64 Audio U6t Review

64 Audio has a vast array of custom IEMs designed for professional use on stage and in the studio. From among those custom options, they've selected IEMs with high crossover potential for audiophiles to release in a universal fit version. The A6t was among their most popular custom models ever, and now the U6t brings that same sound to a wider audience.

The Build and Design

U6t features a lightweight body, with a glossy 64 Audio logo emblazoned on the faceplate. The overall shape and design is quite simple, and provides an easy, comfortable fit. U6t uses 64 Audio’s Apex technology, so the amount of noise isolation and the specifics of the bass response can be balanced through the use of Apex modules which control the amount of air that’s vented.

64 Audio U6t

The package includes a nice selection of ear tips, with foam, standard silicone, and SpinFit tips. There’s also a leather wrapped case, wire clip, and a cleaning tool. Perhaps most notable to longtime 64 Audio fans is the new cable. U6t uses a different cable design than previous models, and the materials definitely feel like an upgrade. Gone is the stiff memory wire and tangle prone qualities of the old cable. The new one is softer to the touch and has a more premium look befitting of IEMs in this class.

The Sound

The U6t is an absolutely impeccably tuned IEM that sounded great with virtually everything I threw at it. It’s clearly inspired by the U12t – with possibly a bit of the U18s in there as well – and delivers a balanced musical sound. There’s a natural depth and impact in the bass, good positioning of instruments and vocals in the midrange, and a treble which is well balanced with the rest of the mix. The technical aspects can’t quite match U12t levels, but with only half the number of drivers, it does make you wonder if some of those drivers in the U12t aren’t working particularly hard.

The bass is very similar to the U12t in its presentation. There’s a small emphasis in the midbass on down, that rolls off into the subbass, providing some punch and a good sense of depth, but not the deep rumble of a more emphasized subbass. There’s strong coherence in the bass and lower mids, providing a very lifelike sense of detail in percussion and bass instruments.

64 Audio U6t

The mids are slightly pulled back, but not recessed, while the upper mids have some lift to provide excellent vocal performance, and good weight for midrange focused instruments like guitars and pianos.

The treble gives you some air in female vocals as well as a good feeling of splash and sizzle from cymbals. It’s somewhere between smooth and bright, where you still get that sound of crisp detail, but it’s not as airy or bright as it could be. The soundstage is moderately sized with particularly good depth. The imaging has a holographic feeling with pinpoint positioning and strong separation.

The Black Keys’ “Thickfreakness” exists in an odd space as a deliberately low-fi sounding recording that actually has solid production behind the scenes. As such, the U6t reveals small details and imperfections all over the recording from squeaky fret noise to peaking vocals, but each of those things exists as part of an aesthetic, rather than being the fault of a bad recording. U6t delivers the deliberately “bad” aspects off the recording, like the scratchiness in the over-distorted guitar, in stunning detail. The quality of the drums revealed by the U6t, with crisp cymbal crashes, snappy snare hits, and detailed sounding toms, helps let you in on the fact that this recording is actually quite good.

The U6t provides strong separation and layering for decoding the complex chords in the opening to Michael Mantler’s “Folly Suite.” Throughout, there is a transparency to the instrument delivery. The strings sound alternatively silky and sharp while the trumpet cuts through the mix with a smooth but strong presence. The tension between melody and dissonance are delivered with the right balance of a musical and an analytical nature to enable the listener to wrap their head around the piece's harmonic complexity while keeping the timbre natural, and delivery balanced.

64 Audio U6t

“Californian Soil” by London Grammar starts with sounds and vocals that appear from all directions, orienting the listener to the size of the soundstage and demonstrating the strong imaging capabilities of the U6t. There’s a deep textured bass layered with a tight impact from the bass drum, along with assorted percussion that bounce from left to right. The lead vocal has good presence and weight as the singer is flanked by strings and synthesizers that create a broad soundscape.

Cuban reggaeton protest song “Patria y Vida” provides an example of how the U6t can provide a deep satisfying subbass coupled with a solid low end punch that works well in a variety electronic genres and hip hop. As someone who’s Spanish is a little rusty, the strong vocal presentation and detail provides a crisp enough delivery of the rapped Spanish that I understood quite a bit of the lyrics as well. The acoustic guitar that carries the melodic hooks has a nice smooth attack on the high notes, and a rich sound throughout.

Comparisons: Campfire Audio Andromeda, Noble Audio Zephyr

The $1000-$1500 price range is honestly a pretty incredible place for IEMs. To compare the U6t, we have one of the most well-loved IEMs of all time – the Campfire Andromeda – and one that’s a bit more niche, but quite good – the Noble Audio Zephyr.

In the bass, Andromeda and U6t are a bit more tuned, with a more prominent midbass and a rolloff into the subbass. Zephyr is more linear with less punch (despite being the only IEM of the three to feature a dynamic driver), but a deeper extension into the subbass. The mids are more similar with each possessing strong layering and great coherence. In the treble U6t and Andromeda have a touch more sparkle, where Zephyr feels a little smoother, with a strong presentation of the treble ranges for instruments like violins or electric guitars, but less air overall.

64 AUdio U6t Noble Zephyr

In terms of the instrument timbre, Zephyr is the most natural, and U6t comes close. Andromeda does sound generally natural, but there’s an organic element to Zephyr in particular that lends an intense realism to the music.

For the soundstage, Andromeda is sort of the baseline between the three, where U6t and Zephyr match the general depth and width, but U6t has a bit more depth, while Zephyr has incredible width. All three also have holographic imaging, with the U6t pulling ahead slightly with its precise, crystal clear imaging.

The Bottom Line

If you were hoping for U12t scaled down to a lower price point, U6t delivers exactly that. The U6t continues 64 Audio’s tradition of creating IEMs that balance reference level detail and strong musicality for an experience that blurs the line between analytical and emotional.