The u12t is just a loaner from a friend.
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Oh well, I’m sure you’ll enjoy your time with it. Its said to be a really great iem. Enjoy.
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My review of the U12t IEM
64 Audio is a custom in-ear monitor boutique company located in nearby (to me) Vancouver, WA. They’ve built their brand around custom monitors for professionals, but also dabble in the audiophile market with various models throughout the years. This review will cover the $1999 U12t universal monitor, which is part of their audiophile line.
This IEM was sent to me on loan by Taron of Headphones.com and Headphones.ca. They are an authorized retailer of 64 Audio and you can find this IEM and other great headphone gear on their website! I’d like to also thank the Headphones Community forum and the Headphones Community Preview program for allowing loaner units sent out to community members!
Technologies
The U12t is a 12-balanced armature monitor that is part of their Tia line. It has 1 Tia high, 1 high-mid, 6 mids, and 4 low BA drivers per side. The tubeless Tia design also features the 64 Audio Apex and LID technologies. The Apex tech allows pressure relief through swappable modules that reduces air pressure during usage, with some slight changes in tuning depending on the module. The LID is 64’s linear impedance design, which allows the IEM to sound similarly regardless of the source impedance.
To test this LID technology out, I used my IEC-711-style coupler to measure the frequency response of the U12t with a near zero ohm output impedance source and then placed a 75 ohm impedance adapter between the source and the IEM cable and re-measured the FR. As expected, the measured response barely changed at all, so the LID technology works! I re-ran the same test with a couple other multi-BA IEMs in my staple (qdc Anole VX and Hidition Viento-R), and they all had significantly varying frequency response measurements at the two impedance values.
Accessories & Comfort
The U12t comes in a rather large box for how small the IEMs are. Within the packaging are the two sides of the IEM, a black 2-pin cable, various tips, 2 Apex Modules (M15 and M20), cleaning brush, clip, and a plastic carrying case with slots of each item. I wasn’t a big fan of the included cable, as it’s not the most ergonomic and easy to use, nor was I a fan of the case. It’s quite utilitarian in that it has slots for everything include the module and cable tie posts, but I found it to look and feel quite mediocre and rather unfashionable, especially compared to the cases that come with other IEMs which are fabric, leather, or jewelry-style boxes.
The IEM has a teardrop-like shape and rather simple contours; however, the fit is very comfortable in my smaller and sometimes finicky ears. I had no issues putting them on and wearing them for hours. I chose to use Spinfit CP100 (small) tips with this IEM as I found it was the best pairing for fit and seal, as well as sound.
Sound
The U12t has a U-shaped sound signature with heavily boosted sub-bass, a flat-tuned mid-range and a moderate pinna compensation in the upper-midrange and treble, and a rather soft and smooth treble range, at least to my ears and using the M15 gray module. Using the M20 silver module increases bass and reduces treble slightly.
Bass is actually presented very close to how I would like it to preferentially. Sub-bass is elevated while mid-bass is tamed down and closer in-line with the mid-range. Many people talk about how the U12t’s bass is good “for BAs” but I think the bass extends extremely well and has a natural decay level in most cases. It defines textures pretty well, though it does fall behind the best dynamic drivers in this category, but there’s no lack of slam, and sub-bass rumble here. In fact, I find it can be a little overbearing at times in songs where I don’t necessarily want so much low-end boom. I don’t necessarily think it’s bloated, but for certain types of music, I prefer a crispy definition, but the low end can over-power some other areas. This is specifically to some acoustic/classical genres, where a very deep and powerful bass or drum line can sometimes overshadow other instruments.
On most tracks, the mid-range is coherent and well-rounded. Since there’s no real dip in the mid-range, which is a preference of mine, I find that male and female vocals are played in-line with one another. Details in this area are showcased well, and instruments sound generally natural.
The upper frequency on the U12t is a little tame, and in this case, I find it lacks a bit of energy for some instruments. Female vocals don’t pop like they do on other IEMs with bigger pinna gain and treble boost, and some instruments like the crashes of cymbals and resonating plucks of strings don’t come off with as much zing and wow as I occasionally prefer. The treble brings the general tonality down to a very, very smooth presentation, that still retains clarity and high levels of resolution, which gives this IEM a very enjoyable experience for all music, and even let’s poor recordings shine a bit more than you’d see on other IEMs with more elevated treble responses.
Fatigue is never an issue with this IEM due to this, which is great, because the combination of the clean, comfort and the enjoyable, resolving listen, makes this a really great choice for those who just want to pop-in IEMs and not have to worry about anything.
I found the soundstage to be slightly above average for IEMs, with more depth than actual width compared to most IEMs. It’s not as wide as something like the Sony IER-Z1R and not as deep as the qdc Anole VX or Campfire Solaris, but there’s no worry of clogged up congestion or claustrophobia. Instrument separation is pretty good as well, which contributes to my previous statements.
Comparisons
In my short-time with the 64 Audio U12t, I’ve been asked how it compares to some of the other flagships. While I don’t have many of the ones I’ve heard in the past on hand, I have heard or owned many and can easily say that the U12t is among my favorites, and is a rather easy choice for a recommended all-arounder that can probably suit most users and most genres of music. That said, it doesn’t necessarily out-shine any IEM in any specific category.
It’s bass response, resolution, natural decay, and texturing and just general microdynamics, is really good, but it doesn’t top the Sony IER-Z1R as mentioned before.
In terms of general overall coherency, I don’t think the U12t outshines the Hidition Viento, as that one just sounds buttery smooth with out any sense of disjointed sound or significant timbre issues, though I do find some issues with it, I’ll talk about in its own review.
In pure resolution and detail resolution, the Shure KSE1200/1500 tops them all, and even for a multi-BA IEM, I still find the qdc Anole VX edging the U12t out with the Viento also in the same level.
And while fit is extremely comfortable, and this is a rather personal thing, I find the qdc shell design is outstanding for fit, size, weight and long-lasting comfort.
qdc Anole VX
When comparing this with the qdc Anole VX, I find they have some similarities as they’re both somewhat U-shaped IEMs. They both have rises in bass, a small dip in the mid-range and what I consider a good amount of pinna gain in the upper-midrange/lower treble and a small amount of treble extension. The U12t has more extended and bigger sub-bass performance, and you feel it with the lengthy rumbling decay, while the Anole VX isn’t exactly shy there either, but it is tamer, and more mid-bass focused with a little more more slam.
I found the VX to also have a little bit of warmer mid-range compared to the U12t, however I found the natural timbre of the U12t to be more correct in this area. The VX treble can be a tad hot at times, depending on the track, while the U12t is much smoother and toned down in the upper frequencies, and can reduce the energy and excitement factor in comparison.
Hidition Viento
With respect to the Viento Reference Universal, which is the switched model of the Korean reference in-ear, I found the U12t to have a bigger feeling bass region compared to the Viento-B tuning, which I believe is the closest matching to the U12t’s total sound. That said, they don’t really match a great deal. The VIento-B is more agile and coherent through the mids with a really nice signature that never feels totally disjointed ever. It is a tad shouty and can be sometimes sibilant, at least in the universal fit, but this is only a problem with bad recorded pop music. The Viento’s pinna boost is much larger than the U12t and also has a more elevated treble range, though also has similar extension capabilities.
Wrap-Up
The U12t is a really solid all-arounder and worthy of a lot of the praises I’ve read and heard about in the community and from other reviewers. While I don’t think it naturally beats out any specific IEM on the market in a specific topic, it performs near the top echelons of each category of the in-ears I’ve tried and that’s pretty good company to be in. I find it’s one of the easier IEMs to recommend for most all music types and can easily be a default option for anyone looking to start somewhere in the top tier bracket.
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Really great review. Some great comparisons too.
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Great review Ant…I’m going to be spending a few hours a/b’ing u12t with the rest of my current collection and I’m hoping to get around to sharing some impressions too (though I don’t think I’ll be ambitious enough for a full review lol).
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Looking forward to hearing those comparisons man 
! Especially compared to the Solaris SE !
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Hopefully you can share your impressions here too.
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For sure man…I’m trying to organize a 4-way shootout in my mind
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Great Reviews!
Got the U12t yesterday (secondhand) and listened to them and to the Andromedas.
I found that the Andromedas have a lot more treble energy and overall more forward sounding.
(Of course the bass is superiour on the U12t)
Is this also your impression?
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Just wanted to give everyone a heads up that @antdroid’s excellent review of the 64 Audio U12t is now featured on the headphones.com main page here:
https://www.headphones.com/blogs/news/64-audio-u12t-universal-iem-review-1
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I’ll A/B/C between the U12T/Andromeda OG/Andromeda Gold models
Andromeda Gold is my normal EDC IEM and has a bit more bass quantity…
Have you tried the more bass forward module for the U12T?
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so… I’ve been listening with a pair of Spinfits and a random Foamie tips I had in my collection. The spinfits add a lot of high-end brightness/sparkle and staging… I’ve been going back and forth between them and some foamies. Foamies add a lot of low end oomph…
I’ll switch to the bassy boy module here in a bit and swap and see how these tips compare with that module
But so far in general… these are excellent…mids are a bit withdrawn…but, even with that these are a very fun and easy listen… lots of detail, impressive staging… and in general not to recreate the wheel… I am pretty aligned with how @antdroid and @Resolve percieved them more or less. These are to me, at least a great TOTL level all arounder… with lots of options with different tips and the modules to really dial in what your preference is…or mood.
Comfort for me with all IEMs is always an issue, as my ears really dislike things in them for extended periods of time. They begin to ache usually within 30-60min of listening. But, thankfully, so far, the U12T has been able to surpass/equal my preferred comfort IEMs and I’ve been able to keep them in longer than average before the ache begins. I could see keeping these in for a couple of hours before having to take a break.
I’ll try and get some pictures today/tonight or this weekend 
Man, some acoustic guitar music just came on my random Qobuz playlist… these are killing it with the detail and sparkle!
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Thanks for your comment.
Yes I tried both, the M15 and M20, and M15 is more to my likings.
After another few hours of listening the „mental burn in“ started to work and i really enjoy them!
Still surprised about the big difference in the treble region between andro and u12t…U12t is warmer than i expected.
This post somewhere on reddit-forum explain my findings really good (quote):
Burn in/Mental burn in
Here’s what’s interesting about these two IEMs, they’re near polar opposites in tone and sound sig, while both being very satisfying. Switching back and forth between them emphasizes both what the former lacked, and what the current does well, which is a weird mental switch up. Switching to the A12t from the Andro, it feels a bit bloated, two dimensional and a touch V shaped. But after listening for 10-15 mins the A12t’s shortcomings in the upper mids fade away and I just bathe in that bass, wide soundstage, lush mids, and sparkly high detail of the TIA driver. The fit also makes it “disappear” at times too. Feels like an orb of rich sound is floating around me. Switching back to the Andro, it sounds tinny and narrow at first, but after a few songs that three dimensional holographic depth and incredibly cohesive tonality just makes me melt all over again…
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Ok, switched to the U12T Bass boys and it feels like the visual of a scale with too much weight on one side being shifted to the other side lol… bass is now the star of the show, while detail is still there just not as sparkly/airy. I see why you like the Sparkly grey module over the dark silver module…they should have corresponded the modules better…
Bass feels like when a bass guitar or stand up bass strums hard one string and the boom/decay lingers for an extended time…
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Ok, I’ve just been A/B/X’ng with my two pairs of Andromeda… the gold and the OG (original Green ) I think that was a bad idea… as I think the U12t has better refinement across the board plus isn’t as power sensitive. The Andromeda’s I think have better “holographics” but the U12t is right there with sparkle when it comes to the dark grey module… another thing I found interesting is that even with the more “Highs” emphasized module, bass is more present than either Andromeda. This now has me thinking about upgrading from my beloved Andromeda’s…but, I will say this… I do not like the 2pin system…feels to breakable and finicky… So I’ll keep looking, but I will say… the U12t is the ZMF Aeolus of the IEM world at least in my experience with IEMs. They just get a lot right with no major issues across the board. Plus with the modules and nozzle tips you can really dial in your preferred sound signature. Easy recommend! I’ll try and get my pictures edited and posted over the next couple days. =) Maybe consolidate my posts into a more concise “impression/review” post with the pictures.
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Aeolus is becoming the “best for everyone and everything” headphone!!! That say a lot about the U12t !!!
Due to some changes in my work these last 6-7 months (and it looks is going to be this way for a long time), the stationary set up is almost useless for my at this moment and for that reason I have been reading about “end game” IEM. Unfortunately this virus situation has put on hold our wallets, but reading and learning doesn’t hurt😉
The Tia Trio for about $1640 with the 30% off at this moment was very tempting, but I don’t want a divorce 
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This U12t , the Trio are candidates, now @Torq add a new to study about, the Unique Melody Mest.
Currently my LCD i3 is incredible, just need one like that one for moments when leaking sound is an issue.
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I used an iSine at work for a while and I didn’t have any complaints and it worked for my needs in a cubicle sprawl.
Where I work now, in tech world sea of desks, i dont know if it would be as easy to use.
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Most of the time I use open backs with my iFi Micro now that I have to move around and is almost impossible to stay by my Bifrost/SP200,
But some times I need lighter than the Micro BL and that’s when ES100 and Audeze i3 when a 2.5 balanced cable comes into action.
But…some times I need no leaking in and/or out and for that CCA C16 is my best one, but i3 spoiled me a lot, now I really know all I’m missing and it bothers me.
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I find the 64 Audio iem I have is great too. In my experience the U18t doesn’t have the immediate wow factor of the Andromeda’s. But 5 mins in then you begin to appreciate just what these iem’s are capable of. Enjoy.
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