Letshuoer S12 and S12 PRO are famous for the excellent implementation of a planar magnetic driver. They both have a U-shaped sound signature with fast and tight planar bass, lots of dynamics, and a very resolving treble.
Both IEMs feature a 14.8mm Planar magnetic Driver, all-aluminum CNC machined housings, and de-attachable cable. In addition, the S12 PRO comes in a new color scheme, it has a different nozzle filter that affects the tuning, and it also comes with a different modular cable. But before we dive into more details, let’s first start with the unboxing. Both IEMs come in stylish medium-sized boxes. The differences between the boxes are minor. The contents of the box are almost similar for both models and they include:
I would like to thank Letshuoer for providing the samples for this review. I am not paid to make this review or offer any specific opinions. All thoughts expressed in this review are my own.
In the box:
- The IEMs
- 1.2 meter-long de-detachable cable
- 6 pairs of silicone ear tips (including three pairs of so-called balanced tips)
- 3 pairs of foam ear tips which come with their own storage box
- A nice carrying case
- Warranty card
- QC and contact card
- And product catalog
The impedance of both pairs is 16 Ω and the sensitivity is 102 dB.
The main difference in here t is that the Letshuoer S12 cable comes either with 3.5 or 4.4mm connector termination, while the S12 Pro comes with a modular cable with interchangeable connectors. Of course, the connectors are also included. Another difference is in the balanced ear tip color, which is different for S12 and S12 pro. The rest of the accessories are the same.
Design and build
Letshuoer S12 comes in two colors, Nebula Grey and Frosted Silver. The S12 sample in my review is Frosted Silver. S12 PRO on the other hand comes only in just one color and that’s blue. If you ask me, the best-looking one of the bunch is still the Nebula Grey.
The shells have a minimalist appearance and are made out of aluminum alloy that is CNC machined. The faceplates are matte and there is a small square section with silver edges that sticks out of the faceplate. Despite having quite an unusual triangular type of shape, the S12 really stands out in the ocean of IEMs and is surprisingly ergonomic too. The shells are also lightweight and well polished so finding a comfortable fit should not be a problem at all.
The shells have one vent hole located on the inner side of the shell. The nozzles are also made from aluminum alloy, and according to the manual, they are 5.9mm in diameter. There is also a metal mesh at the end of the nozzle, and a lip that helps to retain the ear tips. The nozzles are of a shorter size and might cause some fitting problems for some ears.
The main differences in the build between Letshuoer S12 and S12 PRO are the shell color, filter type, and nozzle mesh type. The latter difference can be seen with the naked eye. Overall, I liked the minimalist look of both IEMs, it’s not only aesthetically pleasing but also practical and durable.
Fit and comfort
I spent quite a lot of time with both pairs and in most scenarios, they were comfortable with no differences between the models. The IEM shells are well-polished and there are no sharp edges here. In addition, the finish is matte and it resists the fingerprints well.
The Letshuoer S12 and S12 PRO shells are equal in size and can be described as medium-sized shells that have a very natural and ergonomic shape. In my case the fit was good, but if you have very small ears, you may struggle with a fit. But I need to point out that due to the shorter nozzle, the fit can still be challenging for some people, especially with stock ear tips. I myself had to do some tip rolling before I found a couple of ear tip pairs that really helped me to achieve a good fit & seal. But again, I have large ears and quite a wide opening of the ear canal, so your mileage may vary.
I’ve been using both IEMs for extended periods and I would say that the fit was acceptable. This was especially rrue with the tips rolling. In terms of passive noise isolation, the performance was good. And while neither S12 nor S12 PRO provide a class-leading isolation, it still was effective at blocking out most of the outside noise.
Cable
Now let’s look at the cables and that’s where the significant accessory difference between the models lies.
The Letshuoer S12 can be ordered either with a 3.5 or 4.4mm cable. While the S12 Pro comes with a modular cable that has interchangeable connectors. Letshouoer also included all three connector types with S12 PRO – the 2.5mm balanced, 3.5mm single-ended, and 4.4mm balanced. On the other end of both cables, we have 0.78mm 2-pin connectors.
All connectors on both cables are gold-plated. White there is no typical L and R channel marking on the connectors, the bases of the right 0.78mm connector are red in color, so this helps with channel navigation. The cable has a metal splitter and soft pre-molded ear hooks. Overall I liked both cables that come with these IEM and I especially liked the modular cable that is included with S12 PRO. It takes seconds to interchange the connectors, and it gives a lot of flexibility to the listener.
Letshuoer S12 and S12 PRO sound overview
First of all please note that all the sound impressions I’m sharing on this channel are completely subjective. Please take them with a grain of salt. Before throwing my main DACs and amps in the game I always use my old and trusted Galaxy S10 phone. With S12 and S12 PRO, I’m happy to report that my phone didn’t have enough power to make them shine.
The impedance of both pairs is 16 Ω. But they are still not very efficient rated at 102 dB, so at least a basic DAC/amp is highly recommended. It’s also important to mention that the Letshuoer S12 PRO uses a different nozzle filter that affects the tuning. I will be breaking down the difference between the models as we talk about frequency response further in this review.
Bass
As usual, we will start with the bass. Planar magnetic drivers are one of the main selling points of Letshuoer S12 and S12 Pro and I think this IEM has one of the best implementations of micro planar drivers we currently have on the market.
The bass is well-controlled, tight, fast, and well-extended. The mid-bass is more dominant on this pair and you should not expect too much sub-bass rumble here. But this is a type of bass I call complimentary, it’s always there when you need it, but it’s never bloated or muddy.
The bass is quite informative and detailed too. The whole bass range sounds good, and the tracks that have a lot going on in the lower register don’t sound muddy, which is good. But if you are a bass-head, you need to look elsewhere, as even with EQ, this IEM is not near any bass-head levels.
The main difference between Letshuoer S12 and S12 Pro in this department is that S12 Pro has a more pronounced bass, especially the sub-bass region. The difference is just a few dB, but it’s enough to make an audible change, especially when you compare them against each other.
I personally preferred the bass on the Letshuoer S12 PRO as in my opinion it compliments the overall tuning of this IEM better.
Midrange
The midrange is transparent and offers a good level of texture, detail, and resolution. But despite its character, it’s not the most upfront midrange. There is some bass bleed into mids, the lower midrange is full and lush, and it has a good note weight, which is especially audible on male vocals.
The upper midrange is detailed, energetic, and intense, and it was borderline sibilant and harsh for me on S12, especially with female vocals. With Letshuoer S12 Pro the situation was much better.
The midrange brings a lot of details, but it sounded not very musical, and a bit clinical, though I think those who love analytical sound signatures will find the midrange here pleasing.
At the same time, IEM performs really well in terms of instrument placement and separation and if we put musicality aside, the midrange sounds very informative, though it still takes a back seat due to the overall tuning of S12 and S12 PRO.
The main difference between the models in this part of the frequency response lies down in the upper treble. The upper treble is less pronounced on Letshuoer S12 PRO, making it a bit smoother. As far as I understood this was achieved by a different filter and nozzle. As per my playlist, I personally enjoyed the midrange on S12 PRO a bit more, though the upper midrange on S12 is more crisp.
Treble
The treble is the star of the show here. It’s got a great extension, energy, and sparkle, but lacks some air. Prior to testing Letshuoer S12 and S12 PRO, I heard some complaints about metallic timbre and brightness of S12 in the audio community, but in my case the timbre was accurate. Though the brightness is there, and if you are a treble-sensitive person, both S12 and S12 PRO can be a bit irritating, but again, in this case, I think the upper mid-range might not suit your tastes as well.
The whole treble region resonates with clarity, but as I already mentioned it lacks a bit of air. Most elements stand out with distinct precision and impact. The treble also got a good amount of energy, offering a crisp rendering of the details and nuances.
Micro details are excellent for this price bracket, and with well-recorded music, the Letshuoer S12 and S12 PRO treble reveals itself as exceptionally detailed and transparent.
The differences in treble between Letshuoer S12 and S12 PRO are subtle and treble on S12 PRO is slightly less energetic. This paired with the less pronounced upper midrange creates an overall smoother presentation.
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Sound stage, imaging, details
Now to the sound stage. The Letshuoer S12 soundstage is above average in width, but not very deep or tall and there is no difference in sound stage size between S12 and S12 PRO.
The sounds on both IEMs hold their particular positions in space and imaging is also good.
The separation of instruments and detail retrieval is what sets S12 and S12 PRO apart from most of the competition in this price bracket.
The separation of instruments is great, and I had no problems identifying the sounds even during busy passages. The same situation is with detail and micro-detail retrieval both of which are impressive to see at this price range.
Both Letshuoer S12 and S12 PRO are good at extracting small details and nuances out of your recordings and the resolution of these IEMs is impressive as well. The layering and clarity are also good, and both IEMs are quite on the technical side. Still, I would give an S12 a slight edge in this department, as to me it sounds more clinical, and analytical, and provides a tad more details, but it’s very subjective, so your mileage may vary.
Conclusions
At the time of making this review, I spent more than 1 month with S12 and S12 PRO, and during this period these two were my go-to IEMs for music, office, and gaming.
Both IEMs are very good value for the money, and you should choose one over another solely based on your sound preferences.
Pros:
- Distinctive design and all-aluminum alloy shells
- Engaging U-shaped sound signature
- Well-controlled, fast, and detailed bass
- Crispy treble extension with lots of energy and sparkle
- Great instrument separation
- Excellent detail and micro detail retrieval
- Good technical abilities for the price
- Great cable (especially the modular one that comes with S12 PRO)
- A good set of accessories
- And a carrying case
Cons:
- The upper midrange is borderline sibilant (especially on S12)
- The midrange is slightly recessed on both IEMs
- And both IEMs sound a bit clinical on occasions
Letshuoer S12 and S12 PRO are stand-out pairs in their price bracket and as I mentioned, you should choose one over another based on your sound preference. Modular cable should still be considered as a bonus, and honestly should not be taken into consideration when you make a final choice between these two.
I personally enjoyed the sound of the Letshuoer S12 PRO more as to me it sounds more refined, musical, and engaging, but overall I can absolutely recommend both IEMs to those, who seek a technical, analytical yet fun-sounding pair of in-ear monitors at this price bracket and need a fast bass, good instrument separation, and a crisp treble.
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