DISCLAIMER: Music Sanctuary (64 Audio’s Singaporean distributor) provided me with a discounted price on the A6t in return for my honest opinion. I am not personally affiliated with the companies in any way, nor do I receive any monetary rewards for a positive evaluation. I’d like to thank them and 64 Audio for their kindness and support. The review is as follows.
64 Audio is one of the most well-renowned custom in-ear brands in the world today. Founded in 2010 as 1964Ears, the American enterprise have gone on to become a first-choice for audiophiles and professional musicians – endorsing the likes of Nathan East, Beyoncé, and Kanye West. In addition, they’ve pioneered a staggering number of new technologies. Their apex modules relieve pressure for extended listening comfort and safety, their 3D-Fit process ensures the speed, precision and reliability of 3D-printing, and their open tia drivers deliver crisp, airy and extended highs to every model. Today, we’ll be looking at their new mid-tier referece – the A6t – to see what it brings to audiophiles and engineers alike.
64 Audio A6t
- Driver count: Six balanced-armature drivers
- Impedance: 10Ω @ 1kHz
- Sensitivity: 108dB @ 1mW
- Key features (if any): apex, LID technology, 3D-Fit, tia high driver
- Available form factor(s): Custom acrylic IEM
- Price: $1299
- Website: www.64audio.com
Build and Accessories
The A6t comes in 64 Audio’s standard packaging: A sleeved box adorned with high-res prints and glossy accents on all sides, indicative of the company’s attention to detail and commercial flair. Removing the sleeve reveals the included carrying case, which can be personalised with the owner’s name, as well as custom graphics at an added cost. The case is clamshell-esque with a secure latch for more extreme use cases. Within are the in-ears themselves – with the stock cable securely wound on a post – along with a shirt clip, a cleaning tool and desiccant. At this price point, audiophiles would probably expect a microfibre cloth and an additional mini case, but 64 Audio at least provides all the essentials.
Despite the impressive finish, I’m a tad concerned with the carrying case. There’s a lightweight, plasticky quality to it that screams neither luxury nor security as readily as the ubiquitous Pelican cases do. With products at this caliber, I’d expect sturdier, more metallic elements infused within the plastic. That way, both protection and presentation improve without heavily altering the final MSRP. With that said, the interior of the case was very cleverly thought-out. Each trinket has its own isolated compartment designed for minimal contact (so, nothing bumps against each other). Additional structures were conceived for cable winding, desiccant and extra apex modules – all within an impressively compact form factor.
The in-ears themselves look and feel absolutely remarkable. Despite the 3D-printing process, the shells are impressively clear – more so than most 3D-printed shells I’ve seen – and finish as a whole is great, but not perfect, unfortunately. A couple dull spots, print lines and tiny bubbles prevent a flawless finish. But with that said, lacquer work is great for the most part and these shells are the most robust I’ve experienced yet. They hold a real sense of density and weight that suggests high durability in the long term. The Elmwood Burl inlays react wonderfully to light; highlighting the tiny grains against the surface below. And, the metallic logos are among the cleanest and most sophisticated I’ve seen of its kind.
64 Audio is one of few who’ve transitioned into a fully-computerised manufacturing process. This means the ear moulds are scanned and edited entirely in software, yielding several advantages. Digitised trimming grants superior control and fidelity than hand-trimming. It also allows the user to undo any potential error; impossible with physical impressions. Rather than the traditional wax-dipping stage, the moulds are smoothened digitally as well, which preserves greater detail. Finally, the finished shape is printed in acrylic with its peripheral structures, i.e. the apex port and the tia bore.
Along with advantages throughout production, the 3D-Fit process benefits commercially as well. Digital processing yields faster turnaround times. I received my retail pair within three weeks of placing the order, which is the shortest I’ve had to wait for a custom IEM since my locally-made, similarly-3D-printed Avara Custom AV2. In addition, since my moulds have been stored digitally at 64 Audio HQ, they’ll be able to reuse them for future purchases and guarantee a verbatim fit. This perk may also be offered by non-3D-printing brands, but the perishable nature of their silicone/crystalloid casts means a facsimile fit cannot be guaranteed. And, you may need to send in new impressions after a couple years’ time.
For its many pros however, 3D-printing does have its share of cons. 64 Audio limits their shell colours to five options, which is sorely scarce considering most of the competition offer somewhere between 20-40 standard colours. That figure grows even larger when you include custom-mixed colours, glittered dyes and artistic swirls, which – again – 64 Audio aren’t able to replicate with their current techniques. The 3D-printing process also requires a lot more post-processing than hand-poured shells do, lest they look cloudy and unpleasant. Admittedly, 64 Audio’s clear shells here are fantastic – illustrious and clear. But, it does have dull spots and print lines here and there, so it’s not perfect.
Now, with all this in mind, how do the in-ears fit? Very, very securely. Relative to my other customs, the A6t are far-and-away the most detailed in shape. Part of this is the fidelity of the 3D-Fit manufacturing process; preserving bends and twists that were smoothened down in previous customs. But, it’s also because 64 Audio’s fitting policies shave very little off of the original moulds. They preserve the whole concha and maintain as much girth as possible. On the plus side, this results in a secure fit with zero sloshing noises when I flex my ears, chew or talk. On the other hand, they are rather tight to wear. A slight outward pressure exists when they’re in the ear, followed by slight discomfort after a couple hours. But, this is very much adaptable over time. The discomfort ceases to exist after a week or so of daily wear.
apex technology is pitched as a pressure-relief system designed to rid the ear canal of pneumatic pressure. 64 Audio claims this pressure causes ear fatigue at a faster rate, so apex was developed to grant the user a safer, longer-lasting listening experience. apex comes in two flavours: M15 and M20. The numbers denote the amount of isolation the two modules provide – M15 being -15dB and M20 being -20dB. A solid module (dubbed M26) is offered as well for their earplug range, but is not recommended for use with IEMs because it entirely cancels out apex and dramatically alters sound. Due to the somewhat semi-open nature of this technology as well, 64 Audio promises a wider, more open stage.
In real-life use, the effects of apex are more palpable when you listen at louder-than-average volumes. Personally, I listen at low-to-average SPLs, so ear fatigue sets in rather slowly for non-apex in-ears too. What I can say apex accomplishes is what feels like heightened headroom. For the A6t’s lively signature, the soundscape rarely ever fills overtly saturated or loud. So, although I can’t say it’s a vastly different experience in terms of ear fatigue, I can say that it serves dividends in listening fatigue. Where an energetic signature like this would tire me mentally, the A6t does not most of the time.
With that said, the interchangeable modules do offer great customisability. Switching between the M15 and the M20 yields different bass responses. The former presents a more linear low-end in line with the midrange – ideal for vocal-focused genres. Meanwhile, the latter boosts the sub-100Hz region by a touch. This results in a more forwardly-placed, excited bass response and adds richness to instruments as well. But at the end of the day, it’s worth noting that both offer less isolation than the -26dB that typical non-apex customs offer. If you do prioritise isolation, you may want to either look at other options or invest in a pair of 64 Audio’s EP-C Solid Earplugs which come with the M26 module.
tia stands for tubeless in-ear audio: 64 Audio’s solution towards achieving a crisp, well-extended and resonance-free treble response. Essentially, it’s a balanced-armature tweeter with the top cap removed. So, instead of firing through a spout and into a tube like traditional armatures, the tweeter radiates freely at the tip of the canal. To prevent debris and ear wax from entering and damaging the open driver, a wax guard is securely placed at the very end of the single bore.
Their sonic benefits will be elaborated upon in the next page, but it should be noted that a vacuum designed for in-ear-monitor use is ideal for such a design. This is because using the included cleaning tool to scrape off earwax may instead cause it to break up and fall through the mesh or damage the mesh itself. The immensely popular Jodi-Vac Consumer is an adequate solution, but the included needle was designed for traditional 1-2mm bores; rather than the tia bores. Personally, I’d recommend FIR Audio’s Headphone Vac, which has a larger head specifically designed for these bores.
LID (Linear Impedance Drive) technology is 64 Audio’s solution against frequency response alterations based on output impedance. This is very reminiscent of Custom Art’s FIBAE technology (described here) which guarantees a consistent signature regardless of source. In practice, LID does most of what the packet says. Between my MacBook Pro and my Sony WM1A for example, tonal balance is relatively similar. However, differences in resolution and imaging still exist. Instruments on the WM1A sound more physical and holographic, due to the player’s superior DAC. Nevertheless, it’s a nifty feature, especially for myself as an engineer, where I’m plugging my in-ears into a variety of consoles and amps.