Review written by @Precogvision
64 Audio. So, it’s no secret that this is one of my favorite brands; 64 Audio is consistently at the forefront of the bleeding edge, setting a precedent for the flagship IEM market in this reviewer’s opinion. But while they have no less than five flagship-worthy IEMs in their lineup, there is one IEM that towers above the rest: the Tia Fourte. The Fourte is the brand’s tour de force, 4-driver behemoth that clocks in at a hefty $3600. Heck, I believe this was one of the most expensive IEMs, if not the most expensive IEM on the market at the time of its release. But price aside, I’d argue that this is the most difficult IEM to love out of the 64 Audio lineup - read on to find out why.
Source & Drivability
All critical listening was done off of an iBasso DX160 (volume ~10), A&K SP1000M, and iFi Micro iDSD BL (through Audirvana) with lossless FLAC files. I used a standard 0.78mm cable and SpinFit CP100 tips. Unlike many of the other 64 Audio IEMs I’ve heard, the Fourte is not source-agnostic (at least when it comes to frequency response) and it is somewhat more sensitive.
The Fourte’s presentation is a sparse one and, if you ask me, somewhat unbefitting of such an expensive IEM. You’re presented with a large, cardboard box, and inside you’re greeted by the two halves of a pleather hockey-puck case. One half contains the Fourte nested in foam, and the other half contains the various accessories underneath. Said accessories include the following:
- Leather Hockey-Puck case
- 0.78mm, 48” Premium cable
- TrueFidelity Foam eartips (s/m/l)
- Silicone eartips (s/m/l)
- 64 Audio sticker
Now, I know I sound like a broken record at this point - especially if you’ve read my other 64 Audio IEM reviews - but I’d really like to see 64 Audio up their accessories and presentation game. The hockey-puck case isn’t real leather for starters. It uses “imitation” or “simulation” leather which, if you are not familiar with the grades of leather, is the cheapest possible form of leather. It often consists of trace particles of leather mixed with plastic and other materials to offset production cost. It will neither patina, nor will it wear gracefully with age like full-grain leather. So, I think 64 Audio’s aluminum puck case or Pelican case with custom foam inserts would have been more appropriate for such an expensive IEM.
In what must be second-nature at this point, I also didn’t even touch the stock cable, opting - immediately - to use a more pliable one. The stock cable is rough, almost paper-like in tactility, and the memory wire exacerbates the strain on the IEM’s connector joints. Maybe this type of cable is great if you’re performing on stage, but the Fourte will likely be used in a more personal capacity in accordance with its target demographic. Oh - and wait for it - did I mention this all coming from someone who actually paid for and owns a couple of 64 Audio IEMs?
The Fourte itself sports CNC milled, aluminum shells with “copper patina” faceplates on top. I don’t believe these are faceplates made out of actual copper - it’s more so a reference to the aesthetic - at least based tactile feedback. Of course, this is just speculation on my front. For fit and comfort, at least, the 64 Audio IEMs are top-notch. Their IEMs sport a teardrop frame and utilize the company’s Apex (air-pressure-exchange) technology. For those who might not be familiar with this technology, in laymans terms, it releases the pressure that builds-up over prolonged periods of listening with IEMs. This is an extremely practical, quality-of-life feature that I cannot attest enough to. I believe the trade-off is a minor loss of isolation (although I don’t regularly take such expensive IEMs outside for obvious reasons!).
Editors note - 64 Audio have confirmed that the Fourte does use a copper faceplate, but that it's also coated to prevent damage from aging.
But how does the Fourte actually sound? Well, you’ll get a kick out of this: The Fourte just might be one of the most dynamic IEMs I have heard. The way the Fourte scales dynamic swings is borderline guttural. At 0:56, when Illenium's "Broken Ones" transitions into the drop, there’s a sink to the cadence, like the Fourte is breathing in; you can just feel the shift and energy that's about to slam you. It's not about the sheer contrast here - macrodynamics - so much as it is the vibrancy, vigor, and weight - so dynamics, dynamics - with which the Fourte articulates swings. Either way you cut it, though, the Fourte takes top marks; it would not be an understatement to say that the Fourte is without peer in these metrics.
And that’s not all. This wouldn’t be a Fourte review if we didn’t talk about its lauded imaging chops. If you’ve read any of my reviews before, then I’m sure you already know my thoughts on imaging: The vast majority of IEMs fall within the realms of average, and the IEMs that actually exhibit the image distinction, incision, to qualify the oft-misused buzzword “holographic” are extremely rare.
Needless to say the Fourte is one of the few and far between. Running it through some of my usual test tracks on Sawano Hiroyuki’s “Best of Vocal Works” album, I couldn’t help but find myself nodding along. The Fourte exhibits excellent left-right channel distinction, and center image diffusal - including the center corners - is ample, case in point the violins panned to the far reaches of the stage on “Binary Star”. Steve Jablonsky’s “Arrival to Earth” also displays good amounts of backwards imaging to the chorus at 3:16 and when the kettle drums enter shortly after. There does appear to be a lack of incision in the center image of sorts - which I’ll explore more closely below - but by most accounts, the Fourte sets a strong benchmark for imaging in this reviewer’s opinion.
By way of more traditional technicalities, a misconception I see quite often is that the more BA (balanced-armature) drivers that you can cram into an IEM, the more detailed it will sound. After all, a BA driver is but 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. Ultimately, implementation reigns supreme; the Fourte exemplifies this sentiment and puts to shame many high-count BA configurations I’ve heard.
Like so, detail retrieval on the Fourte is nothing short of astounding. Something that becomes increasingly evident as you listen to more IEMs is that not all BA drivers are created equal. To this end, there appears to be a sort of micro-texture present to the Fourte’s midrange, likely a result of 64 Audio’s tia drivers. I generally avoid hyperboles like “wet” or “moist,” but here, I’d wager they’re appropriate. This sort of transient behavior often goes hand-in-hand with microdynamics; I find myself glued trying to discern more of this texture. It certainly doesn’t hurt that BA timbre - a sort of metallic smearing to note decay - is minimal like most of the 64 Audio’s IEMs.
So I’ve heaped praise after praise upon the Fourte. That never happens in my reviews; surely you say, there’s a catch. Well, yes, there is a catch. And it’s a pretty big one: tonality. The Fourte is unabashedly colored in its presentation at the expense of tonal accuracy. Pin-pointing why is no easy task, but I’ll do my best to break down the specifics.
Frequency response measured off of an IEC-711 coupler. There is a resonance peak at 8kHz; as such, measurements after this point should not be considered entirely accurate. It’s also worth noting that the coupler is only certified up until around 10kHz.
Starting with the bass, the Fourte exhibits a strong sub-bass emphasis up until around 200hZ. The bass on the Fourte is decent, but by no means what I would qualify as “best-in-class”. I do find myself preferring the bass on 64 Audio’s own excellent Tia Trió. To this end, while decay is about equidistant between the two IEMs, transient attack favors the Trio. The Fourte’s subwoofer also exhibits an inflated quality to the way it slams, not dissimilar to some less-capable dynamic drivers I’ve heard. One might suggest that this lends to the Fourte’s grandiose presentation; however, I would be remiss to ignore the Fourte’s bass deficiencies in isolation.
The midrange is where things get interesting to say the least. You can see from the graph that the Fourte exhibits a strong dip from around 600-1000hZ before rising for the ear compensation, after which it dips again from 3-4kHz. These sorts of dips in frequency response can often impart a sense of spaciousness, and I suspect there is a similar behavior going on with the Fourte. You’ll recall my earlier comment about the center image lacking “incision”. I had to do a lot of listening to figure out what was throwing it off for me, and even then, it’s difficult to articulate. On Sawano Hiroyuki’s “Cry,” perceived soundstage depth is exceptional, but there appears to be a disconnect between the placement of the vocalist, Mizuki, and when the drums enter from the far back at 0:22. Image distinction is somewhat discombobulated, skewed upwards and hollow on the vocalist, fuzzy in the far reaches of the stage and not quite resonating as sonic-wall free as on something like the U12t.
And then, as I alluded to earlier, there are the tonal inaccuracies that plague the Fourte’s midrange. On “Amen” by Edens Edge, the vocalist, Hannah Blaylock, has a pronounced nasal quality to her voice. Instruments simply do not sound correct, either. While this might seem like a cop-out, it’s not a case of just certain instruments, so much as it is most all instruments not sounding tonally accurate. Of course, this also isn’t helped by the treble.
Treble on the Fourte is not dissimilar to the Tia Trió to my ears. Stick impact remains slightly recessed, and there’s good amounts of crash followed by a recession from around 10kHz to 14kHz in the lower air frequencies. But of course, this wouldn’t be a 64 Audio IEM without the infamous Tia treble peaks; the Fourte peaks strongly from 15-17kHz. Bear in mind that the IEC-711 coupler is not accurate after 10kHz, so as usual, I verified this by ear with sine sweeps. A lot of people will cite the treble as the Fourte’s biggest dealbreaker, but for whatever reason, I don’t find the Fourte’s treble particularly offensive. This elevated quality certainly does wonders for the Fourte’s perception of detail, as I frequently hear faint treble resonances and minutia that I don’t recall hearing on many other flagship heavy-hitters.
Clearly, there are a number of reasons why the Fourte is a tough recommendation. 64 Audio hasn’t made this any easier on themselves, either. The Fourte faces stiff competition from none other than its younger brother, the Tia Trió. In my opinion, the Trio is actually the more mature of the two IEMs. Sure, you have some minor cutbacks in technical performance - namely imaging and the Fourte’s terrific dynamic range - but the Trio’s tuning is a good deal more balanced whilst maintaining much of what makes the Fourte great. And as I alluded to earlier, the dynamic driver used in the Trio seems to be more capable; I’d confidently put the Trio in my Top 3 IEMs for bass.
Still, there are times when you want colored sound. I can’t get enough of the Fourte on stuff like Slander & Au5’s “Anywhere” and Dreamcatcher’s “Can’t Get You Out of My Mind”. On these tracks, the Fourte presents sound so unabashedly colored, so tonally wrong it’s almost good. While such instances by no means refute its shortcomings, the Fourte is somewhat maligned and misunderstood in my eyes. To this end, there is the expectation of making a statement with your tour de force IEM, and if 64 Audio could capture the Fourte’s impressive technical prowess in a more tonally balanced IEM, I think they’d have a real winner on their hands.
- Aimer - Hakuchuumu
- David Nail - Let It Rain
- Dreamcatcher - Silent Night
- 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
Watch the video review here: