangular mark to help align them. The removable part is completely cylindrical, has a thread on the edge, and the mark is inscribed in white lengthwise. The fixed part is also cylindrical and matches. The cable is protected at the outlet by transparent plastic. It includes a Velcro strap to gather the cable. The splitter piece is a smooth cylinder in the same blue color as the plug cover. It is 13 mm long and almost 8 mm in diameter. It has the same shape and appearance as the covers of the 2-pin 0.78 mm connectors. The plastic bases on which these pins sit are transparent and have a white letter inscribed on them to indicate the channel. At this end, the cable has a semi-rigid guide. Finally, the pin is a simple, small, cylindrical metal piece with a round hole inside through which the cables pass.
The cable is still modular, but includes two interchangeable plugs and has done away with the small 2.5 mm BAL plug, which is falling into disuse due to its fragility. The big change is in the new screw mechanism and the fact that the plugs are shorter in length.

Adjustment and Ergonomics

What remains unchanged, as far as I can see, is the internal shape, so the ergonomics are very similar. I still find the fit very good; there is minimal rotation inside the ear canal. The tips are somewhat short and do not vary, so there is not much else to say about them. The insertion is still superficial. The level of isolation remains the same, which will depend on the tips used. With my homemade foam-filled tips, they have a good level of seal and occlusion. The fit is simple, but may require some minor adjustments; even so, the feeling in the ear is very good. Both the surface and the rounded shape make contact and friction pleasant. Their small size also increases the level of comfort and ergonomics. They are comfortable to wear for hours, and I repeat that only the weight can be a minor inconvenience if you make quick or more sudden movements.

Sound

Profile

The first thing that came to mind when I tried out this new S12 Ultra was to compare it to the special 2024 version, as they are really very similar. The profile is the same, with subtle variations: slightly more emphasized sub-bass, cleaner mid-bass, a touch less high treble, a slight extra dose of mid-treble… Just subtle differences between the two frequency responses.
The S12 Ultra continues to move between my curves, which approximate my ideal frequency response (which I have not yet defined). It is a tiny w, where the maximum excitation is in the sub-bass, with that touch of 10 dB. However, the rest of the curve remains within a range of 7 dB up to 10 kHz, reinforcing the idea of a balanced and relatively homogeneous response. The planar brightness keeps the sound from feeling dark. On the other hand, I no longer detect as much density or a sense of a wall of sound, which makes the sound more balanced, as well as giving an impression of openness and expansion. The bass is still very powerful, but overall it has less punch.

Bass

I have to start again with the sound of the planar bass, because that’s where the real evolution lies. At first, its performance was a little different from the natural sound of good dynamic drivers, with a performance halfway between a dedicated BA transducer for bass and another dynamic transducer, which retained a certain duality of sound with a slight undulating/vibrating behavior. Now a positive step has been taken that brings it closer to realism by eliminating the audible oscillatory character that marred the performance of pure very low frequencies (20, 25, 30, and 40 Hz). In this case, the S12 Ultra plays the first audible note with a high physical load, a slight undulation that is not audible but is palpable, deep, and sensory. The second note is already practically canonical: powerful, dark, deep, dense, physical, and slightly oscillating. The speed of execution is evident in the last two notes, generating a marked rapidity that allows this vibration to be perceived. This generates a color that was not present in the first two notes. It is a very promising, very technical test, with an excellent start, truly dark, physical, sensory, and powerful. In real music, the result is a very compact bass, with quite a punch, dry, tight, very fast and with hardly any decay. The result is forceful, with a physical, dark, decisive and distinctive impact. This behavior is difficult to find in dynamic speakers and is the result of the evolution of the planar transducer, which improves with each new generation.
Being inclined towards the sub-bass, the low end is not overly voluminous or bloated. Thanks to its smooth texture and speed, there is not too much rumble, while the punch generates a big impact that lingers very briefly in the room; only that physical, dark sensation remains.
In the dirty, complex, and unfiltered bass test, this aspect is enhanced from 30 Hz onwards: the precision of the notes is very high and generates very fast lines that do not rumble too much, but are marked more by their darkness and physicality than by their texture, which is smooth and rigorous. The speed of the bass generates very well-defined layers, but they are brief and easily dissipate. Once again, a test that is surprisingly easy to perform, as if reproducing the worst bass were the easiest thing in the world. This gives an idea of the potential of the S12 Ultra when it comes to generating bass, its ability, technical capacity, resolution, and precision, but without forgetting that physical, dark, powerful, and deep part of its sub-bass. Without a doubt, it is an evolved planar bass.

Mids

The impression of clean mids persists in the face of bass frequencies sloping down from the sub-bass, with a low curve in the mid-bass and a bleed that tends towards zero. On the other hand, it is true that the first part of the mids is more traditional, with a concave descent instead of the flatness proposed by the META curve. Thus, this first half is less dense, more relaxed, and has a presence at one and a half, almost two, planes in its valley.
The sensation of silkier, more pleasant mids that are far from any analytical impression persists. The fact that the sound is not so dense and does not give the impression of being a wall of sound makes it somewhat more delicate and musical, and even more harmonious and refined.
The male voices have a physical base that is not too high and are somewhat further back from the main plane, although on occasions they step forward to demonstrate their harmonic complexity and ornamental richness. However, they fail to excite. Their outline is very good, quite rounded, without abrupt profiles, but with the brightness and sparkle necessary to generate a burst of energy when needed. The instrumentation in this first half supports the voices and is always appropriate to their position on the stage: if they should be in the background, they are placed there and only take center stage when necessary.
In a way, the mids have a relaxed expressiveness. The resolution capacity of the planars is high, but the S12 Ultra feels refined and rounded, generating a smooth and mellow response in which macro detail does not predominate, although the nuances are there.
The second half of the mids is more evident, more forward, with greater clarity and transparency, as well as more vigor, liveliness, and presence. Female voices are perceived as more prominent and closer. This makes their development more complex, complete, and detailed, but avoids unwanted sibilance. The roundness and delicacy of increasingly iterated highs to achieve the best tuning means that sibilance tends towards zero and that the upper mids have strength thanks to their base and richness rather than their brightness.
Thus, it could be said that the mids of the S12 Ultra have a warm, non-analytical, more musical, pleasant, and rich component, with a good impression of light and clarity, but with a more cohesive and continuous fluidity. They do not offer a wall of sound, but rather a more fluid, balanced, and even uniform presentation.

Treble

Once again, another twist on the treble of the S12 series. While the S12 2024 already had a more uniform sound and reduced energy, the Ultra now has a new redefinition that further balances the treble up to 10 kHz. After that, there is a slight drop compared to the special version, which makes it less extensive, although the difference is very small.
The amount of energy in the treble is relaxed, which allows the smoothness of the midrange to be preserved and keeps the shrillness at a pleasant and musical level. The high notes contain their edge and harmony; they feel subtle, elegantly bright, sparkling, and crisp, all with just the right amount of restraint. At no point is it a high range that could overwhelm Treble-Heads or those who enjoy sparkle and brightness. Without a doubt, these are very good trebles for an eminently warm and musical sound, especially coming from the planar trebles of the first S12s.
The Letshuoer S12 Ultra even achieves greater balance and homogeneity in the high range to sound more natural and organic, without sounding forced. In this way, the feeling of pleasant smoothness is preserved without sacrificing a certain realistic sparkle.

Soundstage, Separation

Without offering a wall-of-sound feel, the S12 Ultra even has a certain expansive character thanks to a more relaxed environment around its notes. It remains musically cohesive and smoothly balanced, but it lacks an expansive spark that prolongs and highlights nuances far beyond the base. The sound remains true to form, creating a sense of fluid, liquid music, in which the nuances are silky, without harsh or abrupt contours. The S12 Ultra has good detail, but its character avoids the breakdown of analytical macro and micro detail like other more technical systems. Thus, the micro-detail is described in a more diffuse way, in which the background is more cohesive and nuanced, with a certain dense character that prevents it from becoming too dark and separate. This musical continuity also prevents the feeling of separation and air from being too high, and the idea of a silkier, more pleasant and rounded character persists. Thus, the soundstage is once again presented as a seamless oval, with a clean and relatively transparent image, in which the recreation of layers and stratification are remarkable. Without a doubt, the S12 Ultra headphones are decisive, with fast transients and a precise, clear, concise, and spatially well-located sound, but they still maintain a certain intimacy in the soundstage.

Comparisons

7Hz Timeles II Flat Silver

With Flat Silver nozzles, the Timeless IIs closely resemble the S12 Ultras. They are practically identical up to 2 kHz. From there on, the differences are very subtle, with the greatest distance being in the mid and high frequencies, where the 7 Hz has more energy and air.
Planars imply energy, but the Timeless IIs are a little more sensitive and easier to move.
In the bass, as can be seen in the graphs, the similarity is tremendous. And this remains true in the very low frequency pure tone test. Very subtly, the S12s exhibit less vibration/wave behavior. There is a little more lift, energy, and impact, and even a little more dryness and speed. It is clear that the S12 Ultra has evolved from the S12 2024, as it now outperforms the Timeless II in the bass, which was one of the best to date. There is a little more energy, physicality, and punch, but without losing the technical aspect, as the S12 Ultra remains very effective, efficient, and precise. In fact, it is somewhat more concise than the Timeless II.
In the midrange, the Flat Silver nozzle penalizes the more airy and transparent sound of the Flat Gold nozzle. In this case, although the similarity is still very high, the S12 Ultra is more clearly perceived. Male voices sound cleaner and brighter on the S12 Ultra, while on the Timeless II there is a little more haze and darkness.
In the upper midrange, the S12 Ultra sounds slightly warmer, while the Timeless II seems to come alive with a little more light and brightness. In this range, the better extension of the treble begins to be noticeable, with more air, more harmonics, and more detail in the nuances.
Strangely enough, I still think that the Flat Silver nozzle does not favor the sound of the 7Hz, as the highs sound more nuanced than on the S12 Ultra. The LetShuoer has more sparkle, brightness, and naturalness than the Timeless II with Flat Silver. In the mid-treble range, there is a greater extension of energy, as well as more air in a clear way. However, the early treble is for the S12 Ultra.
The Timeless II’s open, analytical sound with a wider soundstage is trimmed with the Flat Silver nozzles. This brings it closer to the presentation of the S12 Ultra. However, it seems to have a little more depth and extension. It also seems to improve in terms of gaseousness and volatility. The S12 Ultra, with its greater warmth, is more musical and homogeneous. On the other hand, the S12 Ultra seems clearer and more precise than the Timeless II with the Flat Silver nozzles. The sound is more pronounced, better defined, and with slightly more resolution.
The level of detail is the same, and even the microdetail is expressed with the same clarity, although the sound presentation of each is not identical. The S12 Ultra is cleaner and more transparent than the Timeless II with Flat Silver, but that does not prevent the background microdetail from being lost in either. Are there any other differences? Yes, the Timeless II has four pairs of nozzles to expand the potential of its flat transducer. However, when it comes to potential, the Letshuoer S12 Ultra has even more to offer. It’s a shame they don’t have extra nozzles to prove it.

Conclusion

The Letshuoer S12 Ultra is the latest version of the Planar S12 series. It looks like it will be the last model in this famous series, which has been perfected since its first version. The S12, S12 Pro, S12 2024, and finally S12 Ultra models bring to a close a highly successful series of 14.8 mm magnetic planar transducers. Without a doubt, the S12 Ultra is the crowning glory of this collection. The Letshuoer S12 Ultra is possibly the IEMS of this type with the best value for money and sound quality. It is a safe bet in two colors: the classic Gunmetal Gray and the new and attractive Mocha. With a slight but successful aesthetic tweak to its design, the Ultra gives an external idea of its internal refinement. They continue to feature a large modular cable, now more practical, compact, and secure thanks to its screw mechanism, in addition to the classic matte black round case with protective rubber inside. In addition, Letshuoer includes the DT01 Pro dongle with 3.5 mm SE output in this edition, priced at $16. Most importantly, their sound demonstrates the refinement acquired over the years, with balanced and iterated highs to ensure a full, pleasant, and enjoyable listening experience, moving away from the initial presentation of the S12 model. Without a doubt, Letshuoer’s advances have been forward-looking in search of the best balance in the high range, which was already achieved with the 2024 version and has been realized here with the best implementation. Of course, the bass has also improved its performance at very low frequencies and is now more natural, precise, contained, dry, and smooth in texture, yet powerful and physical in its punch. This is a very dangerous approach to the best dynamic transducers, but with all the technical advantages of a flat driver: control, speed, and minimal decay. Finally, the midrange moves away from the feeling of a wall of sound and density in the foreground to maintain a certain warmth and sound very musical, organic, natural, pleasant, even smooth and balanced, but above all, mature and refined.
The Letshuoer S12 Ultra is a Mocha-plated finishing touch that will immediately become a classic.

Sources Used During the Analysis

• NiceHCK Octave.
• iFi GO bar Kensei.
• EPZ TP50.
• Burson Audio Playmate 2.
• Aune X8 XVIII Magic DAC + OpAmp Sparkos Labs SS3602 + Aune ND7.
• Hidizs AP80 PRO MAX.