1964 Ears ADEL A12 Custom IEM


Headphoneus Supremus
Pros: Highly Detailed/Textured Bass, Massive stage, Thick Syrupy Mids, Rich Vocals
Cons: Recessed Treble
          Review Introduction
          Product Introduction
Technical Specifications
Sound Analysis
          Layering And Separation
          High Frequencies
          Middle Frequencies/Vocals
          Low Frequencies
Suggestions For Improvement


Review Introduction
          I am both a stereophile and an audiophile.  I am an audiophile so as to further my enjoyment of the music I consider essential in life.  Life without music isn’t much life at all, when I’m able to hear more detail or the song better rendered the reason for audiophile gear becomes is clear.
          I have been listening to the ADEL A12’s for approximately 2 years.  I got my A12's right after the Kickstarter campaign while they were still being shipped with the prototype clear plastic ADEL modules that were a precursor to the metallic S1 modules.  I reviewed the A12 around that time but now I have decided to redo the review now that I have heard the A12 with these new apex modules as it is quite a different IEM now.  Both the apex A12 that is being sold now and the ADEL A12 have the same tuning as confirmed by 64 Audio so this review will be a comparison between ADEL and apex with regard to the A12.  For this review I will be using the apex M15 and contrasting that with the ADEL MAM, I believe these two modules are the best that each company has to offer at this time with regard to modules.  It seems hard to fathom that such a small module could change sound to such a degree but it does.  I own and have used all the currently available modules with A12: G1, B1, S1, MAM, M15 and M20.  Each section of the review will feature discussion of ADEL and an apex.  This should help differentiate the two different technologies and their effects on pressure and signature.
Product Introduction
          The A12 is an IEM from 64 Audio it used to be their flagship until the A18 and Tia Forte were created.  The A18 and Tia Forte exceed A12 in price but A12 holds its own in some ways.  The A12 now ships with apex module that vents pressure and allows the user to alter sound signature by changing modules.  As of April 2017 there are two apex modules available: M20 and M15.  M20 provides 20dB of isolation and more bass presence while M15 provides 15dB of isolation and a more balanced signature.  M20 has a single vent hole while M15 has dual vent holes.
          The shells are 3d printed and you can customizable your own on http://www.64audio.com.  Due to the 3D printing process my fit is perfect.

Technical Specifications

          The A12 has 12 drivers: 4 high, 4 mid and 4 low drivers that merge into a three way passive crossover network.  From there the sound is channeled through the sound tubes and into your ear via three sound bores, a fourth and the largest bore sits at the bottom of the canal.  This fourth bore designed to vent pressure inside the canal and channel it to an ADEL or apex module.  A12 operates at a 12Ω @ 1kHz. output impedance.  1.png
The A12 is shown on http://www.64audio.com as having an elevated sub and mid bass.

Sound Analysis

          When discussing stage I differentiate between headstage and soundstage.  Head stage is the distance we actually hear the sound coming from as we consciously focus on that distance.  Think of headstage as listening while holding your hand over the IEM/headphone (you are aware the sound is coming from inside it) and thus the size of the stage is diminished because of this awareness.
          I experience a soundstage when I disappear into the music without thinking.  It’s best done in a dark room with eyes closed.  What the brain is consciously aware of about the visual, thinking and tactile processes affects how we perceive the soundstage and headstage.
          Imagine a human head with a 3D axis placed in the center of it.  The Y-axis is the height, the X-axis is the width and the Z axis is the depth.  From these three planes we can form a 3D representation of both headstage and soundstage.
          The shape of the stage doesn't change with modules therefore stage can be discussed without needing to include modules.  The shape is roughly a horseshoe.  If you've been in drawing class then you'll be familiar with the lesson on left to right perspective:
      A12 is a lot like this perspective image to the left with regard to stage.  It has a very wide stage, much wider in the X-axis than it is tall in the Y-axis.  The A12 does very well conveying a sense of distance in the X plane due to it's massive bass drivers which darken and warm the sound making high frequency notes sound further away via contrasting.  The effect is not as apparent on vocals as it is on drums because vocals are positioned closer to the X and Y intersection and are thus more textured. 
ADEL Stage:
          The ADEL A12 sounds slightly more expansive in all directions than the apex A12 with the biggest difference being in the X-axis where the ADEL modules creates approximately an inch of extra headstage width.  The effect of everything sounding slightly further away in all planes is due to the "resonant fog" that the ADEL creates.  "Resonant fog" is the best way that I know how to explain it.  It's an airiness that ADEL casts over the sound combined with what sounds like a resonance that happens very fast; in fractions of a millisecond.  If you're a stage fanatic you'll enjoy that extra spaciousness of ADEL but at the expense of resolution.
apex Stage:
          The apex head stage is slightly thinner than the ADEL head stage with regard to width making it about 2" outside the ear on the X-axis.  It's easier to pin point sounds in the apex stage because of the lack of resonance and higher detail.  I prefer the apex M15 stage due the clarity, better separation, higher detail and pin point accuracy within the stage.     
                  The A12 has an exceptional soundstage irrespective of apex or ADEL.  To my ears it’s massive in all directions.  Soundstage width is massive and the most noticeable aspect of the stage.  Listening to songs with wide soundstages produces the effect of sounds coming from several inches outside the CIEM.  When I turn the lights off, put in the A12's with the ADEL MAM (knob all the way in) I experience a true 3d soundstage.  In spoken passages I often felt like there was someone behind me in the room and the feeling was scary at times.  The tonal realness and natural pressure free environment that the ADEL modules create goes a long way toward creating this holographic effect because ADEL allows your ear to hear the way it naturally does as if the you didn't have IEMs in.  I experience less of this hair tingling effect with apex but apex is more detailed and creates a distance effect by increasing texture detail.  This increase of detail of the apex modules creates more contrast between high resolution textures and low resolution textures, the human brain interprets highly textured sounds as being closer therefore this contrast between textures creates a distance effect in the apex sound.    Soundstage shape remains the same regardless of module.
          The background of the A12 is utter blackness and voidness.  When paired with a warm source like the Chord Mojo with its’ inky black stage the effect is quite pronounced.  The A12 isn’t a detail monster-except in the lowest registers.  It’s extremely warm.  The sub and mid bass extend far into the mids and highs muffling the upper mids and highs.  This effect is more pronounced in the ADEL modules than the apex modules.  I hear more isolation and higher resolution with the apex modules.  The apex module contains a resonant absorbing material to eliminate resonance created by having a module and canal in an IEM and the apex passageway is engineered to have little to no resonance as well via 3D printing.  This lack of resonance increases the resolution of the monitor when used with an apex module. 
          Tonally speaking the A12 is very transparent sound when paired with high quality sources.  Regardless of whether the note is a high note or the deepest sub bass frequency the A12 renders the notes in a transparent manner with natural timber and tone.  Bass especially has a lot of impact much like it would if you were at a live show.  A12 recreates that full bodied hit, rumble and punch in a tactile sense more than any IEM I have heard to date.  Bass heads rejoice this will likely be your favorite IEM.  The highs carry a similar sense of naturalness in tone and transparency although their decay is quite a bit less than the low end.  With regard to modules transparency is roughly equal except for the low end in which the ADEL modules provide a more visceral tactile feeling to the lower mids and lows.
Layering and Separation
            Due to the aforementioned mid and sub bass bumps, the A12 isn’t exceptional at separating layers and isolating instruments in stage.  It does an admirable job but the sound is too congested for separation to be spectacular.  The M15 apex module goes a long way toward improving the layering and separation.  The ADEL MAM offers the best layering/separation from the ADEL side but isn’t nearly as good at it as the apex M15.  M15 increases the ability to perceive the origin of a note, making its emergence a pinpoint experience whereas the less detailed ADEL sound is better at creating a distance effect than a layering/separation one.   Pairing the A12 with a DAC that has exceptional layering/separation like the Chord Mojo or Hugo2 is a great way to squeeze out every bit of layering/separation the A12 is capable of.
High Frequencies
            The weakest point of the A12’s sound presentation is the high end.  Sparkle is absent from the A12 and the powerful sub bass makes high notes sound far away in the stage.  Upper mids and highs have little weight.  Female vocals sound distant whereas male vocals sound close and intimate.  Highs sound as if they’re pushed to the edge of the stage.  If you don’t mind this recessed high end and prefer a larger stage this could be a good thing.  There are a few things you can do to increase the high end.  The most improvement comes from the apex M15.  It increases detail in the upper mids and highs while restraining the low end and increasing texture across all frequencies.  If you prefer ADEL you will need to use the B1 or MAM to restrain the low end.  The Ultimate Ears Buffer Jack has the biggest effect toward creating a more balanced signature on A12 but it also compresses the sound and neuters dynamism.  Pairing A12 with an exceptional amp like the ALO CDM results in more extension in the high end.  The A12’s seem to need to be a powerful amp to be dynamic and present more high end.  Pairing A12 with high output impedance sources or sources with bright signatures will also tame the bass and allow the highs to be revealed.   
Middle Frequencies
          The A12 sacrifices mid-range detail for musicality, impact and a more full-bodied sound.  Mids are very full sounding due to warmth being favored over detail.  With ADEL modules like G1 or MAM you can get mid-bass to punch very hard to the point that bass guitar vibrates the canal on especially heavily amped and down tuned guitars.  Male vocals are very emotive and impacting while female vocals are distant and much less  emotive.  The A12 is one of the few monitors that I’ve heard that have a syrupy mid-range.  Mid-range notes can sound incredibly dense and fat in the lower middle range.  This warm mid-range combined with an emphasized sub bass makes the A12 sound slow and sluggish with fast music but simultaneously epic, towering and massive with slower music.          
Lower Frequencies
          The sub bass on A12 is powerful, detailed, textured, decays for ages and emerges authoritatively from a deep inky black stage.  Regardless of what ADEL or apex module you use, you will get top of the line balanced armature sub bass from A12.  It hits like a sledgehammer.  Sub bass impacts the stage from far away and displays excellent decay as it fades away without losing detail.  It can emerge from all directions; behind, front, back, left and right.  It has a real 3D effect to it.  The ADEL modules will give you a more vibratory and tactile sub bass while the apex M15 will give you a more textured but still quite slamming sub bass.  The sub bass is the best I’ve ever heard in a balanced armature based IEM.


          The A12 is a picky CIEM.  It likes high output impedance sources or low output sources with a bright analytical signature-assuming you want more high end out of it.  Low impedance sources will typically increase the veil over the upper mids and highs while high output sources and bright analytical sources will typically produce a more balanced sound with more high end.  Regardless of source the sub bass and to a lesser extend the mid bass will always be dominant over the upper mids and highs.
Chord Mojo:
          There was too much of a roll off in the high end for me to enjoy the Mojo and A12 pairing.  The B1 and to a greater extent the M15 reduce the low end allow the highs more stage presence but it still is not enough for me to enjoy this pairing.  The veil is too great, too much detail is lost and the signature is too dark.  The incredible amount of detail that Mojo produces is lost in the blackness.
          The ALO CDM in DAC and amp mode is an interesting pairing for A12 because the CDM is a warm device yet it gives the A12 more high end.  All frequencies tighten up with regard to decay and deepen with regard to extension.  The very highest and very lowest frequencies are both increased.  The already massive stage of the A12 is made even more spacious especially with regard to space between the instruments.  The increased space creates a more precise sound.  Everything is thicker, more dynamic, spacious and lush than with Mojo.
Chord Mojo + ALO CDM:
          This is my favorite pairing with A12 and the cherry on top is the M15 module.  With this pairing you get the incredible detail and resolution of Mojo combined with the lushness, thickness, spaciousness sand dynamism of the CDM.  The CDM is being run in amp only mode in this case.  The biggest difference versus using only the CDM is the amount of texture detail that the Mojo is able to create.  Decay from both the low and high end is far more detailed than with CDM alone. 
S7 Edge:
          The sound quality takes a pretty significant negative hit when pairing the A12 with the S7 Edge.  The bass becomes even more bloated while detail decreases as compared to the other sources.  Stage also diminishes in all directions. 


          The A18 trounces the A12 in resolution due to its’ tight bass and detailed upper mids/highs which exhibit excellent decay and extension.  A18 renders more detail and nuance, the A12 is more fun sounding with a harder hitting low end and thicker syrupy mids/vocals.  The A18’s are less congested than the A12’s.  The start and stop of each note is also more pinpointed on the A18’s.  A12 has more detailed/textured sub and mid bass.  A18’s highs and upper mids decay longer while A12’s sub bass has more decay.  A12 has more bass quantity across the board which makes the stage sound wider as it contrasts the highs vs the lows.  The highly textured upper mids/highs of the A18 make the stage sound slightly smaller than A12 because sounds with a great deal of texture sound close to us.  The bass heavy signature on the A12 makes it sound sluggish and less resolute with faster music while A18 is a speed demon.  A18 is more sensitive and exhibits a slight hiss, the A12 exhibits no hiss.  Due to the A18’s hiss the A12 has a blacker background.  A18 has better layering, separation and space between sounds.  A12 has a more airy sound overall.   
          The A12 pairs poorly with most sources.  The A18 sounds great out of everything from my iPhone 5 to my CDM.  The A18’s single bore makes cleaning a breeze while the A12’s multi bore makes it a pain.  The A18’s are larger in all dimensions than A12, only the faceplates are the same size.
CustomArt 8.2:
          The A12 is a lot warmer than the 8.2 but 8.2 isn’t bright either because it has an elevated sub and mid bass as well.  A12 has less detail in all areas except the sub and mid bass in which it has a more detailed and textured sub bass.  A12’s sub bass goes much deeper than the 8.2’s sub bass and it slams and punches much harder.  The A12 stage is larger in all directions.  The mids are meatier on the A12 while the 8.2 prefers to keep the sound light and airy across all frequencies.  The thicker mids on the A12 render male vocals with a lot of emotion and impact while the 8.2 has a less dramatic vocal presentation.  The 8.2 has more detail in the upper mids and highs.  The 8.2 has much more extension in the upper mids and highs whereas the A12 is recessed in those areas.  

Suggestions For Improvement

          The smaller sound tube bore holes on my A12's have excess material around the rim, this excess material becomes a trench for the collection of wax making it extremely difficult to clean the small bore holes.  I also had the stock cable break where the cable enters the CIEM.  Several other users reported the same problem.  Seeing this, 64 Audio went back to the drawing board and redesigned the plastic around the end of their 2 pin cables.  They created a stronger fiberglass resin connector and I am happy to report the issue is solved.  The new cable is much stronger than the previous iteration and they went the extra mile and sent me one of the new ones for free to replace my broken one.  I also had an internal crack appear in a critical area (in the center near many of the sound tubes) inside the left CIEM after about a week of using them  I sent it back for repair and 64 Audio repaired it free of charge.  I have now acquired their latest flagship the A18 which has 18 drivers and I am happy to report that 64 Audio has evolved beyond even having sound tubes that far down in the canal.  They now use a massive single bore which makes cleaning a breeze.  I used to clean my A12's everyday but with this new mesh covered single bore design I can just wipe down the outside of the canal area and give a quick swipe to the inside and my IEMs are clean.  Please have a look at my A18 review to see for yourself: http://www.head-fi.org/products/64-audio-1964-ears-a18-tzar/reviews/18444


            If you’re someone who prefers a smooth signature with deep, powerful, textured and hard hitting mid/sub bass you’ll love A12.  A12 has an exceptional sound stage that will please even the most diehard soundstage fanatics.  If you prefer a highly detailed upper mid range with a lot of micro details in it or a sparkly treble you may want to look at A18.  Thanks to the modules you can alter the signature to your liking.  I highly recommend looking into a powerful amp like the ALO CDM for the A12's as well the M15 module.
I don't think all 64 audio CIEM's are poorly built, I did have bad luck with mine though.
Not saying they are all bad either, but if they cant  QC their TOTL piece.... I would rather drop 2 grand elsewhere (my own personal choice based on your experience)
Great review, I hear the sound exactly like you described and it's why I ended up selling my U12s.


twister6 Reviews
Headphoneus Supremus
Pros: driver coherency, resolution, spatial details, ADEL module.
Cons: additional cost of MAM tunable module, not for those craving revealing/analytical sound.

I would like to Thank 64 Audio (former 1964 Ears) and Asius Technologies for providing me with review samples of A12/U12 and ADEL MAM module in exchange for my honest opinion.
64 Audio website: http://www.64audio.com/ with a direct link to A12: https://www.64audio.com/product/1964-A12-Custom-In-Ear-Monitor and U12: https://www.64audio.com/product/1964-U12-Earphone
Asius Technologies website: https://asiustechnologies.com/tech
* click pictures to expand to full size

Over the last few years and many headphones I tested and reviewed, my focus was always on the sound, the driver config, the design, and the accessories.  There wasn’t anything else revolutionary to talk about, and it seems like every new design was just a different cooking recipe from a pool of the same ingredients.  Though I never had a chance to review the original 1964 Ears monitors, I have read a lot of positive feedback and saw them as an established name in custom and universal IEM market with a typical clientele of performing artists and audiophiles.  So why would they take a risk and partner up with one of the pioneers of in-ear monitor technology to re-invent the wheel?  It’s obvious that Vitaliy and his 1964 Ears family, including a number of his actual siblings, really believes in Stephen Ambrose and his Real Loud Technology (in a form of ADEL module) which became a staple of every custom and universal model introduced under a newly rebranded 64 Audio company name.
The convenience of digital audio format, portable audio players, and smartphones all together propelled the popularity of portable headphones.  While some still prefer the experience of listening to speakers when in a car or in a living room, the improvements in headphones sound quality made a lot of us realize that you can make speaker experience more personal, scaling it down to IEM level.  But that is also a double edge sword where you could be enjoying the music while damaging your hearing without even being aware of it.  As someone who used to listen to plenty of bass heavy music, I never questioned and actually welcomed the visceral low end rumble which only got intensified when I switched to the largest eartips for a better seal.  I didn’t know that in addition to a typical sound pressure, I was also experiencing a harmful effect of pneumatic pressure produced by the drivers. 
Apparently, this pressure triggers an acoustic reflex, a mechanism that protects our ears from a loud sound.  Constant exposure to this pressure causes unnecessary triggering of this reflex which can wear it out and cause a permanent hearing damage.  Stephen’s Real Loud technology adds a release mechanism that allows this harmful pressure to escape, and this technology was encapsulated inside of ADEL module which stands for Ambrose Diaphonic Ear Lens.  More info about this could be found here: https://asiustechnologies.com/tech.
In reality a lot of us don’t want to be lectured with medical details or to be bothered reading about steps necessary to avoid hearing loss.  So have no worries, I’m done with my preaching!  After all, the main focus of this review is flagship TOTL 12xBA driver monitors, and I’m well aware that people are more interested about the sound and the effect of the ADEL technology relative to this sound.  But keep in mind, Vitaliy and his 64 Audio family teamed up with Stephen Ambrose to deliver not only the premium sound quality but also the design with ear health benefits.  Now, without a further ado, let’s proceed to the review.
Choosing the design.
I already mentioned this in a lot of my previous reviews, going with a custom fitment is a commitment on many levels.  You are guaranteed the best fitment made from in-ear impression taken by your local audiologist, you can customize the design to your liking with anything from shell color and finish to faceplate material, you eliminate the extra bulk of multi-driver universal shell sticking out of your ears, and also CIEMs guarantee to fit only you which deters others from “borrowing” it.  But at the same time, custom fitment requires longer waiting, you can run into issues requiring re-fitment, you can’t easily sell to upgrade to another model if you are not happy with a sound, and the shape of your ear canal can change over time.
I started my review with A12 based on impression that was on-file from awhile back and ended up with a re-fitment due to a weird shape of my left ear canal.  I actually feel that my ear canal fluctuates with weather changes and occasional sinuses where I’m at a mercy of a fitment which prevented me to start my proper review until I switched to universal U12.  With Universal you have to realize that fitment will heavily depend on a correct eartip selection which controls the seal and will affect the sound, especially the low end impact.  My choice of U12 over A12 was driven by my ear anatomy, but either selection will yield an identical driver configuration and sound tuning.  Overall, it’s a great business model where 64 Audio offers both Custom and Universal fitments in all of their 2-/3-/4-/5-/6-/8-/10-/12-driver designs.
With universal fitment you get an instant gratification of a pre-build model that will ship to you door within a week, but you also forfeit customization option, and it will be a generic compact black shell with a printed “64 Audio” on the left faceplate and “ADEL” on the right faceplate.  With custom A-model, the fun starts when you enter on-line DESIGNER tool.  You start with a model selection, where btw in addition to A2-A12 you can still find legacy 1964 Ears Q and V models.  In the middle of the screen you see a generic image of the shells where you can switch between Left/Right sides and see the cosmetic changes in real time.  The model selection screen also offers you a choice of a standard 48” cord or extended 64” variant, and a selection of either normal or a more secure recessed socket.  The socket itself is a standard universal 2-pin connector which you can use with any aftermarket cable, but be aware that some cables have connector housing that doesn’t fit recessed sockets.
On to a color selection, starting with a shell you only have 3 choices of either black, all clear transparent, or charcoal translucent.  Not as many choices in comparison to some other manufacturers, but you can compensate for lack of shell colors with a wide selection of faceplate colors, finishes, and premium material.  You get a few dozen colors in standard or glitter finish, or can go with 6 different premium material faceplates, or 6 wood finish faceplates.  Obviously, faceplate itself will not be exposed to outside and usually laminated by acrylic layer of the shell.  In addition to color selection, here 64 Audio also offers you a choice of cable color to match the shell.
Artwork tab will allow you customization of the logo where you can select from pre-defined ones in any of 7 colors, or to upload a custom artwork which has to be checked by 64 Audio to determine feasibility.  Before you proceed to the check out, you have an option to add your name on the case, specify name of the person wearing it, notify if this is a rush order, and also to mention if you are sending new impressions or allowing 64 Audio to use the one stored on file.
Once order is placed and you receive confirmation, 64 Audio offers something which I haven’t seen with any other manufacturer – a progress bar report which you can login to anytime to check the progress of CIEM manufacturing.  It will date each step of the manufacturing process and will provide you with a brief description of what they are working on.  It could feel dreadful when you have to sit and wait 4-6wks for your customs without knowing what’s going on.  Here, it makes the time go faster and you know exactly what they are working on.  Maybe 64 Audio doesn’t offer as many exotic colors or finishes, but they make up for it with a progress report tracking and excellent customer support.
Unboxing and Accessories.
The unboxing experience should be common for either custom or universal models.  Majority can probably relate to this where with CIEMs the number one priority is to check the fitment out of the box, but I had to take a pause after I removed the outside sleeve.  First of all, the packaging box itself is very compact – a dead giveaway that you are dealing with a custom case and not your typical Pelican box.  After you lift another cover you will find a printed Quick Start guide talking about putting earpieces in and paying a close attention to volume adjustment – a strong indicator that 64 Audio is very serious about a hearing health.  Inside of the box you will find a plastic rectangular storage case and a partitioning section with dehumidifier “tablet” commonly used with CIEMs to dry out the moisture accumulated in the nozzle.
With dimensions of about 120mm x 70mm x 35mm, the case is smaller than a typical CIEM Pelican box, but its “beauty” is on the inside, not the outside where I found 64 Audio logo and my “Twister6” faintly visible name.  This is a truly custom case with a level of partitioning like I have never seen before.  You have two separate deep sections for each earpiece with a rubber lining and a slit for a cable.  Then, you have a split core cable winder where you start off by pulling the cable from each earpiece through a split and then winding it around the outside.  When done, there are 4 vertical holes to park your headphone jack, whichever closer for the reach.  Obviously, this is more appropriate for a right angle headphone jack, but I had no issues with a straight connector and my heavy aftermarket cable – there was plenty of room for everything.
Between the earpiece pockets and the cable winder, you have a small round area to hold securely the “dehumidifier” piece.  The cover of the case has a soft lining right above the earpiece area so when you close it – earpieces won’t touch the plastic top.  Also in the middle you have a secure holder for a cleaning tool with a brush on one end and earwax remover on the other end, and another place to attach a shirt clip.  Both of these removable pieces fit secure and nothing will rattle or move loose as you carry this case.  There were also 4 pockets for 2 pairs of ADEL modules to keep your spare adjustable or auto-modules securely stored.  Also, underneath the latch you will find an air vent to release the pressure as you close the lid, sealing the vent when you engage the latch to close the case - keeping everything airtight and secure.
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Case and accessories.
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The included silver-color stock cable, arrived with A12 (U12 comes with a black cable), is one of the best looking 2-pin generic cables I have seen among the other reviewed IEMs/CIEMs, but at the same time I felt it doesn't do A12/U12 justice.  As always, I strongly encourage people to wait with a cable upgrade until you spend more time getting to know the sound of your IEM/CIEM with a stock cable first.  Otherwise you will not be able to hear and to appreciate the benefit of the upgrade.
The stock cable definitely looks premium with a translucent right angled connector housing and a nice strain relief where you get a clear view of soldered wires on the inside.  The cable has 4 braided conductors, 2 from each earpiece, where the L/R grounds are not joined until the headphone jack.  Y-splitter is a typical piece of a short shrink tube and chin slider is another clear piece that slides up/down.  The twisted pairs of the cable going to the shell connector have a memory wire, and connector itself has a standard universal 2pin jack and Red/Blue id dots to distinguish right/left sides.  Universal U12 comes with a standard black cable, but I'm sure you can request from 64 Audio a silver color replacement instead.
The stock cable is flexible, light, prone to microphonics, but I think part of it has to do with ADEL module/port since even with a decent isolation you are still well aware of surrounding environment.  Don't expect earplug like isolation.  I tested it with a few of my other replacement cables that dead quite with other IEMs, and still hear some microphonics.  After awhile of using stock cable, analyzing A12/U12 sound signature, and picking up details of how it pairs up with different sources, I found that stock cable is great with bright sources but the neutral-warmish signature of this 64 Audio flagship becomes a little darker and smoother with warm sources, especially my smartphone.  This is purely a subjective opinion, but after cable upgrade I wasn't able to go back to using stock cable.
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I always find the subject of replacement cables to be controversial topic.  Some people either don't hear the improvement or convince themselves there is no improvement without even trying a cable swap.  Others do hear the change but expect a significant improvement based on the price paid for the cable without realizing they’re dealing with diminishing returns.  I'm not here to argue with people, but rather to offer my impression based on what I hear with cables I have in my review possession.  There are a number of different aftermarket cable makers with products that could yield the same level of sound improvement, but I only have access to Linum and Whiplash cables, thus offer my opinion relative to these products.  Besides, Whiplash manufacturers cables in high volumes to distributors around the world, and it’s easy to find them even on Amazon.
Switching to Linum BaX makes cable completely disappear since their wires are super thin.   It also tightens the sound and brightens the tonality, especially in the treble region where I hear more sparkle after the upgrade.  But at the same time it pushed upper mids a little more back.  After closer listening, I determined that what I hear as mids being pushed back is actually a change in soundstage where depth has been improved but at expense of upper mids (especially when it comes to vocals) being pushed more back.  I wasn't too crazy about this sound change.
Next I switched to Whiplash TWag and TWau cables, and that's where the magic started to happen.  With TWag (pure silver conductors) the sound becomes tighter, bass is more articulate and with a better control, lower mids are a little cleaner and leaner, upper mids are still balanced but now a little bit sharper with improved retrieval of details, and treble is a little brighter, crispier, with improved definition and a little more airiness.  The holographic expansion of the soundstage is taken to another level with more width while still sounding realistic and not 3D-artificial.
Stepping up to TWau (gold plated pure silver), I hear a similar improvement where sound is tighter, bass is more articulate, especially a noticeable improvement in sub-bass texture, lower mids and upper mids improvement is similar to TWag but sound becomes a touch smoother and more analog while still being detailed and highly resolving.  Treble improvement is the same as TWag, and I hear the same soundstage width improvement.  If comparing TWau to TWag, I hear TWau adding a little more texture to the sub-bass, making mid-bass a touch less aggressive, balancing out upper mids by bringing them a little bit more upfront.  To my ears, both TWag and TWau introduce a noticeable improvement over the stock cable.
TWag with a standard 2pin connector and TWau with OM (over-mold) 2pin connector with spacer mod:
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Since I had the opportunity to test both Custom A12 and Universal U12 replacement, I was able to capture a number of detailed photos and took plenty of comparison notes.  Obviously, it's the same internal 3-way crossover design with 12x BA drivers partitioned in groups of 4 lows, 4 mids, and 4 highs.  Also, both are featuring a 4 bore design where 3 sound tubes from each group lead to the tip of the nozzle and a separate bore forms a return path to ADEL module.  In terms of a spec, both are rated with 16 ohm impedance, 115 dB sensitivity, and 10 Hz to 20 kHz frequency response implying low end extension.  Last but not least, both shell types use hypoallergenic hard acrylic material which is more common with Custom models, but also used in Universal one here as well.
As I mentioned before, Universal model is rather generic looking, all black with a long extended angled nozzle.   You don't get a chance to see the internal arrangement of drivers, and there is no option to customize it, but the shape of the shell is very ergonomic and surprisingly not that big.  On the inner side the corners are all rounded and not for a second I felt uncomfortable wearing these for hours at a time.  Don't expect to fall asleep wearing these with a head on the pillow, but they are lightweight and comfortable enough to disappear in your ear during extended use.  Of course, this is very subjective and also relative to individual ear anatomy, but as a reference - I wasn't able to wear SE846 for more than 10-15min at a time due to their size, while U12 fits my average size ears like a glove.
There is no color coded L/R indicator, often found in other monitors with red on the right side and blue on the left side, and inside you will find etched U12 model number and S/N.  Since shells are not symmetrical, there is no way to mix up the fitment which always goes in one way with wire up.  On the outside, the faceplate has well defined corners and "ADEL" label on the right side and "64 Audio" on the left side.  Also, in the corner of the shell opposite of the nozzle you have a cylindrical cavity for removable ADEL module.  The location of the module is very convenient especially when you use MAM units to reach the adjustment crown with ease.  The nozzle is not too thick or too thin, has 4 evenly split bore quarters, and the body of the nozzle itself has a slightly thicker band in the middle with "12" label which helps to keep eartips from sliding off.
While U12 comes with a set of S/M/L Comply eartips, you are not limited to try whatever fits your the best.  Having a lot of different IEMs in my collection, I went through to find the most comfortable silicone tips which give me the best seal.  One thing to keep in mind during tip rolling (going through selection of different eartips), if you are playing with narrow bore tips like those found with Westone or Shure - you can stretch them to fit, but a narrow bore opening will cover the tip of U12 nozzle and it will definitely affect the sound.  If you want to keep the sound close to the intended signature, you need to select eartips that won't obstruct the nozzle.
U12 Design.
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U12 next to UM Maestro and Noble Savant.
U12 Fitment.
Looking at A12 design is a whole different story.  Obviously, you are now in control of how the shell and the faceplate going to look, and able to clearly see the arrangement of drivers and crossover components through a transparent shell color I chose for A12.  So many times I used to wonder about other IEMs/CIEMs if they use dual or quad BA modules in order to fit such a small space inside of the shell.  Here, I was looking at a shell size which is on par or even smaller than some of my other 6-driver CIEMs, and yet I'm able to see 12 distinct drivers and a nice size tantalum capacitor and a small thick film resistor.  The room inside was fully utilized without wasting a single pocket of space, and that also included a relatively large cavity with ADEL module inside.
The workmanship of soldered wires interconnecting every driver and crossover components was impeccable.  I didn't see any bubbles or imperfections; the shell looked great on the inside as much as on the outside where everything was smooth.  The model number and S/N were printed in red/blue colors to distinguish Right/Left sides - useful since CIEMs could be a bit confusing from the first look until you try to jam them in your ears (the difference is more obvious with universals).  The tip of the nozzle was smooth, rounded with 4 separate bores, including one going to ADEL module, and other 3 going to corresponding low/mid/high BA clusters.
Obviously, A12 model is based off a custom impression where 64 Audio scans it in and manipulates the trimming digitally.  If something doesn't work, you have 30-day re-fitment grace period.  Once the shell is in your ears, the fitment is nearly flush without sticking out too much, though I wouldn't recommend sleeping with these on.  Though I had a few fitment issues with A12, it has nothing to do with 64 Audio and rather a weird anatomy of my left ear canal where it starts off wide and then quickly turns and narrows down.  I'm quickly coming to a conclusion that Customs might not be my cup of tea, and I was very grateful for 64 Audio allowing me to continue with my review using Universal U12 replacement.
Design - A12
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A12 next to Westone ES60.
A12 Fitment.
ADEL module.
I did talk about the basic principle of Stephen’s ADEL technology in the intro of my review, but in reality I have a feeling that a lot of people will overlook the benefit of ear health and will be interested only in sound improvement.  It’s a sad reality where we don’t realize the irreversible effect of ear damage, and then wish we would have done something different when we had a chance.  Fortunately, ADEL technology implemented in 64 Audio headphones doesn’t bring down A12/U12 to look like your grandparents hearing aid, and it’s actually a cool looking functional accessory that compliments the design of these TOTL monitors.  At the same time, it can create some confusion because of wrongful expectation of what exactly it does.
Let’s start with a default ADEL auto-module.  With a module out you have an open path from the faceplate of the shell through to a separate bore in the nozzle.  Regardless of A12 or U12 design, with module removed the sound becomes an open back headphone with a significant low-shelf filter cut.  Obviously, 64 Audio headphones were not intended to operate without ADEL module.  With auto-filter back in, you get back the closed back isolation, and your bass performance - the sound goes back to normal.  But what is normal?  I will get into a more detailed sound analysis in the next section of the review.  But in theory, the benefit of ADEL module can only be analyzed if you have side-by-side A12/U12 with and without a module and completely sealed path from the faceplate to the nozzle bore, or if you simply close the pinhole opening of auto-module.
With a default ADEL module I can only analyze a sound signature as is and can feel the subtle change in sound pressure as I put my finger over the pinhole opening.  Also, I noticed that I can push the volume higher without feeling uncomfortable during the listening.  A12/U12 are not bass shy, and usually pushing the volume higher with other similar sound signature IEMs will result in throwing off the balance of the sound, while in here I felt the change was more linear while still maintaining coherency of the tuning.  At the same time while reading comments from other A12/U12 users, I quickly came to a conclusion that effect of auto-module might have a slightly different response depending on our ear anatomy.  Just think about it, we have different ear canal shape, different level of acoustic reflex, different hearing sensitivity, etc., and in my opinion the response of ADEL module will vary accordingly.
And that is where the manual adjustment module (MAM) comes into a picture.  I was fortunately to get a pair of MAM modules directly from ASIUS Tech, and that really opened up my ears and answered a lot of the questions.  Now, instead of dealing with auto-module which going to respond to your individual ear canal anatomy, you are in control of fine tuning the effect.  To my ears this effect varied a little bit between A12 and U12 because A12 has a perfect seal with maximum low end response, while U12 low end response was dependent on eartip selection.  But in both cases, I can hear and confirm with my measurements that changes in both A12/U12 happen in sub-bass and mids bass region with sound being attenuated down as you start turning the MAM crown dial from closed position.  Closed position gave me an exact sound as auto-module, but opening it up gives you a reduction in low end response as you’re getting closer to fully open position, and then bass goes a little back up as you get all the way down to a fully open position.  Btw, the adjustment is done in a very clever way where left module is turned counter-clockwise and right module is turned clockwise so you are turning them both in the same direction when adjusting simultaneously.
The current MAM module has continuous tuning, and the sound change really takes at least a quarter or more of a turn to hear the difference, so there is no worry that you will throw off the tuning by accidental bump.  Also, the audible change starts earlier in A12 versus more toward the end with U12, which I assume is due to a higher starting level of low end impact (due to superior A12 seal) where it creates a more noticeable tuning contrast.  But the most important thing here, I’m NOT talking about EQ adjustment where you turn the knob to reduce a specific low frequency band, but the actual reduction of low end intensity where you no longer feel the bass pounding on your eardrums and instead hear an articulate low end response.  With that change, sound becomes more transparent and more open (improved soundstage perception).  It reminds me of a subtle effect of opening windows where the sound doesn’t feel as congested inside of your ear canal.
I don’t expect everybody to hear the difference on the same level because our ear anatomy and hearing perception is different, but after spending many hours with U12 (my adventure with A12 was much shorter) – I can confirm that it’s not a placebo effect of a new toy syndrome, this is a real deal.  It got to the point where switching to other IEMs and CIEMs felt like something was missing, lacking some hidden dimension.  The biggest effect of MAM module for me was in fine tuning of the low end response.  If you are a certified basshead where you want to maximize the low end impact – stick to auto-module and either go for a perfect seal of A12 or switch to Comply foam tips with U12 (or just maximize your bass pleasure with A8/U8).  But if you want a more balanced sound using A12/U12 – MAM module is the way to go, especially if you are using Universal U12 model where you can adjust the module and switch between different eartips to control the seal.
ADEL (auto-module)
ADEL (MAM: manual adjustment module)
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Sound Analysis.
I let both A12 and U12 burn in for 70+ hours, though there wasn’t as much of a noticeable difference except for the first 10-15min out of the box.  While using STOCK cable in both cases, I found A12 sound to be tilted a little toward L-shaped signature due to a tight seal having a noticeable effect on scaling up mid-bass quantity.  U12 sounds more balanced due to a lesser bass quantity since a seal is controlled by selection of different eartips where I was never able to reach the same level as with a custom model.  Both have a neutral smooth sound color leaning more toward warm natural tonality.
Both A12 and U12 have a deep textured sub-bass extension layer underneath a warm analog mid-bass punch in a perfect balance without overpowering each other.  The bass is rounded, warm, with attack that is not super fast and decay that is long enough to turn the low end BA quad into a more dynamic driver performance.  Bass has a nice control but not very tight.  It provides a beefy slam with an authority not typical of BA performance.  Bass has a well executed musical analog quality with layered details and natural timbre.  Once you start adjusting the MAM module, you start to appreciate the effect where all of a sudden bass becomes more transparent and you no longer feel the visceral effect of the rumble but rather hear a multi-dimensional layered performance.  When I took my measurements, I was definitely able to see the effect of bass reduction below 300 Hz which affected both sub-bass and mid-bass, and that was not a bass reduction typical of EQ adjustment but rather a reduction of bass intensity which sounds more relaxed to my ears, allowing me to raise or to lower the volume without affecting the linear coherency of the low end.
Mids didn't vary much between A12 and U12, and also MAM module adjustment had a little effect except for adding a level of subtle transparency.  Here, the lower mids have a full warm body that gives sound a lush analog feeling without being veiled or muddy.  Upper mids are organic, smooth, open, and also very clear and detailed.  This clarity and level of details is far from what I'm used to hearing from my other smooth/warm headphones.  When it comes to mids, often manufacturers make a decision to either go for a brighter detailed tuning which can make sound harsher or to scale back with a smooth organic sound where retrieval of details can suffer.  With A12/U12, 64 Audio kept mids balanced and linear, without any peaks or dips across mid-range frequency region.  You will hear a high level of clarity and smooth organic details without a single hint of sibilance or harshness.  Vocals are smooth, natural, full of energy, and come through with a high level of details despite an overall neutral-warm tonality.
Treble is definitely not the biggest star of the tuning due to it being scaled down, but it's done in such a tasteful way where it's still clear and has a great smooth definition, just not very crisp or bright.  Often when other manufacturers go for a smooth organic sound where they chose to roll off treble, you will notice right away muted details in upper frequencies.  Here, 64 Audio completely avoided the sibilance region, and instead put emphasis (slight boost) into upper treble to add transparency and airiness to the sound.  Don't expect long extended crashes or resonating percussions, but all the instruments sound natural with a very realistic timbre.
I don't usually listen to a lot of acoustic music, but I made an extra effort to analyze how effortlessly A12/U12 delivers the audio details where thanks to the texture and the rumble of the bass the sound has a full organic body, where thanks to a smooth detailed mids the vocals, both male and female, sound very natural and full of energy, and thanks to a clear well defined smooth treble the instruments timbre was accurately represented without missing anything.  I often wonder if extra drivers really add to the tuning or just part of the marketing hype.  There are some great IEMs/CIEMs that take full advantage of their dual or triple or even quad driver configuration.  And there are some others where 5 or 6 driver tuning could have probably been as accurate using fewer drivers.  Here, while listening to A12/U12 and analyzing sound details, you can zoom into every region of the frequency range to hear how layered, accurate, and articulate it sounds thanks to a 3-way crossover partitioning of quad lows, quad mids, and quad highs working together in one perfect harmony with a great coherency between the drivers.
The sound is very dynamic, and has a high level of transparency.  For a smooth sound with neutral warmish tonality I was quite surprised to find an excellent level of separation with a distinct layering effect between instruments and vocals.  From my experience, warm smooth signature often results in some sound congestion, especially when it comes to a more complicated music passages.  Here, any music genre I threw at A12/U12, regardless if it's pop, rock, EDM, jazz, instrumental - everything retained a perfect separation and layering.  The soundstage was another star of the show with a holographic expansion in all 3 directions.  The imaging was definitely on a 3D level with a very convincing placement of instruments and vocals with a nearly perfect pin-point positioning.  Again, I would have expected this kind of a performance from an analytical type of tuning, so it came as a big surprise from a smooth and warmish tuned pair of monitors.
Comparison to other IEMs/CIEMs.
U12 vs Maestro: Maestro bass is not as articulate, sub-bass texture is not as well defined, lower mids are leaner, and upper mids are brighter and harsher and not as organic, treble is brighter and crispier, a little more splashy and with more airiness.  Soundstage is narrower, while depth/height is the same.  Overall, U12 sounds smoother, more analog, and more transparent, while Maestro is harsher and more analytical, and less organic.  They both have the same level of detail retrieval, but U12 is more natural.
U12 vs ES60: ES has a very similar smooth detailed organic tonality, but low end is not as tight as U12 and has less impact with more rolled off sub-bass, lower mids are similar and upper mids are a touch brighter in ES.  Also ES treble is a little bit brighter and has a slightly better definition, but overall has the same level of airiness.  The transparency and the level of layering and separation are very similar.  ES soundstage is a little narrower, while depth/height is similar.  The main difference here is ES being a little more neutral and with less low end definition, while U12 having a far superior bass in both sub-bass extension and texture and mid-bass impact and also a wider soundstage.  Another thing to keep in mind is that you can have A12/U12 in either universal or custom fitment, while ES60 only comes in custom.
K10U comparison will come soon; review sample wasn’t available during this write up.  Also, it made no sense to compare to any of my other IEMs since for example W60 is smooth and warm, but sounds veiled in comparison, doesn't have the same low end impact, not as transparent or dynamic, and can't match layering and separation due to sound being a bit too lush.  UM Pro 50 has a great low end impact, but fails to match details of mids and extension of treble, and nowhere near the soundstage expansion.  Ei.xx has a great smooth sound and excellent bass impact, but it wasn't as tight or as articulate, and mids were far from being as detailed, sounding more veiled in comparison, and the same with treble lacking airiness.  Miracle wasn't able to match the low end impact or the organic smoothness of mids, though it was more superior in treble, but overall not as transparent or detailed.
Pair up.
PAW Gold - reference quality dynamic detailed sound with excellent retrieval of details, amazing soundstage expansion, and very articulate low end.  LPG was my main source during sound analysis of A12/U12 and comparison to other IEMs/CIEMs.
L5 Pro - excellent pair up with a dynamic smooth layered sound, great low end impact (among the best in this case), impressive soundstage expansion, excellent retrieval of details.  Also tried it briefly with the new L3 in balanced mode and soundstage holographic expansion just explodes in 3D quality.
X7 - the sound is very dynamic, crisp, and with high level of detail retrieval.  It does take away a bit of an analog smoothness in comparison to PAW Gold, but the overall sound was a bit more balanced, especially with a stock cable.  w/AM2 module sound has more body, regains some of the smoothness, and improves soundstage expansion.
DX80 - smooth detailed sound, deep low end extension with an excellent sub-bass texture and tight mid-bass punch, amazing soundstage expansion.  I was quite surprised with this pair up, especially enjoyed the soundstage expansion.
X3ii - warm detailed punchy sound, surprisingly a decent soundstage expansion, deep textured sub-bass, not as high level of transparency or layering/separation, but still great pair up.  It serves as a good example that you don’t need $3k+ source to make A12/U12 shine.
While in so many situations DAP can make headphones shine, here I found an opposite phenomenon where U12 actually made some of my DAPs shine.  Regardless if it was summit-fi or mid-fi DAP, the sound was always smooth and detailed and expanded to the maximum potential of the source.  I can even go as far as saying that despite their detailed tuning, A12/U12 are quite forgiving where I was listening to a few poorly recorded songs on my Galaxy Note 4, and they didn’t sound half bad.
Pair up (A12 + L5Pro, U12 + LPG)
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We all know that listening to music is good for your body, your soul, and your spirit.  Now, you can also add to this list - your ears!  Before receiving A12/U12, I have done my homework reading about ADEL technology and Stephen Ambrose research work.  If you have a minute, search YT for videos of how he helped some people with deaf ear to hear for the first time.  I was a bit fixated on the effect of this technology before I put these monitors in my ears.  But once I hit Play, it was all about the genius of Vitaliy and his tuning of A12/U12 flagship.  I forgot about ADEL module until I was ready to test MAM – that’s when I discovered the effect of Stephen’s diaphonic lens tuning.  Will A12/U12 sound good without ADEL?  In my personal opinion, there are dozens of flagship IEMs/CIEMs that sound good without ADEL technology and you would probably never find out what’s missing when you take their sound tuning as is.  Would 64 Audio have a hit without ADEL module?  I have no doubt they would, because it’s all about sound tuning and A12/U12 got it with a driver coherency where all 12 BAs melt into a sound of one large dynamic driver with a smooth high resolution performance and spatial details that will sound great from most of the sources, even your smartphone.  But adding ADEL module to this equation is like going from Universal to Custom where the sound is fine tuned and customized to YOUR ears specifically, and it makes listening to music not only enjoyable but also safe.  At the end of the day, you get the benefit of both and if you compare 64 Audio prices to their competitors (or wait for holiday specials when they offer up to 20% discount) – you will quickly realize that ADEL technology comes as a free bonus with these first class TOTL monitors.
@twister6. When you state "well aware" of your surroundings even with a decent isolation and fit, do you mean that the ADEL IEMs do not isolate as well as other standard IEMs? Is isolation on par with open back headphones or maybe on ear headphones? It seems that if they don't isolate well, then a user would end up increasing the volume in a noisy environment which would effectively negate the benefits to some extent of the ADEL module. In any case, I am just trying to quantify the amount of isolation provided by the ADEL IEMs based on comparison with other IEMs or headphone types. I have been seriously considering the ADEL IEMs since I too suffer from some inner ear problems during high allergen seasons, but I would need very good isolation due to a noisy work environment- I.e. Constant fan noise on the magnitude of 75-80dB.
@ModMax - sorry man, ADEL probably not going to fit your needs.  IEM/CIEM isolation is often a result of a perfect "vacuum" seal, which also can create a pressure, etc.  ADEL filter releases this pressure but as a result you will have to compromise your "perfect" isolation.  At the same time, raising the volume with other IEMs/CIEMs makes listening intolerable, while in here I can tolerate a lot higher volume without feeling but rather hearing the sound.
Excellent Review, as always especially the comparator & synergy portions.

Canyon Runner

500+ Head-Fier
Pros: Absolutely amazing sound quality, Build is near perfect, Fantastic customer service, Tunable
Cons: Out of some people's price range
I gave a follow-up on my review below the original post with a happy ending.

I had issues with the Automatic ADEL modules that came stock with my A12s (as you'll read below), but I'm going to keep the original post in case new customers get their IEMs in the mail and have the same issue my ears did. You will be able to read my frustration, possibly relate if your ears are like mine and are hearing all kinds of noises in various settings and don't know what to make of it.


This is my first audio specific review, so bare with me. Earlier this week, I received my pair of A12 Custom IEMs from 64 Audio. I demoed pretty much every flagship IEM at Rocky Mountain Audio Fest in October and these were what I ended up with.

After many of you might be able to relate, the waiting for custom IEMs can seem much longer than a matter of several weeks. I actually had them brought to me at work by a family member once they arrived at the house, I couldn't wait to inspect and listen to them.

The case they come in is nothing to write home about in the looks department. Hard black plastic with an etched logo and your name at the bottom, gloss black in matte black. It does feel like you could very confidently drop it down a flight of stairs without worry and thats what actually matters. Inside each IEM gets its own little compartment and posts to wrap the cable around, along with a shirt clip. Not really fancy but very functional and well thought out.

The craftsmanship is fantastic, much better than my JH Audio Roxannes (I had to send them back for repair once one of the faceplates partially separated from the body, they reglued it and polished the pair...and I promptly put them on the used market). As you can see in the picture, I got my A12s in clear on clear so I can see all the guts. There's a partial finger print on one of the drivers and a very small bubble in the acrylic on the body, that's an absolute minor detail but keeps them from perfect construction.

The sound: This is a tough one. My first night with them was amazing then totally frustrating. I'm not going to get super in depth about the sound signature, mostly because I know others can put it much better with fancy descriptions, I'm not the best at that. I will say that they are utterly fantastic. I have them paired with my AK120ii, I've used a wide range of quality files. From DSD to your standard not-so-good mp3s and as you'd expect, they're really revealing. Even then though, they're pretty forgiving. The poor quality stuff still sounds very nice, not amazing but still very enjoyable. When you play better recorded files, they really REALLY come to life. So its really a matter of solidly good, even at the worst, then only gets better from there.

The sound is very full bodied and balanced. That's really the best and simplest way I can put it. It's a very airy sound that I've never heard from an IEM before, most of that is due to ADEL (which I'll get to in a minute). The tone is very rich and lifelike. The sound stage they offer is massive, I've never heard IEMs that produce a sound stage similar to top tier over-ear headphones before, it was a very large part of why I picked A12s instead of the very sweet Noble K10s. IEMs tend to focus the music in what I would say purely in your head, almost like your head is empty and that's just where it's all going on. However ADEL helps the A12s really bring that out a bit, rather than just between your ears, its sorta like ears plus 6 inches outward. Sorry if that sounds very strange but it's a weird concept to try to describe.

Everything about the sound of these is the way they should be, yeah that sounds vague but everything is in it's place. Nothing over shadows the other. The bass is very punchy and powerful when it's called for, like a giants hand popping out of the darkness. Pops out and disappears just as quickly, not lingering and bleeding over. The mid range sounds just right, I can't say I'd change a thing. The highs are still smooth and not ear piercing, cymbals of drums have a very lifelike lingering effect.

With all the sound and performance out of the way, here's the thing. And it's a BIG thing. These have the new ADEL technology, which in a nut shell is designed to let out sound pressure between the drivers and your ear drum to be less harmful to your ears. It does that by having a 5mm metal rod about 2mm thick, riding on dual O-rings, being pushed by the sound pressure. It's supposed to act like a secondary ear drum, absorbing/releasing the pressure like a second ear drum. Frankly, I don't know about all the claims for hearing protection and they haven't released any scientific data to back up that claim either. It VERY much helps with widening the sound stage though, it's the magic touch that separates the ADEL equipped IEMs from competitors. ADEL helps give everything that airy sound and it really helps cross that gap that IEMs never could before, sounding like an over-ear headphone. When I thought about what IEMs sound similar to A12s, I really couldn't. The only IEM that I felt sounded as good, in a different way, was the Noble K10. What does the A12 really sound more like? Like the big boy over-ear headphones. Personally I thought they were far more similar to HiFiMan HE-X (the "budget" HE-1000s). This is a great and horrible thing...

Like alot of IEM users, my listening is mostly done on the go. On the way to work, shopping, at work, walks, etc. This is a big problem for these, why? Just like an open back headphone, there is very little in the way of isolation. This was a BIG shock to me on that first night. When I demoed the A12s at RMAF, you're just sitting there calmly, not moving. So while these things really really sing in a quiet setting, they are a whole different animal in the real world. I went out for a walk that first night and had my image of the A12 pretty shattered. As I walked around town on a nice evening, I kept hearing this THWAPP THWAPP THWAPP noise during low-medium volume sections of songs. I thought maybe the cables were bouncing around as I walked, they weren't. Perhaps the seal in my ears were breaking? They weren't. I touched the ADELs and it went away instantly. You know what it was? My shoes on the pavement. As the ADELs were moving around doing their thing, they were letting in the sounds of my feet. You can also imagine how irritating that is.

One thing that hasn't seemed to be factored into the ADEL design is, your body moves. While ADEL achieves its goal and the A12 really performs when you're sitting calmly and not moving, the movement of your body when you're walking (or whatever else you might be doing) throws the whole process off. Sorta sounds like somebody waving their hand in front of a speaker, it's inconsistent and really noticeable. At low volumes or between songs, you can hear the ADEL moving around on their own, it sounds just like having water in your ear. Tipping your head or even walking.

I thought maybe keeping the ADEL closed (through an adjustable module which is in development) would maybe be the winning touch but even just holding the ADELs closed with your fingers shows otherwise. The sound stage shrinks dramatically and the treble really falls flat, they really tuned to ADEL being there.

What 64 Audio has really done here is created an open back headphone but in IEM form. When you think about where you listen to over ears and how they behave, it lines up perfectly. Would you take an open back with you on the bus? Probably not because all that extra noise bleeding in (not to mention the obvious bulk and probably needing an amp). So if you think about these as open back headphones, it makes far far more sense as to how they behave. For myself, if I had read that on head-fi from other owners, I know it really wouldn't fit how I listen to IEMs.

These are really perfect for an engineer sitting in a studio that doesn't want bulky over ear headphones, or those calm nights drinking tea, but NOT for leaving the house like you would any other IEM where isolation is a requirement. I'm still going back and forth on what to do with my pair, I have already spoke to the 64 Audio about all of these things and I have the option of a refund if we can't come up with a solution. 90% of my listening is done on the mobile side of things and I feel that trying to plug off the ADELs to gain isolation can be seen like trying to take a fully built GT race car and putting street tires on it to try and make it a street car. It just doesn't really work, it's tuned to work a perfect system and do one job in one specific setting. It does that one job amazingly well, trying to convert it to something else leads to very poor results.

...but they sound so damn good in a quiet setting that I don't know if I'm going to be willing to part with them, even as unpractical as they may be. They truly are astonishingly special.

As for scoring, when you use them in their environment they easily get a 5 star rating. However, most IEM users actually want to take their toys on the go with them, these aren't suited for that...at all. So I don't know if they should be penalized for that or not, much like you wouldn't ding an open back over-ear headphone for not being friendly for mobile use, that's what makes this tough. So if you use them at home, 5 star, but try to use them as a portable option 3 stars? It can be done but I find the lack of isolation and microphonics insanely irritating. Snaps you out of your nirvana like listening zone instantly, like being woken up by a near by wood pecker. I rather use my cheap Shure SE215s for portable use than the A12s, that should say something.




Updated 12.5.2015

Ok, so I ended up reverting back to my Shure's for a week or two as I talked with 64 Audio between email and phone calls. Right off the bat I want to say that dealing with 64 Audio's customer service was never a pain or stressful, they're a great bunch of people and it was honestly a big reason I went with them originally after getting to talk to a number of company heads and engineers at RMAF. They just have the vibe of wanting to share their product with people and hoping you like it as much as they do, rather than "we are the company, you are the customer and you'll give us however much we demand for it". Very willing to make sure their customers are totally happy with their product, no matter what.

As I have mentioned, I kept the A12s in the case for a while, maybe taking them out for an hour or two per week for a listen, then I'd just get frustrated. They sounded so good when they were in their element but I couldn't handle the hand-waving-in-front-of-speaker effect or woppy sound I'd get as I tipped my head. I was very close to sending them back and ordering up a pair of Noble K10s. VERY CLOSE.

64 Audio put me in touch with Stephen Ambrose, who is the inventor of ADEL and I was able to spend the afternoon with him & his wife. We went over all the video explanations of ADEL that many of you have probably already seen (if not, youtube them), as well as talking about everything I had been experiencing with my ADELs. For lack of better wording, it was a perfect situation of finding a problem with somebody's product, talking about it in detail with them, then having a perfect fix. (We also tested my Auto ADELs to make doubly sure they weren't defective, they weren't)

The Solution...

Manual ADEL modules. Those of you who had been following the kick starter project, knew that was a thing (and suggested that would be the fix, but since they aren't currently on the available, it didn't help much, even though those that suggested were absolutely correct!). They were made before the automatic ADELs (that now come with A & U Series), this happened partially because a number of people felt they might not be able to dial-in the manual ADELs for their ears perfectly, therefore easy simple no-touch-necessary ADELs were put in the IEMs. This is the perfect situation for alot of people, I'm not one of them. Maybe you aren't either. I've even been told by other customers that they don't hear the same microphonics as I have, therefore it must all be in my head. This isn't the case.

Here's the deal. Each ear is different obviously, not just person to person, but your left and right. Each has a different design of canal, making pressure levels and their changes more noticeable in certain ears. My ears are much more sensitive to that pressure, my right one more than the left. This is why I was hearing the ADEL flap around more in my right than my left, the pressure was different. Swap the ADEL module themselves from IEM to IEM and it doesn't matter, same response. I would plug the hole on the ADEL and it'd stop. My assumption of the ADEL bouncing around on it's O-Rings up & down were wrong, the pressure was just letting them move way more than what's pleasing, almost like a bottoming out speaker (sorta).

With the manual ADELs, I get NONE of the annoying downsides of the A12s. I actually haven't taken the A12s out of my ears since we swapped in the manual ADELs five hours ago. You are now able to adjust how much the ADEL is absorbing by dialing them tops in and out, much like the top of an adjustable shock absorber. As you dial, you can hear an audible click of a magnet inside snapping back into place, allowing you to count and keep track of your settings. Like an all-season tire, jack of all trade/master of none, the automatic ADEL does what most customer and their ears would want without being told and doing a pretty good job at it, but the manual ADEL lets you dial in specifically what you want out of them. Or to stick with tires, being able to swap from snow tire to summer tire on the fly, while matching the pressure of each ear.

These are now top-notch sounding IEMs, regardless of sitting calm at your desk OR out around town on the go.

They look great man, good job.
In your description of what you do for a living you have "Testing new goodies, helping with development and assembling ADEL modules for Asius Technologies" - does that mean after your experience you got hired by Stephen and working for 64 Audio now, making ADEL modules? :)  That sounds pretty cool!!!
Canyon Runner
Canyon Runner
I started working with Asius after hours (I manage a collection of 400 collector cars, for my day job..basically all day with IEMs in), assembling modules..starting like 2 weeks after I got my MAMs (Stephen was in China for 10 days, hence the delay). Then it sorta progressed from there, he'd ask for my input on ideas, or just ask me to come up with something for whatever challenge had come down the pipeline, thoughts on a prototype, how it sounded, etc. Then the more I opted to take on any challenge thrown at me, naturally I got more and more involved and was able to start explaining the technology to other customers/head-fi users. Shortly after that, they invited me to come and work CES in Vegas with them earlier this month at the Asius/64 booth.