64 Audio - Trió

IE600s are notoriously v-shaped IEMs that are pretty far out from neutral with exaggerated bass and treble. In terms of form factor there isn't really a like-for-like replacement for something as small as the IEs. Some additional recommendations worth checking out: Aful Dawn-X, laid-back and natural sound, almost inoffensive. Symphonium Crimson, aggressively fun like the IE600. 4 BAs make it one of the simplest constructions in that price range. Symphonium Europa, a more balanced brother to the Crimson. Letshuoer Mystic 8, very dry tonality but that's also what makes it special. A statement piece of an IEM. Actually close to neutral, as in, most people will find there's too little bass. Yu9 Que, if you could get your hands on one. The hype mainly comes from its price-performance ability and it could absolutely go toe-to-toe with many $1k sets, though I find its tuning stereotypical. It's a solid all-rounder choice if I don't know what your tuning prefs are. 64audio Tia Trio, if you're considering the U12t already you could also consider this. Some of the best bass I've heard in an IEM bar none. U12t sounds boring by comparison. Sony IER-M9, another laid-back oldie and a perennial competitor to the IE600. Depending on where you are, they could be had for cheap. Warm neutral presentation with treble boost, dynamics are its Achilles heel. Thieaudio Valhalla, much more refined v-shape presentation than the Monarch MkIV and more comfortable. Given your budget goes up to $2k, this is very much worth checking out. In terms of fit, Thieaudios are notorious for big shells and contentious comfort, so the advice is always to try before you buy if you could. You'd have the best luck with 64audio, maybe Symphonium, but Symphoniums will take some time getting used to because they aren't vented.

In a nutshell, Tia Trio's wow factor lies in its bass response while U12t's wow factor lies in its imaging. I found the upper treble peak on the U12t its biggest weakness and likely its most controversial aspect, but it's no worse than the IE600's upper treble exaggeration. Truth is, the 'reference-adjacent flagship' sound the U12t targeted has mostly been done better by newer IEMs such as Symphonium Helios or Subtonic Storm. Meanwhile, the Tia Trio's bass is only rivalled by (IMO) the IER-Z1R and the astronomically-priced Brise Audio Fugaku, but both have an even more coloured overall tuning. The common reviewer consensus is that 64audio's A line tends to have excessive bass that makes it sound unbalanced compared to the U line; this makes sense in a loud live session, less so in casual listening. Not exactly an issue if you plan to EQ though. If you've been EQing anyway, may I recommend the dark horse (and my own daily) that is the 7th Acoustics Supernova. Bang-on neutral bass and treble with a relaxed (some would say honky) midrange that could easily be EQed to whatever you want thanks to its smooth frequency response. Resin shell is on the medium-large side but it sits in my ear comfortably, good isolation because of the fit, but even aside from the midrange, its other weaknesses are possible 8k glariness (you need to experiment with tips) and the fact that neutral bass and treble isn't for everyone (Precog mentioned lacking resolution, I'd say it's because he's used to heaps of upper treble in most other flagships. My opinion is if that's the price to pay for balanced tonality, so be it; the resolution isn't that bad anyway). Also, while it's a sturdy resin build, it's also a very small company, so it may be difficult if something does go wrong with it.

I've only tried the U12t and Trio stock for a few minutes, so I can't offer much on that. If you want something fun and bombastic, go for the Trio; if you want something analytical or if you want soundstage, go for the U12t. For me there are only two IEMs right now I would 'upgrade' from the Supernova: Prisma Lumen (which I forgot about while recommending) and the Fugaku. I don't think the Lumen has shipped yet but I heard a pre-production unit at Canjam London and it's the same relaxed neutral tuning with HD6x0-like mids, which fixes the only gripe I had with the Supernova. Since you like Harman tuning the Prisma Lux might be a better choice for you. Fugaku simply because of how it images, despite tonal flaws. And both have comfortable fits. Other than those, I'm content. My bass preference is about 5dB below Harman (and by extension almost every other flagship IEM) and I like a sloping flat line bass curve over a bass shelf curve. I find the Supernova trebley sometimes in the 14k area, which is saying something when almost every other flagship has more treble than the Supernova, so in terms of tuning, I don't have much choice. The only other option I have is Softears but I've never had any luck with their shell design fitting. Supernova also manages to have a good sense of imaging, which is the other thing I have a bias for. So I wouldn't say Supernova is 'king below $1500' especially given the quality of new stuff that's come out, but it still ticks the most number of boxes **for me**.

Diva and trio would be my favourites of the bunch!

Ya I much prefer trio over u12t. Honestly the u6t would be my favourite out of all them if it had dd bass and im most likely going to find another at some point. Then volur and trio are tied for sound but the trio always fit me kinda odd. Honestly that peak sounds a bit odd at first but now I can’t go without it. I always have a 64 audio iem in the arsenal for when I crave that sound

Yeah the 64 audio trio at $2,300.

That’s 64 audio’s whole thing. They built a port with filters into their iems. Essentially acts like having a molded earplug with set db filters (believe they have 12, 15, 20, and solid) that passes signal through it.