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

Review written by @Precogvision

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: 

• Nio (8BA/1DD) - $1700
• U12t (12BA) - $2000
• Tia Trio (2BA/1DD) - $2300
• U18t (18BA) - $3000
• Tia Fourte (3BA/1DD) - $3600

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. 

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:

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. 

Imaging

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. 

Dynamics 

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.  

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, t