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Disclaimer: The 64 Audio U12 was provided to me as a loaner by 64 Audio for the purpose of this review. This will in no way affect the review whatsoever. This review, as always, will be objective and reflect my honest thoughts and opinions on it.
I would like to firstly thank Vlad of 64 Audio for loaning the U12s to me to review. I met Vlad at CanJam Singapore 2017, and after talking to him for a period of time regarding ADEL and apex, as well as tia, I introduced myself and showed him my previous review. After expressing interest in reviewing 64 Audio’s IEMs, he agreed and things just fell into place.
I really appreciate the support that Vlad and 64 Audio has given me, considering I only have 1 previous review under my belt. With that being said, objectivity is still at the core of my reviews, and will always be. This review is no exception.
Again,
please bear with me. This is yet another rather lengthy review, as I would like to leave no stone unturned and be very detailed as to portray as accurately as possible to you – the reader – the overall sound profile as well as the benefits and sacrifices that apex brings to the table. There will also be a comprehensive comparison between ADEL and apex as part of this review.
All of the pictures in this review was taken by me, if you guys need to use them for whatever purpose, do let me know and link this review. I hate to put watermarks on my images so this is greatly appreciated!
As always, this is just my second review; any feedback would be welcomed! I decided to change things up a little for this review and be a little more comprehensive in my comparisons. Do let me know how did that go! Huge thank you to everyone for the support!
TL;DR
Pros:
Decent isolation, Comfortable form factor, Satisfying and visceral bass, Extremely musical, Smooth and easy to listen to
Cons:
Limited tips provided, Sound signature not for everyone, Warmth doesn’t play nice with slower genres
64 Audio was initially known as 1964 Ears prior to their (now defunct) partnership with Asius Technologies. They have an impressive clientele which includes Beyonce and Seal, just to name a few. They have recently announced 2 new Flagship IEMs which utilizes the TIA technology. Also, known as Tubeless In-ear Audio, tia involves a completely tubeless system using the newly developed tia driver, which unlike typical balanced armature driver design, does not have a tube where the sound will come out of, but rather the driver itself is completely open.
The tia Fourte is the first in-ear monitor in the world to fully utilize the tia technology and the A18 Tzar is the first 18-driver in-ear monitor in the world, a testament to 64 Audio’s commitment to innovation and technological advancement.
With that said, 64 Audio has a rather impressive line-up, starting from the A2e for the budget-conscious to the state-of-the-art tia Fourte for those who demand the absolute best, 64 Audio has something for everyone.
U12
Prior to the launch and release of the tia Fourte and the A18 Tzar, the U12 was the universal variant of 64 Audio’s previous flagship, the A12.
The universal U-series was intended for consumers and musicians who does not want to go through the trouble and the process of getting a custom in-ear monitor but still demand high audio-fidelity from their earphones.
In lieu of the recently launched tia Fourte and the A18 Tzar, it would be interesting to see how the U12 stands up against them and with new IEMs being launched every other week, it would be interesting to see the U12’s performance in such a competitive market.
Unboxing
The unboxing experience on the U12s was very well thought out. The box itself was surprisingly small and consists of 2 parts.
There is the outer sleeve, which is white and the front has the 64 Audio logo with a picture of a set of their U-Series IEMs with the bottom stating just that. The front is flanked by 64 Audio’s tagline, “hear everything” on both sides.
The back has the history of 64 Audio shown on it as well as a short introduction to the apex technology. Below that shows the content of the box as well as other miscellaneous information.
Removing the sleeve reveals a red box with a rather epic picture of an artist on the top with the 64 Audio tagline yet again on the bottom.
Opening up the flap will reveal the content of the box. 64 Audio has also cleverly placed the quick start guide at the back of the flap rather than including a card or booklet. The top tray houses the dehumidifier as well as the tips. Below that is the case and in it, the IEMs themselves. 64 Audio also has included a sticker.
Accessories
64 Audio U12
64 Audio IEM Case
Shirt Clip
Cleaning Tool
Dehumidifier
1 set of Dual Flange Silicone Tips
3 sets of Comply Foam Tips (S,M,L)
64 Audio Sticker
While not as comprehensive as the Empire Ears accessories package, the accessories that 64 Audio includes with the U12 is no slouch either. One item in particular that stands out to me is the dehumidifier. Not a lot of IEM companies includes them in their accessories package and I usually have to get mine from shoe boxes or purchase them separately, so it’s nice that 64 Audio has decided to include them.
If there is something that I found disappointing about the accessories is the provided tips. For a product of this price and considering how it was the Flagship IEM from 64 Audio, the tips that were included were rather disappointing. It’s no deal-breaker, but I would’ve preferred them to at least include a set of regular silicone tips in small, medium, and large size.
However, I would like to take this moment to express how well thought out the 64 Audio case is. It is small, compact and it is very practical. It is even smaller than the Pelican 1010!
In the case, there is a cut out for the provided dehumidifier, the cleaning tool, and shirt clip, there are even slots for 2 extra pairs of apex modules! The slots that house the IEMs are also very well thought out. It is lined with rubber to protect the IEMs themselves from any impact or shock, and there is a pop-up slot for cable winding and 4 slots for placing the 3.5mm jack in.
Here’s the thing, no matter how I winded my stock cable, I always found the jack to line up perfectly to 1 of the 4 slots for the jack and although it is something very minor, it shows how much thought 64 Audio put into designing this case.
However, this case might be too small if you are planning to swap the stock cable out for an upgrade cable.
Construction and Finish
The U12s are made of plastic, which is normal and rather common in universal IEMs. However, 64 Audio opted for a more subdued and simple design. The entire IEM is glossy black with the 64 Audio logo and the port for the apex modules on the faceplate.
While some may argue that the design may be too plain and simple for an IEM of its price, personally I think it’s fine. The minimalistic looks give it a sense of class; the glossy black is reminiscent to a grand piano. The surface does, however, attract fingerprints, but since it is black, it is not really noticeable.
The IEM itself is very solidly built and does not feel cheap. The review loaner I received has no imperfections on the shell either.
The shell is rather small too, unlike other 12-driver IEMs like the Layla 2. It is quite amazing how 64 Audio managed to fit 12 drivers into such a small shell, and not to mention the slot for the apex module as well.
Fit
The small shell is rather ergonomic, and I achieved a good fit very easily. With that said, as the U12s are a universal set of in-ear monitors, the fit of the U12s are highly dependent on the tips, and as I have mentioned above, the tip selection that is provided with the U12s are less than stellar, which might be a problem for some.
Personally, I find the final audio tips that were given out during CanJam Singapore to work best for me, with the SpinFits coming to a very close second.
Tip Rolling
As tips are an integral aspect of every universal fit in-ear monitors, I decided to include a section on tip rolling, as I do believe that the choice of tips does change the sound slightly.
Final Audio Tips
The Final Audio tips are by far my favorite tips to use with the U12s, period. They are extremely comfortable and provide a very clear sound without dampening any treble or over-emphasizing the bass response.
Verdict: Highly Recommended
SpinFits
The SpinFits fit extremely well as well. They are comfortable but I do find them to “push” the IEM out of my ear canal after some time of use, and I would have to push them back into my ears. However, they too, provide a very clear sound very much like the Final Audio tips.
Verdict: Highly Recommended.
Spiral Dots
The Spiral Dots are technically incompatible with the U12s as the nozzle is too long and the tip of the nozzle will peek out of the ear tips when inserted all the way, which can cause pain during usage.
A popular workaround would be to use O-rings or to cut the stem of another pair of tips then inserting that before inserting the Spiral Dots. Personally, I tried that but that resulted in the tips popping out of the nozzle when removing the IEM and getting stuck in my ear canal.
In terms of sound, they reduce bass and accentuate the treble slightly. However, getting the tips to fit onto the nozzle is too much of a hassle in my opinion and thus, I would not recommend them.
Verdict: Not Recommended
Comply Foam Tips
The Comply foam tips are provided together with the U12s in 3 sizes; I used the medium size. They are extremely comfortable and fit very well.
However, they do dampen the treble and increase the bass response which I feel would not benefit the U12s due to its sound signature (more on that later on). But they
are very comfortable and fits very well so I will still recommend them.
Verdict: Recommended
Stock Dual Flange Tips
The stock dual flange tips are relatively comfortable, but they do irritate my ears slightly as I am not used to using dual flange tips. In terms of sound, they provide a slightly reduced bass response. Overall, I would recommend these tips over the Comply Foam Tips.
Verdict: Recommended
Sound
Do note that the section on sound is written based off the U12s with the stock cable using the default M20 module running out of an AK380 with primarily lossless FLAC files and some 320kbps MP3 files.
I would like to thank Calvin of Music Sanctuary for loaning me the Astell&Kern AK380 + Amp. One feedback that I received and an aspect of my previous review that I was not satisfied with from my previous review was my poor sources. And so, Calvin has very graciously loaned me a set of the AK380 + Amp to aid in improving the quality of my reviews.
Soundstage
The soundstage on the U12s is very wide and spacious. This is without a doubt, partly due to the apex technology. The soundstage is also extremely holographic; instrument placement is distinct and well defined.
While the soundstage is wide and spacious, the overall sound is still rather intimate and upfront. This is unlike my experience with ADEL in-ear monitors, as they have a rather distant overall sound. The U12s however, do still have a very immersive soundstage presentation, putting the band right in front of you; and it’s easy to get lost in the music.
Bass
The bass on the U12 is probably the most prominent and outstanding aspect of the sound signature. The bass has rumble and authority, it is punchy and has great depth. Bass impact, however, is not very impactful and you won’t get the “slam” that you can sometimes feel in your eardrums when using IEMs with a stronger bass presence, and my guess is that this can be attributed to APEX.
Therefore, while the bass is strong, I would not call the U12 a “bass head IEM” as it just does not have that slam and soul-shattering impact. It also does not have enough presence and authority to be classified as a bass head IEM as well.
Attack and decay is impressive as well; it is not extremely fast nor is it slow, it is just right which gives a very natural presentation of the bass, not overly energetic or sluggish. Still, it manages to keep up with a lot of fast tracks with ease.
The Sub-bass is
very well articulated and depth and texture is incredible. It is as authoritative as the bass but sometimes, it can bleed into the mid-range.
One of my favorite test tracks for bass is
Gooey by Glass Animals. As mentioned above, while the bass impact is not extraordinary, the details in the reverberation, as well as the articulation, is outstanding; I could hear the “airiness” in the reverberation and the bass sounds very natural.
Midrange
The midrange on the U12 is of a warm tonality. Although they are not forward, the mids sound very intimate and sweet. The most prominent factor of the midrange is how smooth and lush they sound. In fact, the U12s have one of the smoothest midrange that I have heard in an IEM, albeit, that number isn’t staggering.
Because of the smoothness and lush of the midrange, coupled with its warmth, the U12s is a very musical piece. However, this comes with a trade-off that is the resolution. The U12s are not the most resolving piece, which may be a deal-breaker for some, however, the musicality of this IEM is extremely outstanding.
I really like the vocals on the U12s. When I listen to
Happier from Ed Sheeran’s
Divide, vocals sounded extremely sweet and intimate; it is as if Ed Sheeran was singing right in front of me. Overall, the mids sound very personal and intimate; sweet, smooth and very easy to listen to.
However, just like the Empire Ears Athena, I personally feel that the midrange is too warm for classical or piano music. They will still sound good, but I do feel that they will sound a tad unnatural.
Treble
The treble is the most polarizing aspect of the U12’s sound signature. I have had people who tried the U12s complain about how subdued and rolled off the treble sounded to them and on the other hand, I’ve had people who were extremely satisfied with the treble, describing it to have “just the right amount of sparkle”.
I feel that the treble on the U12s is an acquired taste. Some airtime with the U12s is needed to fully understand and appreciate the treble. While the treble is not very extended, they are not rolled off per se. With that said, the treble does have a very natural tonality.
The treble is not sharp, and I highly doubt anyone would think of them as sibilant. There is a very nice sparkle to it, and it is fast enough to keep up with most genres. They are a little softened and smooth; which adds on to the musical signature of the U12s.
While the separation and micro-detailing are not as transparent and clear as some other monitors such as the Empire Ears Zeus, nor is the extension particularly outstanding, they do have a certain airiness and smoothness in the treble, which is actually rather pleasing.
There is also a certain degree of resolution to the treble. It is not the most resolving but it is definitely no slouch as well. The cymbal clashes in
Back in Black by AC/DC are very clear and very nicely articulated.
Overall Signature
Overall, the U12s have a very musical signature and it is very enjoyable and easy to listen to. There is an aspect of “fun” in the sound signature. The U12 is a very versatile IEM with its warmth, authoritative and powerful bass, coupled with the smoothness of the overall sound signature. It plays very well with almost all genres, with slower music being the exception. I feel that some forms of acoustic as well as classical or orchestral music do tend to sound a tad unnatural because of the warmth of the U12s. Don’t get me wrong, they still sound excellent, just a little unnatural.
With that said, the U12s are very intimate sounding; the sound is upfront and personal. I really enjoyed listening to vocals especially on the U12s as they sound extremely sweet and with the intimacy of the sound signature, it is as if the artist is performing in the very same room. Genres that excels for the U12s, in particular, is Rock, Pop, and EDM. With the visceral bass and the warmth of the U12s, they really bring out the energy and life of the said genres.
While not the most resolving monitor out on the market, the U12s have a very musical sound signature that is very forgiving. It's softened and slightly distant treble and visceral bass response is not for everyone out there, but for those who enjoys a more musical sound will definitely enjoy the U12s plenty.
Sources
The U12s are very forgiving to both sources and recordings. It sounded extremely pleasing out of my iPhone running Spotify Premium but the U12s will also scale very well with better sources and recordings. IT will also benefit from additional power. I always prefer the U12s on the AK380 + Amp versus the AK380 alone. The added power of the AK380 Amp really opens up the sound giving it better imaging and resolution.
Apex
Apex is a 64 Audio in-house technology that ships with every 64 Audio IEM apart from the tia Fourte. The principle is simple; using a pneumatically interactive vent, apex relieves pneumatic pressure in the ear, providing a more open soundstage while reducing ear fatigue. Apex also allows the varying of isolation levels for different sound flavors.
Currently, there are only 2 different types of apex modules that are available on the market: the M20 and M15.
M20 vs M15
The M20 provides more isolation than the M15, having 20db of isolation versus 15db, hence the names M20 and M15. While not up to the level of custom in-ear monitors, I found the M20 to have excellent isolation, at least as good as most of the universal in-ear monitors on the market. However, the 15db is not bad either. Generally, I don’t really hear much of the ambient noise with both modules.
In terms of sound, the M20s has a smaller and less open soundstage than the M15s. Bass response is stronger and more visceral and authoritative on the M20s.
However, with the M15s, vice versa to the M20s, have a wider, more open soundstage. Bass response is more controlled and sub-bass no longer bleeds into the mid-range. Resolution is also better as the bass is now more controlled, and it is now easier to hear all of the finer details. Also, due to the lowered bass response, the U12s do sound a little brighter relative to the M20.
Personally, I highly prefer the M15s as they control the bass and give the U12 a more open sound.
Apex vs ADEL
I would like to thank Calvin of Music Sanctuary yet again, for loaning me a universal demo unit of the A12s that is able to fit ADEL modules for the purpose of this comparison.
Here is where things get interesting. In principle, both apex and ADEL is out to achieve the same thing: a more natural and open sound while reducing ear fatigue. ADEL goes further and states that with ADEL, you will get a higher perceived volume and thus, will listen to a lower volume level and by extension, save your hearing.
ADEL uses a membrane that will absorb pneumatic pressure in the ear canal when listening to music. Meanwhile, apex uses a special type of foam that “activates” when pneumatic pressure is present, and then venting the said pneumatic pressure.
Ever since getting my Empire Ears Athena-VIII ADEL, I have been interested in comparing the differences between apex and ADEL as I could not find any detailed comparison between the both.
And I believe many of those who are still on the ADEL 64 Audio IEMs would be interested in seeing how they compare as well as is it worth it to upgrade to the new apex modules.
With that said, the comparison is still done on the U12s, in which I will make reference to the U12 sound signature. This comparison is most valid for the U12s and might not apply to the other models but I do hope that it might give you a general idea of the differences between the apex and ADEL modules.
Isolation
Without a doubt, the apex modules have superior isolation to the ADEL modules. Specifications of isolation levels on paper aside, I never heard ambient noise on the apex modules that I do on the ADEL modules.
Like I mentioned in my Empire Ears Athena ADEL review, isolation is sub-par when using the ADEL technology. In fact, the isolation is so poor that even with one of the touted ADEL benefits being higher perceived volume, I found myself to be turning the volume up even further to compensate for the loss in isolation.
Ear Fatigue
There is this controversy that I saw on the 64 Audio thread while I was doing some research for this review regarding the effectiveness of apex.
Personally, I care less for claims and specifications that have been made on paper and I care more about my personal experience. Personally, I have issues with ear fatigue and IEMs. I would get ear fatigue after listening for an hour and I would need to remove the IEMs in order to rest my ears before continuing.
When using the ADEL modules on the U12s, like my experience with my Athena ADEL, I do not get any ear fatigue whatsoever. I am able to use the U12s for hours on end.
Now, here comes the part where some of you might disagree with me: I get the same experience with apex. When I use apex, I do not get that ear fatigue that I am so familiar with. Therefore, in my opinion, and in my usage, apex works as well as ADEL.
As always, YMMV and what I experience may not be the same as what you experience.
M20 vs S1
Soundstage is wider on the S1 than the M20. The sound is also ever so slightly more open. However, with the S1, it does make the sound a little distant and less intimate. For some reason, I found the sub-bass to bleed into the mids more on the S1 and there is a now a veil over the midrange that isn’t present with the M20s which is rather peculiar. The veil is more obvious when I use the S1 module on one side and the M20 on the other.
M20, on the other hand, has more bass and a more intimate sound. Soundstage is not as open but the sound is less distant. Resolution is also better on the M20 due to the distant sound that the S1 brings to the U12.
I also found the S1 to sound a little weird with the U12s. On the S1, the bass is not as punchy or authoritative or visceral but there is still the strong sub-bass. Which I did find a little weird sounding as there is the sub-bass without the bass. There is also the matter of the veil over the midrange which I cannot put my finger on.
I found the M20 to sound better than the S1 as overall, not only is there a better bass response, the sound is also more intimate and does not have that weird veil over the midrange. The S1 just doesn’t sound “right” on the U12s.
M20 VS G1
The G1 again has a wider soundstage than the M20s. Bass response is also elevated when compared against the M20s. I did find the sub-bass to bleed a little more on the G1 as well. Bass is punchier and tighter on the M20s. There is also the distant sound that is characteristic of the ADEL modules.
Resolution is better on the M20s and has less bass and sub-bass presence than the G1. Notice I used the word “presence”. That is because the G1 brings the bass forward but does little else. With the G1, I found the bass rather overpowering and uncontrolled on the U12s. The irony is, I am not getting fatigue from the overpowering bass of the G1.
Personally, I am not a fan of the G1 on the U12s. The bass is just too overpowering and uncontrolled. The M20s provide a tighter and punchier bass response but also a more controlled one, and the sub-bass is not bleeding too much into the midrange.
M20 VS B1
Alas, the famed B1 and U12 combo. The B1 module opens up the soundstage of the U12s and in my experience, has a similar bass response to the M20s, although, I did found the sub-bass to have less presence and the bleed is now gone. As always, the distant sound characteristic is present.
There really isn’t much to say here. The B1 is basically an M20 with a more open soundstage and lower sub-bass presence. Resolution is better on the M20s but that is only very slight.
Personally, I prefer the B1 to the M20 as the sub-bass is now more controlled and is not bleeding into the midrange. The larger and more open soundstage is also a huge plus.
M15 VS S1
The M15s has a larger and more open soundstage than the S1. There is also less bass on the M15s than the S1. Bass is punchier and tighter on the M15. It is also more controlled and there is no bleed into the mids whereas the S1 as mentioned above, has that bleed. Resolution is better on the M15 as it does not have that distant sound that ADEL has.
With the M15s, the veil of the S1 is now even more apparent, and so is the sub-bass bleed.
Overall, not a fan of the S1 on the U12s. It just makes the U12s sound weird and veiled.
M15 vs G1
The M15 again has a wider and more open soundstage than the G1. There is also less bass on the M15s as compared to the G1 where it has that overpowering bass on the U12 as mentioned above. Resolution is better on the M15s as well with thanks to the tighter and more controlled bass response.
M15 vs B1
The M15 yet again has the wider and more open soundstage. It is airier than the B1 and has less bass as well. Bass on the B1 is more prominent and authoritative than the M15. As such, resolution is better on the M15.
Overall, I found myself to prefer the M15 over the B1 on the U12s as the U12s really do benefit from the less bass response and more open soundstage.
Apex vs ADEL Conclusion
Overall, I do prefer the M15 over all the other ADEL and apex modules for the U12s. The airiness and the open soundstage paired with the lowered and more controlled bass response do in my opinion, bring the U12s to the next level.
With that said, YMMV and you may prefer the other modules be it apex or ADEL. I hope this comparison will give you a better understanding of how the ADEL and apex modules compare to each other, even though it was made in reference to the U12’s sound signature.
Comparisons
All comparisons were done with the U12s on stock cable and M20 modules. The AK380 + Amp was used for all comparison.
64 Audio U10
The U10s were on the M20 module for this comparison.
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The soundstage on the U10s is slightly wider than that of the U12s. This is probably due to the differences in sound signature.
Bass
Bass on the U10s is definitely not as strong or authoritative as the U12s. Bass on the U12s are more thunderous and have much more presence. Bass rumble and texture are also better on the U12s. Bass on the U12s are also deeper and has better sub-bass extension.
Mids
Mids on the U12s are more sweet and smooth than that of the U10. It is also warmer and more intimate on the U12s.
Treble
Treble on the U12s sound distant in comparison to the treble on the U10. The treble on the U10 is more aggressive and “in your face” than that of the U12. Treble extension is also slightly better on the U10 than that of the U12.
Empire Ears Zeus XR
I swapped the cable on the Zeus XR to a stock plastics one cable in order to reduce the confounds and focus the comparison on the sonic differences of both the monitors alone.
Zeus-R
Soundstage
The soundstage on the Zeus-R is wider than that of the U12s. The Zeus-R has a more spacious and open soundstage while the U12s are more intimate.
Bass
Again, bass on the U12s is much more authoritative and stronger as compared to the Zeus-R. Although, bass on the Zeus-R is tighter. On the other hand, sub-bass extension and rumble is better developed and articulated on the U12s.
Mids
Mids on the U12s are fuller and lusher sounding. They are also warmer and more intimate. They are also smoother on the U12s.
Treble
Treble extension on the Zeus-R is airier than that of the U12s. It is also more aggressive and has more of a sparkle on the Zeus-R. Treble resolution is also better on the Zeus-R. The U12s have more of a laid back and softened treble as compared to the Zeus-R.
Zeus-XIV
Soundstage
The soundstage is wider and more open on the Zeus-XIV than the U12, but the difference in soundstage is not as much as the Zeus-R.
Bass
Bass is more visceral and authoritative on the U12s. It reaches deeper and has more texture and resolution than the bass on the Zeus-XIV. Although, the bass is tighter on the Zeus-XIV.
Mids
Mids on the U12s are warmer and sweeter sounding than the mids on the Zeus-XIV. They are more intimate and smooth on the U12s as well. I did find the mids to be more lush on the U12s but not by much.
Treble
The treble, like the Zeus-R, is faster and airier on the Zeus-XIV than the U12s. The treble on the Zeus-XIV is also more aggressive than the treble on the U12s.
Noble Audio Katana
Soundstage
The soundstage on the Katana is decisively larger and airier than that of the U12s. But then again, this might be attributed to the Katana and the U12s are going for different sound signatures, with the Katana going for accuracy and the U12s going for musicality.
Bass
The U12s has a bass that is more prominent and authoritative than the bass on the Katana. The Katana has a bass that is more controlled, tighter and punchier than the U12s. The U12s have more rumble and texture in the bass but the Katana has more resolution and micro-details.
Mids
The Mids on the U12s is warmer and sweeter than that of the mids on the Katana. Though, the mids on the Katana sounds more accurate and natural to my ears. I found the mids on the U12s to be smoother but not by much when compared to the Katana.
Treble
The Katana has better extension and air in the treble. Resolution is also better and the treble has more sparkle. Treble on the U12s are smoother and not as prominent.
Noble Audio Kaiser Encore
Soundstage
The soundstage on the Kaiser Encore is, like the Katana, wider and airier than that of the U12s. However, the difference is not as much as the Katana. Again, this could be attributed to the difference in sound signature.
Bass
Bass is stronger and more visceral on the U12s. Sub-bass has more presence and authority. There is also more texture and rumble in the bass. However, the Kaiser encore has a tighter and more controlled bass. It is also punchier on the Kaiser Encore.
Mids
Mids on the U12s are decisively smoother and warmer than the mids on the Kaiser Encore, but not by much. The Kaiser Encore still has mids that have a more natural tonality, versus the warmth on the U12s
Treble
Treble on the Kaiser Encore has more sparkle and resolution than the treble on the U12s. They are also more upfront and aggressive compared to the smoothened and slightly distant treble of the U12s.
Final thoughts
The U12s are a very special piece by 64 Audio and is worthy of its flagship status (although, its flagship status has been displaced by the U18 Tzar and tia Fourte). In a market where most flagships usually go for resolution and balance in their sound signature, I have to give credit to 64 Audio for daring to opt for a more musical, slightly darkened sound signature with the emphasis on the bass.
With that said, the U12s are not for everyone. Not everybody likes smoothness and musicality, and not everyone likes a sound signature with an emphasis on the bass, but those who do will feel right at home.
The U12s are a solid package with my only complaint being the provided tip selection, but really, that is very easily resolved. With the apex technology, the U12s prove themselves to be a very solid piece and one that I would easily recommend to anyone who is looking for a musical IEM.
@PinkyPowers: Thank you for the kind words! Hmm... I believe I may have poorly worded my M15 vs B1. While I found the bass to have more overall presence with the B1, the M15s did indeed have a punchier bass. I think it is just apex vs ADEL in general; apex modules gave the U12s the "bite" and punchiness of the bass that ADEL took away. I cross-compared this with my Athena ADEL as well.
Overall, I thought that the apex modules have a much better bass response than the ADEL modules in general.