The first thing that comes to mind when you see the word Tia in the context of 64 Audio IEMs is treble. Other than Fourté (and the out-of-production Noir), all current 64 Audio IEMs that feature a Tia driver use it solely for treble (whereas Fourté and Noir use a second Tia driver for midrange). And while the concept of an open BA driver is not unique to 64 Audio – Unique Melody created a type of open BA driver prior to Tia – the way it’s been implemented by 64 Audio makes for a very special treble experience indeed. All four hybrids have excellent treble resolution and extension, but each has been tuned very differently, as we’ll see below.
When you’re aiming for easy listening, you can’t have too much treble in the mix, and that’s exactly how Nio rolls. Without necessarily chopping off the highs, Nio’s M15 treble slopes down steadily from 6kHz, occasionally lifting back for some energy before one last ‘peak’ around 17kHz adds a breath of air to proceedings. Switching to mX doesn’t change this tuning much, but because the bass is significantly reduced, what treble energy there is becomes more apparent. Compared to the other three hybrids, Nio has a relaxed but still well extended treble, and its Tia DNA means it doesn’t come across as overly dark either.
Trió unleashes the full force of its Tia treble driver and takes no prisoners in the process. Its treble elevation, which includes lofty peaks at 8kHz (climbing steeply from 6kHz) and another at 10kHz, give the Trió an edgy bite and ‘zing’ that can, on occasion, cross the line between smooth and harsh, and inject some wayward glassiness and the occasional sibilance in female vocals – especially in poor recordings. It also gives Trió its tremendous energy and clarity, extracting maximum detail and creating a vast, almost holographic stage in the process. Thankfully, the majority of Trió’s treble indiscretions are tempered by its subwoofer-like bass, giving Trió a fun V-shaped tuning that literally screams quality.
Fourté’s overall tuning has been the source of much debate in the audiophile community for many years, but if there’s one thing everyone can agree on, it’s the treble. Fourté’s treble is unashamedly huge. It boldly rises above most other frequencies, cresting in a K2-like peak at 8kHz that overshadows Trió and extends far beyond the horizon to give the music a grand and airy scale quite unlike any other IEM. Normally this type of tuning – and this much treble – would render an IEM overly bright or harsh, but Fourté somehow manages to avoid both. Yes, it leans toward bright, but the treble is so well controlled, with so much detail and finesse, that it actually comes across as smooth and lifelike on most occasions. Granted, when playing poor recordings or music that’s been purposefully mastered brighter, Fourté can be unforgiving, so lovers of high-energy, bass-light, bright and edgy music should use Fourté with caution. But give it well-recorded, well-mastered material and you’ll be treated to treble that’s still considered the gold standard by many enthusiasts today.
For anyone who thinks Fourté’s OTT treble can sometimes be too much of a good thing (or just too much), Noir is an interesting alternative. Its treble tuning has been tamed slightly compared to Fourté, with a smaller 8kHz peak that brings the treble in line with the upper mids and bass, allowing the other frequencies to play a much bigger role in the music. The contrast between the Noir’s thicker bass, warmer mids and the still elevated treble is such that when there is a hint of glare in a track, or a bright splash of sound in the middle of a darker recording, it seems to stand out more with Noir. That said, Noir’s superb treble technicalities still elevate it above most other IEMs, and while it’s not quite as airy or ethereal as its twin, it stands head and shoulders above Nio and Trió when it comes to sheer quality.
Def Leppard’s Love Bites off the 2017 remastered 30th Anniversary Edition of the classic album Hysteria, is a litmus test for a brighter recording with high-pitched vocals and multiple crashing cymbals. Nio (M15), with its relaxed treble, gives the chorus [1:50 – 2:12] a cushion of warmth, letting the cymbals wash over your ears like warm spring water, with about as much edginess as you’d expect from warm water washing over your ears. The thickish bassline keeps the brighter notes from going wild, making for a more relaxed version of this ultimately mellow power ballad. Even with mX, Nio doesn’t go OTT with the brightness of this track, the treble having just enough sparkle to be interesting, but not too much that it becomes strident. Trió’s potent bass drums dominate the cymbals so they’re not overly splashy, but it’s the screaming vocals the stand out with greater detail and more energy than either Nio configuration. While I wouldn’t necessarily call Trió bright, I wouldn’t want to turn the volume up too much on this track regardless. Fourté tips the balance in the opposite direction, making the crashing cymbals front and centre and relegating the bass drums to the background. The vocals are also more exposed, but come across smoother than Trió, albeit dominated by the cymbals. If ever you want an example of Fourté’s treble-first approach, this is it, and when combined with imperfect recordings like this one, the brightness can sometimes get too much. This passage illustrates the different approach 64 Audio took with Noir’s overall tuning compared to Fourté. Back come the drums to balance out the cymbals, which, while still bright and detailed, aren’t nearly as forward as they are with Fourté. It also gives the vocals more room to breathe, and while Trió is still fuller and warmer, and Nio even more so, Noir brings just the right mix of energy and clarity, making it the pick of the bunch for me.
Missy Higgins’ Shark Fin Blues, from her 2014 covers album Oz, is my go-to sibilance test for female vocals. With her strong Aussie twang and slightly wispy voice singing the opening lines: “Standing on the deck watching my shadow stretch / The sun pours the shadow upon the deck”, if there’s any sibilance to be heard from an IEM, you’ll hear it. The Nio (M15) has no such problems. The vocals are effortlessly smooth, with a warm and inviting softness that lets you sit back and take in the words without a hint of fatigue. There’s no bass or drums to round off the sibilants either, but switching to mX still doesn’t make the vocals any more “essy” than they can be. Instead, mX renders them with more clarity and a hint more ‘grain’, though not in a bad way. To my surprise, Trió doesn’t show any signs of sibilance on this track either. In fact, I found it slightly less edgy than Nio mX, helped perhaps by the quality of the recording. Further into the track there is a bit more woosh in the vocals, but the added fullness makes Trió’s version a very solid and engaging listen. Fourté is where I thought things might go south, but again to my surprise they did not. Instead, Missy’s voice becomes more airy, almost ethereal, floating across the sharper piano strikes. When she sings “I see the sharks in the water like slicks of ink / Well, there’s one there bigger than a submarine”, there’s a sense that things might be hotting up, and yet she stays on the right side of the sibilance line for me. What I didn’t expect was for Noir to get closer to the line than Fourté (or Trió for that matter), and yet the contrast between the warmer, fuller piano strikes and decay, and the still forward treble of Missy’s trailing consonants, makes them stand out more than they otherwise would.
Angels of Venice’s Trotto, from their self-titled 1999 album, features a colourful combination of unusual mediaeval instruments played with a sparse yet mesmerising rhythm. Large leather drums are offset by a lively whistling flute in the right channel from 1:27 and again (with an even higher pitch) from 3:27, while a stringed instrument evokes both lower and upper treble from 2:27 onwards. All three passages showcase Nio’s (both mX and M15) relaxed treble tuning, but retain a good level of sparkle. The main difference between the two is M15’s heightened warmth and fullness in the drums, which adds more contrast to the treble given the instruments are played relatively far apart from each other in the track. Trió adds more contrast to the mix, the drums becoming larger and more full-bodied, and the whistle and strings (and occasional stick hits on some sort of metal surface) resonating with greater detail. And then there’s Fourté. For all the talk of hot treble, Fourté takes the crispness of the whistle, the texture of the strings, and sharp trailing edge of stick hits and spreads them across a holographic stage, using the faintest of cues to create a vivid, layered soundscape all around the head. Fourté’s world-class detail retrieval is exemplified here, as is its sheer transient speed that effortlessly reveals the physical properties of each instrument. With Noir, the drums return to their Nio and Trió fullness, echoing all over the stage, which overpowers some of the finer details in the whistles and strings. When the track gets really busy around the 3:04 mark, drums going, strings screaming, Noir’s presents a wall of sound interspersed with sparkling highlights, belying a very different tuning to Fourté’s more intricate and layered rendition.
Max Richter’s Winter 1, from his 2012 album Recomposed by Max Richter: Vivaldi, The Four Seasons, is a great example of speed, detail and treble timbre, especially in the violin salvo from 1:15 onward. Nio (M15) makes the strings sound a touch hollow, and not particularly fast either, likely a result of its more relaxed treble tuning and (comparatively) less resolution in this region. Switching to mX, things improve considerably, the strings becoming more rounded and tactile, and also a little faster. Something in the balance between bass, mids and treble prevents this passage from sounding ‘correct’ with the M15, but Nio’s versatility with a module switch means it can better handle a broader range of genres. Trió splits the difference, infusing the strings with more detail and speed than Nio M15 but less finesse than Nio mX to my ears. It’s a touch more strident than I’d like, but still very agreeable. Fourté switches gears and adds layering and complexity to the strings that’s simply not there with Nio or Trió. No longer a contiguous group of violins, I can clearly hear different sections of the strings playing at different speeds in the left (faster) and right (slightly slower) channel, and with the bass more in line with the violins, Fourté creates a sense of depth and space with more air around each instrument and the orchestra as a whole. Noir doesn’t deviate too far from Fourté’s presentation on this track, the strings sounding slightly fuller but with enough detail to differentiate between the groups of violins in each channel. The space around the orchestra is slightly smaller though, the air around the instruments not as black, with a hint of warmth that slows the pace just a little compared to Fourté but makes the whole more cohesive in the process.