Review: I Have Become Comfortably Numb – 64 Audio U12

Pros – Smooth sound, Great fit, Long listening without fatigue
Cons – Expensive, sound signature takes some getting used too


I love music and I love good quality sound and this is my hobby. I prefer to find the best portable setups available as I do not like to be stationary. I do not want to be tethered to a desk with an amp, and for that reason I have never bought a desktop rig. If I want to walk away, and make a drink, I want to pick up and go while still listening to music. In other words, enjoy excellent sound whether I am walking the dog, going to the gym or hanging out at the pc. I don’t rely on graphs or charts, when I listen to music my ears tell me what I like, not my eyes.

64 Audio U12/Adel-S1/B1 Module
-MRSP (Universal): $1599 w/S1 module

They say idle hands are the devil’s workshop, and I must say that phrase has my name written all over it! I actually was at a point where I was quite satisfied with my stash of gear at the time and my go to IEM was the Rhapsodio Solar. I reached a conscious decision to finally settle in and sell of some gear and fade into head gear and HeadFi obscurity. I have reached end game NIRVANA no more buyer’s remorse no more splurging, no more floating credit [​IMG].  I have no will power and had to take the first step in curing my problem and I admitted I had a problem so I bought another iem and succumbed to my demon. That demon iem is the 64 Audio U12.[​IMG]

I must thank a fellow HeadFi’er who was willing to feed my habit and I purchased an excellent condition, low hours U12, with the S1 module. Thanks Jozzur!

Honestly, I am not sure why this IEM was on my radar, but it was. There are many options in the $1000.00 – $1500.00 used range. I mean folks love the 64 Audio U6, the Andromeda, Empire Ears and so on. I already had the Solar with 10 drivers and I loved them…addiction is a bitch!  What really drew me to the U12 was the fact that I am sure my hobby has contributed to the fact that I have tinnitus and here’s hoping that the Adel modules will help with that and more drivers has to be better…right?


After we made the deal I began to do more research, which I know is the reverse of what normal thinking people do. The purchase came with everything stock including the S1 module and in my research the S1 was not the module of choice, the S1 appears to create a veil and a bassy signature. I searched the sale threads for a B1 which appeared to be the module of choice for the U12. But alas no one had one for sale. 64 Audio has also made the choice to switch from Adel to Apex so I was becoming more confused and frustrated, and then you throw the MAM module into the mix and this was becoming more than just a plug and play decision.

THANKS TO [​IMG] This is the company that created the ADEL modules. Rather than waste more effort I ordered the B1 module retail direct from these guys which many think is the preferred module for the U12 creating a more balanced, airy and open sound. The order was immediately shipped and I actually had it before my U12’s arrived. Thanks for the quick service!
I would still like to hear the MAM module and if I have the opportunity I will edit the review to include that module.

When the U12 arrived I was excited to take in all of the glory that was the U12. WOW, a rather small, unimpressive package, with a sinking feeling I opened the 64 Audio box to ONLY be equally underwhelmed at the hard case that I was looking at! I opened the hard case and I saw a plain black acrylic shell with a thin black cable. The first thought that came in my head was there is always the For Sale thread and to chalk it up as another life experience, shame on me why did I spend so damn much. I was expecting that face melting Indiana Jones, Holy Grail experience.

There are plenty of unboxing videos and photos of the 64 Audio products so you won’t find that in this review, accessories are the basics to get you by and the packaging is minimal, enough said.

On to the show:

Comfort is really good. Considering there are 12 drivers it is pretty amazing how comfortable these are. There were two things that made me sell the Layla, ergonomics and seal. The Layla were like Frankenstein bolts and fortunately the U12 are not. They are well designed, comfortable and I can use them for hours without discomfort.

The stock cable is thin, light, and flexible and feels very average overall. The review I am writing is not using that cable, I have a couple of Rhapsodio cables and after a brief listening session with the stock cable I switched to a Silver Litz 4 braid cable. I also have the SPC Pandora by Rhapsodio but I have not tried it as the Silver Litz is more comfortable than the stiff copper one. I am not a big believer in a cable changing a sound signature as opposed to impedance changing the sound. However, I do like more comfortable cables so I used the Silver Litz option I had.


I have tried many eartips in my time with this hobby, but when fit permits, I always seem to prefer the JVC Spiral Dot tips and it’s large bore and with the U12 it is no exception. I will say I am fortunate to use large tips with this IEM because they have a very long nozzle and any size but large will leave nozzle exposed, and lord only knows we can’t have our nozzles exposed. I am using the Spiral Dots for this review.

I have used two sources during this review and they are my Google Pixel Xl and a Cayin i5. The Pixel is pretty standard listening but really not bad and the Cayin i5 which has been characterized as a warm, but clear sounding dap. The review is not about the dap but I will say the sound signature of the i5 has changed with time for the better and this dap is powerful enough to drive the HD650 so the more time I spend the more impressed with the sound I become. The detail and openness of the i5 are starting to become more apparent.

When I started to write this review I poured a Barbancourt 8 year and Diet Coke and put the U12 in my ears with some Metallica as motivation. At this point I am on my second beverage and have passed Metallica and Praxis(Transmutation Mutatis Mutandis) and am on to some Red Hot Chili Peppers,The Getaway.

Upon first listen with the stock cable and the S1 module I could not believe what I was hearing. This was the most polarizing, confusing sound I have ever heard in an IEM. The frequencies seemed jumbled and the high end was weirdly mixed into the sound and they were a warm, thick sound. I went back to my comfort zone and put the Solar in my ears…ahhh relief. I prefer a musical, slightly warm sound for my headphones and IEM’s but this was an entirely new level of warmth. I never crave treble and loathe anything that can be strident or harsh but I found myself wishing for treble.

The 64 Audio U12 contains a dozen Balanced Armature Drivers in each ear, four bass, four mids, and four highs. With the ADEL S1 Module, the U12 is surprising how warm an IEM can be. A switch to the B1 module and there is air and a wide soundstage. The details shine through with a tonality and smoothness that creates a relaxing smooth listening experience. Thank God for the B1 module. I would be curious now that I am accustomed to the sound if the S1 is still off sounding to me maybe one day I will try them again.

The Silver Litz cable and B1 module have been the setup I have stuck with. For the review I am using the Cayin i5 with the U12, Spiral Dots and Silver Litz cable.

I gave the U12 a lot of time before writing this review and now I must say I am a believer…..what a great sound!


The bass on U12 is deep in the sub level and detailed with layers in the mid bass range. The overall sound signature is warm but the tone of the bass and layering of the bass range is awesome, one of the best I have heard… bar none. As a comparison the Angie’s level of bass could be increased but can’t reach the detail levels of the U12. The Solar has excellent bass detail but is still bested by the U12. The Heir 8.0 has a bass presence throughout the signature, however the quality is not on par. There are layers and textures in the U12 that extend deeper than many over ear headphones I have heard. Color me warmly impressed!


The mids are clear and incredibly detailed but you will not realize this when you first listen to the U12, they appear to have a bit of a veil. With brain burn-in you realize there is not a veil at all it is how the frequencies are served up. The tone of all vocals shine and with male vocal sounding strong and females sounding sexy. The soundstage is good and the imaging was providing me with some occasional nice effect. The U12, have a warm, smooth, sound while creating space with the B1 module. In comparison the Solar are a bit cleaner and a bit more detailed sound out of the box. The U12 requires some getting used to in order to appreciate just what all is going on. If you dedicate the time you WILL be rewarded handsomely!


Treble is delivered differently than any other IEM I have heard. It is certainly not the focus. It is restrained and included as part of the rest of the mix. It extends and is not lacking and not rolled off. It is just blended into the mix which creates an illusion that the treble is neutered. This one aspect has taken me the longest to grow accustomed to. It is a bit of a strange sound signature that had to grow on me longer than any IEM I have heard. They are so smooth, warm and never fatiguing. Never any sibilance or harshness. I can listen not fatigued for hours. In comparison I feel the Solar offers a more balanced sound and is clearly more sparkly than the U12. If you need a more sparkly treble I would say the Solar would be more to your liking.


I have spent quite a few hours of listening to the U12 in a short time already. After the initial listen and growing accustomed to them the U12 has really become an incredible sounding IEM. They are a very musical with a great tonality. The sub bass rumbles as well as is clear and defined in the other ranges. The mids offer a great deal of clarity and are very detailed while the treble is skillfully blended in the mix.

I have listened to many genres of music with them, from Jazz, Blues, Classic Rock, Alternative. Streaming on the Pixel or listening to HQ quality on the Cayin i5 the quality is excellent.

Overall a warm(good warm), detailed presentation. It delivers an experience that you can listen to for hours without fatigue.

On a final note…You will be rewarded if you have the patience and allow your brain to adapt to the presentation. These are incredible sounding and have become my go to IEM. Will this IEM cure my addiction to this hobby and allow me to say end game achieved, maybe, but what would I do with my time or money?

Buy Them!!!!

EDIT:  Since the review I have purchased an OPUS #2 and the fact that the DAP is more neutral and has a balanced output has taken these IEM’s to a sublime level. The majority of the congestion is gone and more details are shining through. These really shine with a DAP with a more neutral signature.