Brief Review – 64 Audio Fourté


The 64 Audio Fourté was received on loan from

A little over a year ago, 64 Audio made waves by announcing two new flagships: the Fourté and A18. While both iems seemed to raise the boundaries of pricing to new levels, they were bolstered by the implementation of new tech: the TIA drivers. By removing the roof of balanced armature drivers and using a tubeless design, the TIA drivers offer an impressive top-end extension, albeit it with a brighter treble tone.

Sound Impressions

The Fourté’s specs inform us of a rather unique design; a hybrid between a traditional dynamic driver, and 64’s advanced TIA drivers. A disparate technology, that, maybe unsurprisingly, returns in its sound: where its bright treble notes are screaming ‘go faster!’, the bass keeps urging everyone to calm down. It’s a contrast that returns throughout its a presentation, a ying and yang of opposing forces, which provide a measured balance between bright and warm, quick and slow, and advanced versus contemporary.

Down low, the Fourté’s bass displays several revered characteristics of a dynamic driver: an analogue quality compared to BA drivers, with a more realistic texture. It’s a bass that’s primarily centered on mid- over sub-bass.  Fourté’s low end isn’t bassy, but I would equally be hesitant to describe it as lean; it outputs a sufficient quantity to let its presence be felt, while providing a warmer tone. As its bottom-end extension is only average at best, it’s not necessarily visceral in terms of impact, especially when compared to dynamic drivers as the Galaxy or Dream. And as the definition of the mid-bass is only moderate, it doesn’t present itself as a particularly technically bass – especially since its somewhat lengthy decay relaxes the pace of the music, and warms the stage. So quite frankly, there isn’t much going on here to suggest this is an above average bass in its overall performance.

However, this can be in part attributed to the cable pairing. Switching Fourté’s stock cable to a quality silver-alloy like the HSA Venom or EA Horus noticeably improves the control of the bass, resulting in a tighter bass response. Accordingly, Fourté creates an airier stage, as well as more transparent, albeit leaner midrange. Even so, tightening the bass loosens the restraint of the treble, resulting in sharper treble notes. In that sense, Fourté’s bass also provides a rather practical functionality, by balancing the brightness of the treble tones, as well as adding body to its midrange notes. The midrange itself consists of a subtle bump around 1-2 KHz, followed by a dip throughout its upper midrange. Accordingly, the instrument notes are primarily constructed by of a thickness from the bass, rather than density from the midrange frequencies.

This returns in its vocal presentation. Fourté creates neutral vocals in terms of forwardness, which are centered within its spacious, three-dimensional stage. As a result of the midrange bump, they are sufficiently grounded within the stage. At the same time, the lack of upper midrange presence prevents them from sounding completely captivating – there isn’t a great deal of power behind the vocal. Even so, they don’t feel amiss either; Fourté’s midrange has sufficient size to sound engaging, so it doesn’t sound lean. It’s a rather neutral midrange in size and forwardness, which seems to work in unison with the bass. And importantly, it has a lightly warm tone.

But Fourté’s magic resides in its treble. Fourté’s treble is without a doubt, the most revealing of its kind – and accordingly, its unique selling point. Relying on a combination of excellent extension and sheer brightness, it is quick, high in definition, and hyper-detailed. But Fourté’s treble is a double-edged blade: the improved extension boosts its resolution, and opens up its stage. But suffice to say, it is equally one of the brightest trebles in the top-tier range, if not the brightest of all. Make no mistake, Fourté is not for the faint-hearted; it provides a stunning amount of detail, but there can be a price to pay – especially for the treble-sensitive listeners among us. With the wrong pairing, its 10 KHz peak can result in a more aggressive attack of its treble notes.


64 Audio A18
The most requested comparison is probably with its sibling and co-flagship, the A18. Fourté and A18 share some general characteristics due to their TIA treble driver, but are overall more different than similar. For starters, fans of dynamic bass will be served by Fourté; Fourté has the more analogue bass, with its characteristics dynamic qualities. Even so, the A18’s bass is greater in mid-bass quantity (with M20 module), but significantly quicker in decay. So overall, the A18 sounds faster, where the Fourté’s slower decay relaxes the pace. Furthermore, while the A18’s lower midrange is slightly laidback, its upper mids are relatively more forward. As a result, the A18 has a more forward vocal presentation, positioned in a primarily wide stage. Fourté’s midrange is relatively neutral in size, and centered within a three-dimensional stage with even proportions.

Overall, the A18 has the more linear signature, which I personally prefer in terms of tonality and presentation. And where the Fourté’s treble actively probes the limits of my tolerance, the A18 has never given me issues. That being said, the Fourté is the more detailed of the two, revealing every micro-detail the music has to offer – this is where the Fourté truly excels. So for music fans in pursuit of a sense of ‘hyper-realism’, the Fourté will be the easier choice.

Empire Ears Legend-X
The two flagships make for a compelling comparison, due to their hybrid configurations: the Fourté with its single dynamic driver and TIA balanced armatures, and the Legend-X with its double dynamic bass supported by five balanced armatures. In terms of bass, the Legend-X has the greater bottom-end extension, with its emphasis leaning on sub- over mid-bass, although it is full-bodied in its presence. Accordingly, the Legend’s bass is tighter, is higher in definition, while being more impactful. By comparison, the Fourté’s bass is warmer, and a bit more natural in tone. Even so, most points go to the Legend-X.

Their midrange’s are again very different. Fourté’s midrange is warmer, with slightly thicker notes pursuant to its mid-bass tuning. By comparison, the Legend’s midrange is positioned slightly more laidback, but it is significantly denser, due to a lift in its upper midrange frequencies. In addition, it is more neutral in tone. Accordingly, the Legend’s midrange sounds clearer and more solidified, albeit in a slightly more distant position. The Fourté’s midrange is warmer, and a bit thicker. Both iems can be considered bright for sensitive listeners; the Legend due to its prominent lower treble peak, and the Fourté due it its 10 KHz peak. Overall, the Legend can be considered neutral with a slight touch of brightness. The Fourté in turn has the warmer stage structure, from which brighter treble notes arise.

Concluding thoughts

64 Audio’s Fourté is a unique hybrid, with the implementation of two types of drivers serving as a counterweight to balance its tone: the warm undertone of the dynamic drivers, versus the brighter TIA drivers up top. It’s a rather precarious balance that allows a certain versatility for the user, as different setups lead to different paths. However, even with the warm and smooth SP1000 Cu, the Fourté’s treble continuously dazzles me, but probes the limits of my tolerance. It’s like when your body is all knotted up, so you tell a masseuse to dig in and give you her best. Most of the time you’re thinking “ah, that hits the spot”, but occasionally you cry out “dear lord woman, are you trying to murder me??” – Fourté’s treble in a nutshell.

An often heard question considering its price and novel technology, is ‘is Fourté the best?’. The answer is quite simple: the Fourté is the best in what it does. That is, providing a detailed sound, with an extraordinary ability to uncover micro-detail. Many of us dove into this hobby after the first time an earphone managed to provide a new level of experience, the proverbial ‘lifting a curtain’, offering a new insight to our music. Fourté won’t be considered the smoothest iem any time soon, or have the most natural treble tone – but its most profound quality is its ability to provide a similar experience, even for seasoned listeners.

64 Audio Fourté
Configuration: 3 + 1 Hybrid
MRSP: $3599 is a registered Dutch dealer for brands as Focal, Audeze, 64 Audio, Empire Ears, EarSonics, Campfire, and Effect Audio. However, where applicable they ship throughout Europe. 


About Author

Nic is currently in pursuit of a PhD degree in social neuropsychology, while trying not to get too distracted by this hobby. In pursuit of theoretical knowledge by day, and audiophile excellence at night. Luckily for him, both activities are not mutually exclusive which helps to lighten the workload. Always on the go, Nic's enthusiasm for hi-fi is focused on all chains of the portable system: iems, cables and daps.


  1. Hey there flinkenick, have had a chance to listen to u12t or trio, if so which would be good for something like rnb, hippop, vovals, acoustic and just house, if you could give some description of their sounds and what you thought of each might also help the fourte is far too expensive for me to be honest

  2. I can’t thank you enough sir for your effort and time to give us the definitive review for the tia Fourté. I can now rest in peace!

    So, you say that treble is what listeners should be worried about? I knew from the start not to pair Fourté to a neutral/bright source. My proposed pairing would’ve been to a slightly warm Chord Mojo, or to the warmer and smoother Sony NW-WM1Z. If Fourté has anything like the infamous Sennheiser HD800 6K treble peak, then that shouldn’t be a problem for me! I’m however wise enough to know to try before I buy. Honesty, I was more worried about Fourté having a thumping bass slam, but you put my fears to rest!! Yup. I’m that opposite-end-of-the-spectrum sensitive.

    My summary to your review in short: “A desperate attempt to control a precarious balancing act”. That masseuse analogy is just genius.. it put a wide smile on my face and made my day. It clarified everything for me. Your brief review puts my two months “tia-equipped IEMs” research to its end. I now fully understand what tia Fourté is. Its beauty is flawed, so anyone seeking it must understand its quirks before taking the plunge.

    • Thank you for the kind words yourself, dear sir. For most people Fourte’s treble will be fine – only sensitive listeners should take heed. Personally, I am not bothered by it. Only with a brighter source or cable I test my limits. The bass itself is present, but not overpowering. The WM1Z with a nice balanced cable would indeed be a good pairing, but if you identify as a treble-head the WM1Z itself might be too warm for you. From memory the Mojo would also match well, but it’s been a good two years since I heard it hehe.

    • yes a problem I find with music reviewers is that they describe the sound but do not address what kind of music they are listening to and thats really important for us readers to know.

      • Most certainly. I exclusively listen to Scottish Pirate Metal. But sometimes, I like to spice it up with Mongolian Throat Singing Rap.

        • Ok, but it would be really nice if you described the sound characteristics not in a general fashion but with a songs as a reference in comming reviews, especially when compairing against other iems.

          just makes it a little more tangible.

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