64 Audio - Official Thread

The Nio IMHO is the best looking of the whole 64 Audio Universal lineup. I would love my U18t’s to look like them. Beautiful iems.


As soon as I get my Hero’s I will be able to do a side-by-side comparison. So far though Nio has been simply awesome and I am able to listen to them all day without any fatigue. Great for all genres I throw at it.


Hero is in the house! Now it’s time to dig in so see how these two compare.


Hi everyone, I have the cobalt and use it with my 64audio U12t and Nio. Every time I raise the volume past 75% on my iPhone, the Cobalt crashes. Any ideas? I read that it could be an impedance issue with these IEMs, but I have seen many people use the 64audio line with Cobalt online.

Btw, tried different phones, adapters, and cobalts. Same behavior.

Appreciate any advice. Thank you!

Nice revew @Precogvision

I need to try me a nio.


@antdroid Thanks! I forgot to make a post haha. If anyone wants to read my review of the Nio, it’s been published here.


Really enjoyed your review. I’m loving my Nio every day.

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waiting for delivery of my nios, hopefully by Monday. While I’m not a true basshead I do want a full extended and controlled bottom end. I’m hoping either the M20 or MX gives me that.
Will give my impressions once I have them

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You might prefer the MX module then. I love the M15, but it is bass heavy. Very impactful, whereas the MX attenuates that to a more “normal” level.

And now I’ve gone further down the rabbit hole and am adding the U12t to complement the Nio. Lord help me…

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Thanks for the reply, I also have Fir’s version of apex modules so I have a lot to play with.

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I am deciding between this and the Campfire Solaris 2020. Any suggestions?


Depends on what type of sound signature you enjoy. What genres do you like and what do you like about them?

Resolves NIO review check it out here!


As usual an excellent and thoughtful review. The comparisons that Andrew gives really allow one to understand the strengths and weaknesses. @Resolve is my trusted reviewer.


Been into Classical, Ambient, Jazz, and Progressive rock lately. But I’ve been listening to all types… except gospel and country.

Hmm. Okay. So I could see the Solaris and the Nio (with the MX module) being pretty close in sound. The Solaris was probably a little more holographic in its signature due to slightly more recessed vocals, but in a decent way. I didn’t find either set to be treble sharp or sibilant. The Solaris just didn’t have enough bass oomph for me. One of the benefits the Nio has is that it’s modular. You can get a leaner sound with the MX and then a bassier sound with the M15 and M20 modules. So if you want some real low end punch at various points in your listening then the Nio can do that. I personally enjoyed the Nio better than the Solaris, but it was relatively close. I also find that the Apex modules work great in letting some of the sound pressure out too. They both had similar in-ear comfort for me.


Interesting, thanks for the insight! Didn’t know there was module capabilities for the Nio!

In this review, I will be discussing the latest in-ear monitor (IEM) from 64 Audio. The Nio is priced at $1699, which makes it the lowest-priced model in their universal audiophile series of IEMs. This model is not offered as a custom at this point in time, though it does have some semblance to the custom N8 model.

The Nio is a hybrid model, featuring a dynamic driver for the lows, 6 mid-range balanced armatures, 1 mid-treble balanced armature, and a single tia driver for the treble. Like other models, the Tia driver is essentially an open-back BA driver, and the Nio also features the Linear Impedance Design (LID) and APEX modules for releasing pressure through the outer shell of the IEM.

The APEX modules are not only for pressure relief; they can also be switched with the two additional included sets to tune the sound profile quite a bit, and I’ll discuss those differences in this review.

The Nio takes on a similar shell design to others in their current lineup with the tear drop shape which some people may find comfortable and some may not. I personally find it very comfortable given the right set of tips and cable, which I’ll discuss a little later.

The faceplate replaces the boring plain look of previous models, which remind me of just a sticker placed on the aluminum shell (see U12t), with a very attractive blue-green highlighted abalone in-lay that sparkles and glistens in lighting and different viewing angles. The chrome-colored shelled finish, along with the abalone centerpiece, make this Nio a stand-out set in terms of beauty and eloquence in the 64 lineup.

One other thing to note is that the case that is included with the Nio is a updated case that is round and much more attractive than the previous hard plastic box that came with previous models. This provides are more appealing look to carry around which is a nice addition to one of the minor complaints I had with other 64 models. The cable is pretty much the same as usual, which means, I highly recommend spending cash on a replacement cable immediately. The default cable it comes with isn’t the most easy to handle and the pre-hook design makes it hard to keep a good seal in my ear. This is definitely my own personal experience, but I have heard similar issues from many other users as well.

Before I get into the sound impressions, I do want to thank Headphones.com for sending this unit on loan to me for review!

Sound Impressions

The Nio is a bass-focused, but also a balanced IEM with a nice warm signature that is FUN. If you’ve read my reviews in the past, or have spoken to me in-person or online, you’ll know or get the impression that I am much more of a neutral-target preference type person, but the recent releases of the Mest, and the Nio have made me question whether I am just a closet basshead or not. So, at this point I just gave away my impressions of this IEM – I like it. I like it a lot!

Taking a step back, I reviewed the U12t, also from 64 Audio, several months ago, and gave it significant praise. It’s still in the top of my recommendation list for a top tier IEM, but I’ve always been looking for a nice hybrid set. Well, the Nio is pretty darn good and similar enough to the U12t tuning.

It is heavier on the bass end with the dynamic driver pounding away at your ears and giving a fun, but also natural decay and slam and providing some of that fun impact that you can’t always fully replicate with balanced armatures in the U12t despite how well it does it. Texturing capability in the low end is really nice, though it’s not necessarily as resolving down low as a balanced armature is, and the amount of bass the M15 module provides can be a little over-done at times and can cause a very small of smearing.

The Nio presents the midrange with a warm and lush sound, but not too thick that I’d consider it gooey overly intoxicating. There’s not a sense of richness to it that overemphasizes anything in the midrange. That’s because I feel like the midrange is generally flat but with a bass shelf that starts in the lower midrange, and the upper midrange is inline with a proper pinna rise that balances male and female vocals well. It’s coherent, but still suffers in with some slight disjointedness between the low end dynamic driver and the midrange-balance armatures. This is a bit more apparent due to the significant micro-dynamic slam and punchiness that the Nio low-end generates, especially if you get a great seal.

The treble is a bit on the laid-back and soothing side. It’s generally relaxed and tame, but extends well enough. I’d put it in-line with how I felt with the U12t. It’s perhaps a little too recessed for my preferences, but only slightly. Instruments are well defined though, and I never get the sense that there’s major timbre issues or any thing totally lacking adequate upper harmonics, and that’s a good sign. Many hybrids I’ve tried fail due to either coherency issues or too much coloration in my opinion.

Imaging is actually very good on this set. I liked the amount of instrument separation on the M15 default module and it’s soundstage was a little wider than I actually expected, and is about on par with what I remember the U12t having. Orchestral pieces with a lot of instruments are well defined and picked out easily. The amount of bass can make some complex rock and electronic passages a little challenging, but not to the point where I will make a complaint about, except when using the M20 module, which I’ll talk about now.


I’m going to take a quick break to start talking about the modules. The Nio comes with three sets of the Apex modules that 64 Audio uses on all their audiophile IEMs. With the Nio, 64 Audio introduces the MX module, which is the least isolating with a -10dB noise isolation rating as opposed to the -15dB and -20dB of the M15 and M20 modules that have been standard included accessories with the universal lineup.

Each of the 3 modules included have some sort of effect on tuning.

The M15 is the default module pre-installed on the Nio out of the box. It’s my preferred sound signature of the modules and I’ll cover the differences of the others before going into more general sound observations

The M20 adds a touch more bass and less treble over the M15, and I quickly found that even though the measurements are very near similar to each other, that the M20 sounded more compressed in both dynamics and soundstage. The bass has a slight bigger impact and slam, but makes it rather muddy as well. I just found the M15 was already bordering on too much at times, and that M20 brings it over the line for me.

The new MX module is an interesting one. It somehow completely removes the bass and leaves the Nio to have a little bit more of a neutral tuning with a small bass bump, but with rolled-off sub-bass frequencies. Normally, I do like a more neutral tuning, but in the case of the Nio, I felt that going with the MX module removed the fun factor of the M15 while not having any subbass rumble in the MX. In this case, I find the MX a bit too lacking in enough good qualities despite a cleaner sound signature.

Further Sound Impressions

The Nio keeps surprising me on every listen. Yes, it’s not something I typically would enjoy – bass is plentiful, treble is relaxed, and upper mid-range is a tad hazy, but there is a nice refreshing alternative to my normal listening gear and the fact that the minor colorations are not distracting, and in fact, quite pleasurable make this a great IEM for a lot of music.

In The War on Drugs song, “Eyes to the Wind,” from their Lost in the Dream record, I find the Nio pushes Adam Granduciel’s lead vocals forward with a distinct and clean sound. Maybe it’s a tad too edgy sounding, and lacks a little breathiness, but it sounds clearly defined from the background smattering of buzzing guitars, keyboard synths, and a drum and bass line that continue to pound and provide a careful and intricate amount of layering and a body of sound that is well textured and scattered across a sea of noise. The wall of sound is harmonious and has power and a very natural amount of resonance and decay on the Nio, making this type of music a stand out pairing for me.

The famous intro to “Such Great Heights” by the Postal Service is an alternating panning of simple tones scattered across with an average amount of width on the Nio. The build-up continues with a heavy bass synth that ends up carrying the entire song. On the Nio, this bass line has a a small rumble that continues throughout the song. It isn’t the most defined I’ve heard it, but it does have a feel to it that is a nice alternative. Ben Gibbard’s voice throughout the track is soft-spoken, but still brought forward and is carried fairly naturally with the Nio. If anything, it might be a tad too forward.

In the classic, “People are People” from Depeche Mode, the Nio flat out blasts your skull from left to right with the heavy drum beats smashing on both channels. A lot of these Depeche Mode and New Wave tracks have a heavy palate of electronic and real drums that I feel need a well-tuned dynamic driver to carry the weight correctly. The Nio is a nice balance here since Alan Wilder’s drums take advantage of the dynamic driver, while the rest of the heavily synthesized tracks from the famous band are handled the BAs. Dave Gahan and Martin Gore’s distinguishing vocals sound fine in this track, though Gahan does lack a little bit of the powerful gusto that I am sometimes used to.


I could probably go on and on with different music and how they perform on the Nio, but overall I am left with a lot of smiles listening to this IEM, which I wasn’t totally sure I’d like or not. I’ve been hunting for a hybrid IEM that can do the low end well, while retaining the resolving nature of balanced armatures, and it’s been a challenge to find IEMs that do all of this while still retaining good coherency and tuned well.

The past several months have seen the release of the Unique Melody MEST, the Campfire Solaris 2020, the Thieaudio Monarch and Clairvoyance, and this 64 Audio Nio. All of these are excellent performers, and it’s a tough decision to recommend which one, as they are all good in their own way. The Nio is probably a generally safe bet for most music listeners, though it does stray a little heavy on the low end, so perhaps those who like less bass may not need apply. That said, as someone who tends to stay more neutral in bass quantity, I enjoy these a lot, so there’s that.


64 Audio Flagship Shootout - Nio, U12t, Tia Trio, U18t, Tia Fourte

I couldn’t fit the U18t, so cut me a break!

I. Introduction

64 Audio’s roots are a humble one; after all, every company has to start somewhere. But what started as one man, Vitaliy Belonozhko, tinkering from the confines of his home has expanded into a full-fledged family business based out of Vancouver, WA. Needless to say it hasn’t been an easy journey. From strained business relationships to fractured family lines, 64 Audio has faced no shortage of adversary. But if there’s one thing for certain? It’s that 64 Audio has risen to the challenge time and time again to establish themselves as one of the industry’s foremost players; they are purveyors to some of the finest IEMs in the world.

Of course, as a relative newcomer to the hobby, I was not privy to 64 Audio’s rise to prominence. Nonetheless, I still recall browsing their site as a starry-eyed newbie to the hobby and being blown away by - if nothing else - the sheer cost of their IEMs. Countless hours were spent browsing their website and fantasizing what it would be like to hear one of their IEMs. Well, stuff happened (more closely, I jumped off into the deep end of the hobby), and a year or so later, I’ve had the unprecedented opportunity to hear their entire flagship line-up. Funny how things turn out like that, but I digress.

64 Audio’s lineup is pretty cool (and can be difficult to navigate) because they have no less than five flagship-worthy IEMs. In this shootout, I’ll be looking at the following IEMs:

I will cover each IEM’s respective tonal balance and give an in-depth breakdown of their relative technical performance. Do feel free to skip to near the end where I’ll neatly summarize my thoughts for convenience. So without further ado, let’s find out which 64 Audio IEM is for you.

II. Source & Drivability

All critical listening was done off of an iBasso DX160, A&K SP1000M, and iFi Micro iDSD Black Label with lossless FLAC files. I generally opted to use my own cables and tips (silicon SpinFit CP145). All of these IEMs are fairly easy to drive and you should have no trouble running them off of a mobile device. Hissing was a non-issue.

III. The Tangibles

All of the 64 Audio IEMs except the Nio arrive in large, black cardboard packaging. For such large packaging, the included accessories tend to be more milquetoast. Depending on the IEM you’ve purchased, you’ll generally receive an assortment of the following:

  • 64 Audio Premium Leather Case
  • TrueFidelity Eartips (S,M,L)
  • Silicone Eartips (S,M,L)
  • 48” Premium Cable
  • Apex Modules (for the U12t, U18t, and Nio)
  • Sticker

Admittedly, I’m not a big fan of the premium leather case. It’s usable, but I would like to have seen a higher-grade of leather being used, especially for such expensive IEMs. Or even better, to have seen it replaced altogether with one of the brand’s aluminum hockey puck cases! That aside, something I’m not a fan of at all is the stock cable. It almost feels like…paper mache? Worse yet, the memory wire exacerbates the strain on the IEM’s connector joints each time you adjust the cable. No thanks, I would plan to pick up an upgrade cable.

The 64 Audio IEMs make use of a teardrop housing constructed of aluminum. The faceplates tend to be more understated; this is personal preference, but I do prefer this type of look. But I’m not too picky. On the other end of the stick, the Nio eschews this trend with an abalone blue faceplate; I’m a big fan of this aesthetic. For fit and comfort, the ergonomics of the 64 Audio IEMs work wonderfully for my ears, and I can listen to them longer than any other IEMs that I’ve worn. Of course, part of this has to do with 64 Audio’s unique technologies which I’ll be exploring more closely below.

IV. Technology

64 Audio utilizes several patented, unique technologies in their IEMs. Here’s a breakdown for your convenience:

Apex - When you listen to IEMs for prolonged periods of time, sound waves in a sealed canal build up and lead to discomfort; Apex serves to slowly release some of this pressure, thus extending listening time. The way this is achieved is simple but clever. A vent is present to equalize pressure; viscoelastic open-cell foam is placed in the vent to both retain the low-end frequencies and control the release of air. Within the context of the various Apex modules - modules you can swap between certain 64 Audio IEMs - vents are simply added to the module. The M20 has a single vent, the M15 has two vents, and the MX likely has three vents. The trade-off is a minor loss of isolation in that order. This technology works. I can wear the 64 Audio IEMs significantly longer than other IEMs with minimal fatigue.

As for what these modules do sound-wise, they predominantly affect the bass regions. The MX module, aside from sloping off the sub-bass, also results in a bump at 4-5kHz on measurements for reasons unbeknownst to me. On a psychoacoustic-level, the changes are more widespread. When there is less bass, one’s perception of the midrange and treble is brought forward. As a result, staging has a tendency to expand, and layering - the perceived space between instruments - is more pronounced.

LID - Linear Impedance Design. Different audio sources pack different impedances, and the way these impedances react with the various drivers in an IEM can alter the frequency response. This is part of the reason why you’ll notice that IEMs sound different between sources. As I understand it, LID essentially consists of L-pads to flatten the impedance curve, thus maintaining consistent frequency response between sources. This way you’ll always be getting the intended sound signature of your IEM. The U18T and the Tia Fourte do not have this technology.

Tia - The tia driver is 64 Audio’s proprietary, unlidded balanced armature. Whereas most balanced armatures pass sound through a tube, the tia driver is mounted directly to the spout of 64 Audio’s IEMs. By bypassing ancillary frequencies and firing directly into the ear, this should theoretically translate to reduced resonance and cleaner, more extended highs. In practice, I hear all the 64 Audio IEMs as exhibiting strong peaks for air anywhere from 15-17kHz. This phenomenon adds to exceptional microdetail up top, and I suspect it plays a strong role in the unique staging that the 64 Audio IEMs exhibit. Depending on the extent of one’s hearing, some listeners might find these peaks more difficult to hear but can still benefit from the unique texture present to the tia sound.

V. Sound Analysis

Not sure how to read graphs? A frequency response graph depicts relative SPL (sound pressure level, or how loud the IEM is) at each part of the audible frequency range. In this case, at least for humans, that’s from about 20hZ to 20kHz. These measurements were taken off of an IEC-711 coupler and there is a resonance peak at around 8kHz. The coupler is only certified up until around 10kHz and, because of this resonance peak, measurements after this point should not be considered entirely accurate.

In general, I would say that most of the 64 Audio IEMs I’ve heard are well-tuned; you can tell careful thought went into each tuning. That said, 64 Audio doesn’t seem to have a distinct target in mind which makes it incredibly interesting to see the direction they decide to take. It’s one thing to consistently tune good IEMs when you have a set target; it’s even more impressive to consistently tune good IEMs to a variety of flavors.

Because of the flexibility afforded by the Apex modules, tonal analysis will assume use of the M15 module unless specified otherwise.

64 Audio U12t - The U12t follows what would be close to my ideal target curve; a more laid back, slightly warm presentation that can be listened to for hours on end. It is sub-bass oriented with a near-dead balanced midrange that favors male vocals by a hair. I adore the upper-midrange recession from 2-5kHz which keeps away pesky edginess and sibilance. Treble exhibits sufficient amounts of stick impact with a peak at 5khz, followed by a dip after 8kHz, and then a sharp rise at 15-17kHz. Depending on the extent of one’s hearing, the U12T can sound anywhere from darker to tizzy. In my case, what I hear with the M20 module is a more laidback treble response but with excellent extension and a pleasant zing up top.

64 Audio Nio - The Nio has a similar tonal balance to the U12t but stacks on a good deal more bass with the M15/M20 modules. Aside from warming up the sound significantly, this has two major consequences: It pushes the Nio to the point of mid-bass bloat, and the midrange skews a good deal thicker. The Nio also appears to peak higher than the U12t in the treble; generally, it’s a tad too dark for my tastes with these modules as much as I enjoy the extra bass and the smoother signature. The MX module shakes things up quite a bit. The Nio takes on a much more balanced, lean sound. You lose the awesome sub-bass, but staging and layering improve significantly.

64 Audio Tia Fourte - The Fourte follows what I can only describe as 64 Audio’s interpretation of an audiophile tuning. And well, this interpretation is interesting to say the least. The Fourte is unabashedly colored at the expense of tonal accuracy. Bass, like most of the 64 Audio IEMs, follows a perfect sub-bass emphasis. The midrange, however, exhibits two dips, one from 600hZ to 1000hZ and another from 3-4kHz, lending to some uncanny valley and nasalness. Treble is strongly emphasized throughout the crash and extension regions; this is a brighter IEM. I can’t say I’m a fan of how the Fourte has been tuned, although there is certainly merit to some of the decisions made here that I’ll elaborate on below.

64 Audio Tia Trio - The Tia Trio is the Fourte’s younger brother that, ironically, has a more mature tuning if you’re asking this reviewer. The dip from 3-4kHz present on the Fourte is eschewed, bringing back the upper-midrange. Gone is the honky nasalness. Treble exhibits something of a lower-treble suckout followed by a good deal of energy in the mid-treble and extension regions; fizzly is how I’ve heard it best described. While the Tia Trio doesn’t follow any sort of academic target curve, it’s unmistakably a well-tuned, fun IEM where everything somehow just clicks together.

64 Audio U18t - The tonal balance of the U18t is something of a mild-V shape to my ears. You have a lot of mid-bass, enough to rival the Nio. The upper-midrange, however, is more forward and there’s good amounts of lower-to-mid treble presence. Note-weight skews ever-so-slightly thicker to my ears thanks to the sheer presence below 1kHz. On the whole, the U18T has a brighter, more forward presentation. The U18t is well tuned, there’s no doubt, yet I do find the tuning to be the most unremarkable of the 64 Audio IEMs. There’s a lack of “character” to its tonality that I can’t quite put my finger on. And honestly, I probably would not consider this a reference IEM despite the claims to the contrary.

Tonal Balance
Tia Trio
Tia Fourte

VI. Technical Performance

Ah yes, here’s where things get real fun. Make no mistake that these are mostly very well-tuned IEMs. Still, you can have the most well-tuned IEM in the world, but it doesn’t mean much if you can’t imbue your IEM with the fickle, ever-elusive intangibles. This is a reference to characteristics of sound outside of measurable frequency response, or characteristics that we don’t know how to interpret from existing measurements yet. Thankfully, all the 64 Audio IEMs that I’ve heard have the intangibles in spades.

Detail Retrieval

I might’ve noted this before, but technical jumps between IEMs are not actually as big as you might think; or at least, this has been my experience thus far. This holds especially true once you start hitting around the kilobuck price point and are comparing between highly-technical IEMs.

That in mind, I would rank the 64 Audio IEMs in the following order for detail retrieval:

Detail Retrieval
Tia Trio

Some might find my rankings here surprising, so I’ll do my best to explain why I have them ordered as such. First, there is a common misconception that the more BA (balanced-armature) drivers that you can cram into an IEM, the more detailed it will sound. A BA driver is a miniature speaker. If you have more BAs to dedicate to each part of the frequency spectrum, that should - in theory - translate to greater detail, right? But it’s not that simple, and ultimately, implementation reigns supreme.

Case in point, the Fourte makes use of only three of the tia drivers for the midrange and treble frequencies. But for a sense of micro-texture and “wetness,” this is where the Fourte shines most. The upwards skewed treble of the Fourte also inherently boosts the perception of detail. Similarly, the Tia Trio only has two BA drivers tokening these frequencies, but has terrific resolution thanks to its upper-midrange tilt and treble. These IEMs can both comfortably play near the top for detail.

You see that tuning can also play a massive role in the perception of detail. Generally, skewing tonal balance toward the low-end impedes clarity and vice versa. The Nio is a prime example of this. With the M15/M20 modules, the midrange leans towards the thicker side. As a result, notes tend to come off as fuzzier and less defined. But plug in the MX module which brings down the bass, and note-weight hits near dead-neutral and resolution improves significantly. I would put Nio’s overall detail at the top end of the kilobuck bracket.

The U12t and the U18t are also something of a dichotomy. Despite sporting six more BA drivers than the U12t and having the advantage of a brighter sound signature, the U18t sounds less detailed to my ears. I can only surmise that the drivers being used in the U18t are distinct from those in the U12t; this reflects most in their respective transient behavior which I’ll delve into more closely later.


To lend some context to how I qualify imaging, it is most closely a reference to the degree of which an IEM is able to shape the “walls” of the stage around the listener. Soundstage, then, is a derivative of imaging, as are positional cues (an IEM’s ability to localize instruments on the stage). The 64 Audio IEMs are an interesting study. They all have above-average imaging to my ears. When you consider that the vast majority of IEMs are “three-blob” in my book, that’s quite the feat. Now, please understand that much of what I will talk about next is anecdotal and largely theoretical.

I would posit that imaging is strongly influenced by treble presence in the “air” regions (so 10kHz onwards). Recall my earlier explanation of the tia driver; all of the 64 Audio IEMs have excellent treble air thanks to these special tweeters. Treble air can lend to the perception of instruments floating on the soundstage to my ears. By extension, this plays into soundstage height and qualifies the IEMs that I would consider to be holographic. While this buzzword does not apply to all of the 64 Audio IEMs, all of these IEMs’ upper-harmonic tia peaks at least lend to the perception of wider, more spacious staging.

Fourte & Trio - The Fourte and the Trio take this one step further by making use of recessions in frequency response from 600hZ to 1kHz. In the case of the Fourte, it has an additional recession from 3-4kHz. I alluded to this earlier, but there is rationale for tuning like this. Dipping frequency response often has the effect of imparting a sense of spaciousness; the Fourte and Trio sound noticeably larger in soundstage size than their peers. Needless to say I would qualify these IEMs as holographic. But this comes with imaging quirks too. The Fourte, in particular, appears to have a disconnect with which the center image is “pocketed” and doesn’t ring quite as sonic-wall free as the rest of the stage. The Trio mitigates this effect and suffers more on the front of positional accuracy. Unfortunately, I have to dock points here, despite these IEMs having terrific stage size and “wow” factor.

U12t - A large part of the reason why I own a U12t has to do with its center image distinction. A brief explanation is probably in order: When one has two speakers set up side-to-side, there should be the psychoacoustic allusion of a third speaker in the center; this is most closely soundstage depth when talking about IEMs. Most IEMs do not have much depth and have an effect where vocalists sound like they are behind the eyes, or worse, coming directly from inside the head. But thanks to its 3-4kHz recession, the U12t has the deepest stage that I have heard in an IEM. Vocalists and instruments which token the center image truly sound - not just feel - like they are in front of you. To top it off, the U12t has the best positional cues of its brethren.

Nio & U18t - The Nio has the most intimate stage of the 64 Audio IEMs, particularly with the M15/M20 modules. But the MX module opens up the stage significantly, to the extent of which I would put width on par with the U12t albeit minus the same level of soundstage depth. Likewise, the U18t has fairly open staging. The center image on the U18t is wider than both the Nio and the U12t’s with more of the aforementioned “feel” characteristic.

Tia Trio


For context, dynamics are largely a reference to the intangibles of transient attack, or what some might call the leading edge of a note. All of the 64 Audio IEMs that I have heard have a certain “smoothness” to the way transient attack is articulated; they seem to skew somewhere towards the middle in terms of speed. This is distinct from most BAs which are known for their rapid-fire attack.

I suspect that this quality has something to do with both the Fourte and U12t’s impressive dynamic range. For macrodynamics, the way an IEM scales quiet-to-loud gradations, these IEMs take top marks: They excel at articulating the weight, intensity, and contrast behind dynamic swings. You’re going to feel the energy building up in a track, when a drop is about to slam you, and when the cadence of a track sinks. This is really a breath of fresh air compared to the upwards-compressed quality that a lot of BA IEMs exhibit to my ears.

Along these lines, the Trio and U18t suffer from this quality more closely. The Trio’s dynamic compression isn’t bad at all, but the U18t, in particular, sounds really flat. On everything I put through the U18t, I couldn’t find myself nodding along or getting engaged with the music. Perhaps this skews back to why I called its tonal balance unremarkable, but it is - to my ears at least - the least engaging of the 64 Audio IEMs. I would say the Nio falls somewhere between the Trio and U12t for macrodynamics.

For microdynamics - that is decibel gradations on a more intimate scale like vocal inflections - I would not say that any of the 64 Audio IEMs exhibit this quality very closely. This is not a knock, as most all IEMs I have heard do not have good microdynamics, at least to my ears. In fact, I would say that stuff like the Fourte and the U12t are on the better end of the stick for this metric compared to most of their competitors.

Tia Trio

Now, dynamics can also refer to the intangibles of bass. You know I’m a fat bass-head, so another shootout is warranted here.

In my brief stint of this hobby, I’ve come to note that different subwoofers have varying degrees of individual tactility, character, to them devoid of frequency response. The subwoofer used in the Tia Trio is distinctive of the IEM world’s crème de la crème. There is a certain richness to it that simply drips authority and refinement; I love the way it slams. You still have the ever-so-slight softness to transient attack that characterizes all the 64 Audio IEMs, but I would not hesitate to put the Trio’s bass alongside something like the venerable Sony IER-Z1R; it’s that good.

It might come as surprising, then, that the Fourte’s bass isn’t so great. I mean, it’s good in isolation - you know, if we were talking about the sub-$500 bracket - but it’s not really class leading. There’s a certain poofiness to the way it slams, and transient attack is a good deal more blunted than the Trio. I’ve had a couple of friends demo the Fourte who thought they were hearing BA bass. Yeah, that’s not a great sign.

Like so, when one is talking about BAs tokening the bass frequencies, there’s a pretty common stigma: BAs just don’t do bass. Or at least, they don’t do it well. They don’t slam, they don’t decay adequately, and they have pretty horrible timbre. But the U12t would like to have a word. It is my benchmark for BA bass with more slam and texture than most dynamic drivers I’ve heard; simultaneously, maintaining the typical nuance of a BA driver with some added softness. While the U12t’s not going to match top-tier threats like the Sony IER-Z1R or the Tia Trio for bass, I’d say it’s enough to satisfy me 90% of the time. And this is coming from a fat bass nut.

Then the Nio’s basically what you’d get if you swapped out the U12t’s BA drivers for a dynamic driver and turned it up to 11. Texture, rumble, and slam are terrific with the M15/M20 modules. Call me a bass glutton, but I don’t really like Nio’s bass all that much with the MX module. Nio’s foremost a sub-bass specialist, then, and the trade-off is that the mid-bass takes on a more smeared, bloated quality.

Speaking of mid-bass, the U18t has a lot of it, and it doesn’t translate as nicely with the U18t’s BA drivers. The overt mid-bass emphasis can certainly lend to the perception of slam, but for a sense of true physicality, well, I just don’t hear it there. Like so, the U18t’s bass is more characteristic of your typical BA IEM with a certain fartyness to it. The U18T’s still doing better than most BA IEMs, but I’d be remiss if I didn’t point out that its younger brother, the U12t, undercuts it and performs noticeably better for bass.

Slap Factor

Timbre & Coherency

When one is talking about IEMs, timbre is most closely a reference to the pattern of decay. This is especially relevant when IEMs make use of BA drivers. BA drivers decay much quicker than their dynamic driver counterparts, leading to egregious transient overlap. The sort of metallic strain and note weightlessness that ensues is often dubbed “BA timbre”.

At this point, it might come as no surprise that 64 Audio has worked some magic with their IEMs yet again. All of the 64 Audio IEMs are largely devoid of BA timbre, or have less than one might expect if they’ve heard a BA IEM before. I would say that the hybrids - namely the Nio, Trio, and Fourte - tend to exhibit less of this quality simply by virtue of having a dynamic driver for the low-end frequencies.

But it’s not all sunshine and daisies. Hybrids are popular because they can combine the best of both worlds between a dynamic driver (generally for bass) and a balanced armature (midrange and up). However, coherency becomes an issue for hybrids, as drivers are being matched with distinct transient behavior. To this end, IEMs like the Tia Trio and Fourte are noticeably more disjoint than their peers. For me, this is most obvious when taking a look at the resolution and speed of their bass; the BAs tokening the midrange and treble tend to skew quicker and more resolving. This perception of disjointedness isn’t helped by these two IEMs’ tunings either.

To make a long story short? Trade-offs. The 64 Audio hybrids might have more pleasant timbre and better bass production, but by virtue of design, they’re simply not going to be as coherent as IEMs like the U12t and U18t. Still, I think it’s worth considering that the majority of listeners will probably never notice this stuff. And if you don’t, then I say all the more power to you! The way I see it, it’s just one less thing to worry about, right?

I’ll refrain from ranking these traits due to the discrepancy at hand and their highly subjective nature.

VII. The Subjective

Speaking of subjectivity…yeah, I don’t think there’s been much in this shootout. But to be clear, no review will ever be objective anyways; “objective reviewing” is an oxymoron and all that. So let’s get down to the nitty-gritty. Which ones would I actually recommend?

In case you can’t tell, I’m not a big fan of either the Tia Fourte or the U18t. The Tia Fourte’s simply too far lost in the pursuit of flavor at the expense of tonal balance; that’s a shame because it’s one of the most technical and unique IEMs on the market today. As for the U18t, sure, it’s pretty solid all-round, but I just don’t hear that special sauce. And we haven’t even considered the hefty price of entry for these IEMs (let’s not go there).

So that leaves the other three IEMs: the Nio, the U12t and the Tia Trio. Admittedly, I have a real soft spot for the Nio. It’s not the cleanest, most technical IEM for the price, but the tonal balance is phenomenal. I love how it leans wholeheartedly into that warm, gooey sound, but that at the swap of a module, you essentially have a new IEM with a much cleaner tonality. It’s really just such a flexible IEM; a terrific entry point to the 64 Audio sound. Of course, it’s still by no means cheap, but I do think it can comfortably hold its own against the competition.

The Tia Trio is also pretty sweet. Sweet enough, in fact, that I contemplated purchasing my own at one point. It’s one of those IEMs that doesn’t have any right to sound as good as it does. No, really. It graphs all sorts of wonky, it’s only sporting three drivers, and it’s going to cost you an arm and leg to purchase one. But again, it just works. There’s a certain smoothness to its presentation that defies its aforementioned lack of coherency, and I’ve heard few IEMs so good for the likes of EDM. This is unmistakably a top-tier IEM.

And then there was the U12t. “Here he goes again,” some readers are no doubt thinking. I’ve made it no secret that this is my favorite IEM. The U12t’s a prime example of when the whole is greater than the sum of its parts; when a company’s product challenges their own antecedent products on the playing field. No, it’s not perfect. But audio is characterized by a series of compromises, and the U12t is the IEM that makes the least mistakes to my ears. This is one of the world’s best IEMs; slap the U12t on your shortlist.

VIII. The Verdict

I know this was quite the write-up. In fact, I want to say it’s the longest I’ve ever done for a review! So if your mind is melting (hey, I don’t blame you), here’s the Twitter-review summary for each of these IEMs:

  • The Nio is the IEM you should consider if you’re on a “budget”. The massive flexibility the MX module introduces means you’re essentially getting two IEMs in one. You get a warm, pleasing bass-cannon plus a near-neutral, cleaner, more technical tuning.
  • The U12t remains my top pick when I’m asked which flagship IEM I would recommend. In this reviewer’s opinion, it is one of the most well-rounded IEMs on the market today and the superstar of the 64 Audio lineup.
  • The Tia Trio is the IEM you’re going to want if you’re looking for a sound that walks the line between smooth and exciting. It is a highly technical IEM with some of the best bass available in an IEM.
  • The U18t is the U12t’s older brother that has been tuned with more of a mainstream appeal. It’s less detailed, less intangibly pleasing, and clocks in at an extra thousand dollars. Need I say more?
  • The Tia Fourte can be safely ignored, as the Tia Trio subverts it for significantly less cost whilst maintaining the majority of the Fourte’s class-leading technical chops. Doesn’t hurt that the Trio’s a whole lot less wonky in the tuning.
1 2 3 4 5
Tonality U12t Nio Tia Trio U18t Tia Fourte
Detail Retrieval Fourte U12t Tia Trio U18t Nio
Imaging U12t U18t Nio Tia Trio Tia Fourte
Dynamics Fourte U12t Nio Tia Trio U18t
Slap Factor Tia Trio U12t Nio Tia Fourte U18t
The Bias Scale U12t Tia Trio Nio U18t Tia Fourte
Cumulative Breakdown U12t Tia Trio Nio Tia Fourte U18t

There are some pros and cons to doing a shootout like this. As a reviewer, I am compelled to draw divides and to rank what I’m hearing. After all, that’s the whole point of a shootout! But the good part is that none of these are bad IEMs when you compare them to the market as a whole. I can think of very few companies that are as consistent as 64 Audio. All of their IEMs have terrific technical performance, and I wouldn’t be surprised to see any one of these IEMs at the top of someone’s list of favorite IEMs. That alone should speak volumes to what 64 Audio has accomplished with their IEMs.

Personally, I’m intrigued to see where 64 Audio goes from here. They’ve just released the U18s, the Yin to the Yang that is the U18t; it’s more of a side-grade for those who didn’t vibe with the U18t very much. Yeah, it’s for people like me, so look forward to that upcoming review. But alongside the U18s, they’ve also teased a couple of other IEMs, one of which looks like it could be sporting a new type of driver technology. Consider me very excited to see what comes next; this is a company that has my attention glued like none other.

IX. Reference Tracks

  • Aimer - Hakuchuumu
  • David Nail - Let It Rain
  • Everglow - DUN DUN
  • Girls’ Generation - Galaxy Supernova
  • Illenium - Broken Ones
  • Joe Nichols - Sunny and 75
  • Keith Urban - Defying Gravity (2009)
  • Sabai - Million Days
  • Sawano Hiroyuki - Best of Vocal Works Remastered (2020)
  • Steve Jablonsky - Arrival To Earth
  • Taeyeon - My Voice (2017)
  • Tiffany - I Just Wanna Dance