64 Audio A10 - Reviews
Pros: Top-Class Sound Quality, Balanced Tuning, Fatigue-Free Sound, Imaging, Instrument Separation & Layering
Cons: Sound-stage Depth Could be Better, Needs a Good Source to Shine
I purchased the A-10 Custom IEM from 64-Audio directly, as a part of the ‘Audio Enthusiast Program’, that was run by 64-Audio in March 2016. The terms of this promotion were: ‘the buyer will be offered a 15% discount off the price of any ADEL IEM at the time of purchase, under the agreement that, the buyer promises to write an honest, unbiased review’.

A-10 is a 10 Driver Custom fitted IEM from 64-Audio, featuring the ADEL Technology. Per 64-Audio's website, this is a reference monitor, suitable for Studio Use, Critical Listening and Audiophiles.
DRIVERS: 10 x Balanced Armature Drivers – 2 x Low, 4 x Mid, 4 x High
CROSSOVER: 3 Way Passive Crossover
SHELL MATERIAL: Hypoallergenic Hard Acrylic
BORES: Quad Bore (4)
CABLE: 2-Pin Generic Braided Cable with 3.5 mm Plug
RETAIL PRICE: $1,799.00
PRODUCT PAGE: https://www.64audio.com/product/1964-A10-Custom-In-Ear-Monitor

Just within a few months, after I bought a set of Sennheiser IE80 and Fiio X3ii, I wanted to upgrade to a High-End setup. I decided to take the Custom IEM route and, started to look on Head-Fi. Kaye2 brought the 64Audio ADEL IEMs to my attention. I had a chance to demo the A-10 and the A-12 through 64-Audio’s Demo Program. After demoing both, I ended up choosing the A-10.
REASONS WHY I CHOSE 64-AUDIO: U.S Based (I am currently located in the US), 15% Discount and Excellent Customer Service (from personal experience during the Demo Program)
REASONS WHY I CHOSE A-10 IEM: Top-Class and Fatigue-Free Sound, Balanced Tuning and, Other Strengths I mentioned in the PROS Section
I am a 27 y/o male. My hearing sensitivity ranges from 24 Hz to 17 kHz. I listen to a variety of genre (Rock, R&B, Acoustic, Instrumental, Classical, Blues and Pop). Less than a year ago, I used to prefer a ‘V’ Shaped and Dark Tuning in headphones. Lately, I have come to prefer a more Balanced Tuning. because of my life-style and convenience factors, I only own and use IEMs.
SOURCE GEAR: Mojo, Fiio X3ii and iPhone 6
FILE FORMATS: 16/44 FLACs and 320 kbps MP3 (16/44)
MUSIC GENRE: Multiple and Varying

64-Audio now employs a 3-D printed process to make the shells (Interesting Fact: Even their Universal Versions are 3-D printed with acrylic material and are not plastic/polymer molded). I opted for a simple design: Charcoal Shells and Face-plates and No Logo or Art. The build feels solid. I have not seen many other Custom built IEMs, so I do not know how it compares to other manufacturers. The finish is excellent. The buffing really provides a smooth reflective surface that can be seen in some of the attached pictures.
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The cable is the generic braided cable that looks similar to the cable, which most manufactures use for their Custom IEMs. By default, 64-Audio goes with recessed sockets, for their A series Custom IEMs, unless the shape/size of the ear doesn’t permit it, in which case, regular sockets are used. IEM termination of the cable is the regular 2-pin with memory wire and tubing. The 'Y' split is just a, simple heat-shrunk piece of tube. The source termination is the conventional right-angled 3.5 mm plug. I do most of the listening at my desk, and have not experienced micro-phonics from this cable.
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Typical to any custom IEM, these provide a glove-like fit and, I am able to get a good seal on both sides. The comfort is also very good, but it took me a week to get used to this tight fit. The smooth curves and surfaces ensure easy insertion and removal. With the B1 Modules rated at -10dB isolation, the isolation is fairly good on these IEMs. Once again, since most of my use is indoors at my desk in a noise free environment, the isolation these IEMs provide are sufficient for my use.  
The IEM comes with just the essential accessories. Nothing more and nothing less. 1 x Hard Case, 1 x Dehumidifier, 1 X IEM Cleaning Tool and 1 x Shirt Clip. (The picture below does not show the Dehumidifier and the Cleaning Tool. The Dehumidifier, is still inside the protective wrap, it came in and, I seem to have misplaced the Cleaning Tool). The most interesting accessory is the case. It is built like a tank and is very functional. The IEMs itself will be placed inside a secured chamber that is lined with rubber for protection. There is a center island, around which the cable can be wound and, there are sockets to secure the 3.5mm jack in place. These sockets also act as ear-tip holders (will come handy for Universal IEMs). There are also sockets to hold 2 pairs of ADEL modules. There are indents and places to hold the dehumidifier, the shirt clip and the cleaning tool. Although very functional, it is not practical for my everyday use. I just like to wind the cable around my fingers and put it inside a clam-shell box and so I bought a Pelican 1010 case to store and carry my A-10.
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A-10’s sound, in short, can be described as balanced, smooth, musical, airy and laid-back. There is a lot of air in the sound and, this air has a significant impact on how the IEM sounds/presents its sound.
A-10 has a balanced tuning, with an ever-so-slight boost in the low-end, just enough to add ever-so-slight warmth and musicality to the sound. 64-Audio markets the A-10 as a neutral IEM. Although the A-10 sounds balanced, to my ears, these do not sound perfectly neutral.
I love the bass on the A-10. It is tight, quick and has a lot of quality to it, than mere quantity. The low-end extension is good for a BA. The sub-bass has nice rumble and texture, but doesn’t go/dig deep. To get a feel of the bass texture, one must listen to the Radioactive track by Imagine Dragons. The reverb that I hear is amazing. The air actually helps the bass to offer this feeling of reverbs and texture. The mid-bass is very clean and, does not bleed into the mids. Zero Bleed. Remember, this is an ADEL module fitted IEM, and the ADEL module’s effect is prominent on the bass. You lose out a little bit on the slam and authority, but on the bright side, you get a well-textured and a fatigue free bass. (I will talk more about the fatigue-free aspect in the ADEL Module section). Decay may not be on par with the Dynamic Drivers, but is very good for a BA. Given that there only 2 BA drivers employed for low end, one might get an impression that the IEM is bass light. But the bass drivers on this IEM are, twice the size of the mid/high drivers. So it is really not going to miss out on the bass.
Mids on this IEM is sweet and captivating. The notes are lush without sounding thick nor thin. This adds a bit of a musicality factor. I wouldn’t want to change the mids even a bit, because it sounds just perfect. The same goes for the vocals. The quantity itself is right, but the air that we discussed earlier, makes it seem, like the vocals are a bit laid-back. This IEM may not impress people who are looking for a forward/intimate vocal presentation.
The highs have good extension and texture. It is airy and, has a lot of sparkle. It is a controlled treble, meaning, it does not have any bothering peaks, nor a splashy/tinny/metallic sound (something I am concerned about BA IEMs). I can go on for hours listening to this IEM and feel zero fatigue. But that does not mean this IEM lacks treble quantity. It has plenty of treble to satisfy a regular listener. Just not to the level, to satisfy a treble-head, or someone who prefers a bright tuning.  
The transparency and timbre, is good, but not exactly the most outstanding feature of this IEM, and needs a good source to perform well in this aspect. The vocals and the instruments sound natural. The other aspect of transparency is, the ability to reveal everything in the recording. I feel the A-10 strikes a good balance here, when you are just listening to music and, not critically analyzing the recording. It is forgiving in general, but if there are some big enough flaws, it is going to reveal those. This is one of the reasons, why I feel the A-10 is an excellent Audiophile IEM and not ideal for Monitoring.
A-10 is a very resolving monitor and, it has plenty of details, but it is not necessarily a detail monster. Some IEMs have a bright tuning/thin notes to give an impression, that it has plenty of details and clarity. But 64-Audio did not take that approach here with the A-10. Rather, they made a product that is capable of reproducing all the details with great resolution and clarity and, still sound smooth. Some of the notes that are distant or, low in amplitude or, thin are just mixed in the air. It takes a while to get used to catching these fine details in the air. And, once you start seeing the details in the air, you start to appreciate how this IEM delivers sound, as it helps in the smoothness I mentioned earlier.
A-10 has a very wide sound-stage, but not necessarily the widest. Here, the ADEL module does something interesting. It makes the edge-notes (notes originating from the edges/corners of the stage) sound farther from the center-stage that gives an impression of a wider sound-stage. The height is also good, but the depth is only average. And, if the recording is good, the notes sound so real, that it feels like, the instruments are being played right next to you. The presentation is very airy and laid-back. The air helps giving a sense of openness to the presentation. This also helps in the perception of a natural presentation of the sound.
Okay, I was waiting to get to this part. This is really something to experience on this IEM. They say ‘it’s all about music’. But lately, I seem to forget about the music and, I just sit and observe, how well this IEM + Mojo combo renders the imaging and the instruments. There are some albums, which typically don’t get much of my listening time. These albums are earning new appreciation from a technical stand point. You can literally point your hand in the direction, where the instrument seems to be playing. And to add on top of that, is the separation and layering that seem to be structured like individual notes suspended on strings arranged in layers in a 3-D space.

I do not want to talk about the working mechanism of the ADEL, as I am not technically sound to completely understand how it works, nor how it impacts the sound and our hearing. I just want to talk about, what my experience is with the ADEL module. I ordered my A-10 with the B1 module. B1 has only a single ADEL membrane. 64-Audio claims that the B1, provides better texture in the mids and, adds sparkle to the highs, while reducing the boom from the low registers, in comparison to the S1 Module (S1 has 2 ADEL membranes in the module). I do not have the S1 module, so I am not able to offer a comparison. As for some of the claims of 64-Audio, regarding the immediate benefits of ADEL, here is my opinion and observations, based on my experience:
1. REDUCES PNEUMATIC PRESSURE: This claim seems to be true, as I am not experiencing fatigue from thumping bass on bass heavy tracks. I owned a set of Earsonics Velvets for a brief time. Velvets have a sound tuning knob. With this knob set at lowest bass setting, the bass I heard on the Velvets, seems to be similar in quantity, with what I am hearing on the A-10. But the bass impact on the Velvets, would pound my eardrums and tire me out easily, and was one of the reasons why I returned it. But I have not experienced any such thing with the A-10. 
2. FATIGUE-FREE LISTENING: The above point and the fact that the treble is tuned to sound very pleasant, results in a Fatigue-Free listening experience.
3. LISTEN TO MUSIC AT LOWER VOLUME: I am unable to validate this claim objectively, as there are a lot of variables involved such as; acoustic reflex, mastering volume of albums etc. I increase or decrease the volume based on what I am hearing. My IE80 has a lower impedance and higher sensitivity than the A-10. When playing from Mojo, I listen to the IE80 a few clicks lower than, the volume setting that I use for A-10.
4. 3-D SOUND-STAGE: My answer is Yes and No. Yes, because the sound-stage is very wide and has a good height and a decent depth and the 3-D imaging makes it seem 3-D. No because, the average depth of the sound-stage, holds back the IEM to give the 3-D Holographic Sound-stage.
5. PHASE CORRECTION: Unable to validate this claim. All I can say is, everything seems to sound coherent.

At 18 Ohm Impedance and, 117 dB Sensitivity, A-10 is a very efficient IEM and, does not need an additional amp to be driven sufficiently to loud volumes. It does not have any hiss with my X3ii, but has a very-slight hiss with the iPhone 6 and Mojo, that is only noticeable in a totally silent environment. Chances are, some of you might not even notice the hiss. I am just too sensitive about hiss. As this is a multi-BA IEM, it is advisable to use a source with a Low Output Impedance.
FiiO X3ii & iPHONE 6: Although there are some differences in SQ, between X3ii and iPhone 6, the gap is hardly noticeable, when using the A-10. X3ii can be bright and grainy sometimes, while the iPhone 6 is smooth throughout. These 2 devices have sufficient power to drive the A-10. What I really love about the X3ii, is its clean output. Zero hiss even on High Gain. But the sound quality itself, is not great out of these devices.
CHORD MOJO: My A-10 arrived a couple of days earlier than the Mojo. And for those few days, I was using the A-10 from the X3ii and iPhone 6. I was kind of underwhelmed by the performance. And I was not sure, what improvements Mojo would bring. But I was certainly surprised when I plugged it into the Mojo and hit play (Note: To get the best out of the Mojo, you need to feed bit-perfect). Mojo gives what the A-10 deserves. Not sure if the A-10 benefits from the power output of the Mojo, but it certainly benefits from the DAC section. It brings more clarity, detail, natural tone and timbre. It improves the imaging, instrument separation and layering to an extent that A-10 is taken to a whole new level. If you are planning on getting an A-10 (or its brother A-12), my advice to you is, invest in a good source as well.
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64-AUDIO A-10 (with B1 Module) vs SENNHEISER IE80 (with Tape-Mod): A-10 sounds like an elder and mature brother of the IE80. Both have many similarities in the sound characteristics, such as: airy and laid-back presentation, lush notes and smooth sound. The bass and treble quantities are similar, but the A-10 has better quality. A-10 has better texture and, less boom in the bass. It has finer nuances in the treble. The bass is also tight and clean on the A-10 that it does not bleed into the mids. IE80’s biggest weakness is, the loose bass with the mid-bass bump that bleeds into the, already recessed mids. The mids on the A-10 are certainly clearer, forward and textured compared to muddy mids of the IE80.
The transparency and timbre is also a clear step-up over the IE80. Although IE80 has a wide sound-stage, A-10’s sound-stage is wider. A-10 also wins in terms of the sound-stage depth. IE80 sounds a bit flat in comparison. Resolution, Detail Retrieval, Clarity, Imaging, Instrument Separation and Layering are aspects in which the A-10 is many steps ahead of the IE80. I have always considered IE80 to be a technically capable IEM. But A-10 is on another level. If there is one area where IE80 has an advantage, it is the decay. It feels very fluid and effortless. So yes, A-10 is a clear upgrade over the IE80 (provided you match it with a good source).

- You are looking for high performance high-end IEM, with a balanced tuning, yet fun sounding, without an analytical character
- You prefer a smooth, relaxing and laid-back sound
- You prefer texture and layers in the bass rather than slam and authority
- You are looking for IEM that excels in technical capabilities especially the imaging, instrument separation and layering
- You want a fatigue-free sound
- You are looking for a perfectly neutral monitor with analytical character
- You want a very resolving IEM that exposes all the details/flaws in the recording
- You prefer an energetic sound and, most of your music are fast-paced
- You are looking for something with a bright tuning or great treble quantity
- You prefer slamming and authoritative bass
- You want an IEM with a upfront overall/vocal presentation 

64-Audio markets A-10, as a neutral reference monitor and seems to be overlooked for the very same reason. But, I see it, as an amazing audiophile IEM. It has a balanced sound, without a bright tuning or thin notes, yet has incredible detail and resolution that is not fatiguing to listen to, even for hours. The sound is lush and smooth and retains good texture. ADEL module adds some benefits over the already excellent sounding IEM. What sets this IEM really apart, is the technical capabilities. Especially the sound-stage, imaging, instrument separation and layering. If you want to do justice to this IEM, do invest in a good source (I can’t stress this point enough) and you will be rewarded greatly. I set out on getting an End-Game-For-Now setup. And that is exactly, what I have got with the 64-Audio A-10 and the Chord Mojo.

@kaye23 for bringing 64 Audio ADEL IEMs to my attention
- @Canyon Runner (Steve), who announced the 'Audio Enthisiast Program' here on Head-Fi that aided the purchase and answered some of my questions on the ADEL IEMs thread
- Isabel at 64-Audio for helping me with the Demo Program and also the order process
- Other members on the ADEL IEMs thread, who helped me, by answering questions and, encouraging me to purchase a good source that has led to, me enjoying the A-10 immensely

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@cyph3r , yea, its a thing of beauty. The reason why I opted for translucent shells and no artwork.. :)
When you stated it took a week to get used to the tight fit, were you experiencing pain while growing accustom to the fit?  In your opinion, are CIEMs more comfortable than 64 Audio UIEMs or did you not get a chance to try the UIEM?
Max, it is the whole new experience of having something full stuffed in your ears. In your regular UIEMs, it is usually a soft material like Silicone or Foam pressing against a part of your ear. In case of CIEMs, it is hard acrylic material. Something like wearing a loose ring and a perfect fitting ring. The loose ring sure does feel nice instantly as it is not pressing against your skin, but keeps slipping off. But the perfect fitting ring seems too tight initially, but over time, your finger gives way to the tight fit and, it stops bothering you and, ultimately it gets comfortable. 
I was experiencing discomfort and pain in my right ear for a week.  For my right IEM to sit comfortably, it has to be in this one position. Even a slight deviation from that position can lead to discomfort. I probably am going to send my right shell for a refit to take advantage of the 30-day free refit. I have not experienced any such thing in my left ear though. It has always been comfortable. Except for the first few days of break-in. The seal is also so good on these, that the seal does not break even when I am chewing food.
Yes I did try the UIEM version U10 before I ordered my A10. During that first week, I did wonder if I had made a mistake. But not anymore. Once you get used to the Custom fit, it feels strange to go back to the universal fit. When I am wearing my IE80 these days, it feels strange. Like it is about to slip out anytime.
But the custom IEMs do have a couple of disadvantages. These are the 2, I have experienced so far:
1) When I start my day in the office and I am inserting it for the first time for the day, it feels a bit tighter and the inserting is not the smoothest experience. But a few minutes later, when you try to insert or remove, it feels like your ears have changed its shape exactly to the shape of the IEM.
2) Sometimes when I don't get enough sleep, I cant get a comfortable fit the next day. It will be about afternoon before I can start experiencing a comfortable fit again.
So, in short, if I have to do it again, I'd still go for the Custom.