IER-M9

full sized. I pick my hd660s and even my hd620s over my ier m9 anytime

I prefer my fiio fd15 compared to my Sony IER M9. The vocals on the fd15 is top notch

I have a tanchjim bunny, fd15 and ier m9, all three are from different categories and different price points. Yes, ier m9 are superior in every aspect you can think of except the soundstage. Although I love the m9, I honestly think both my hd660s and hd620s are superior in terms of listening experience, enjoyability and comfort.

What's your budget if you have the funds my recommendation is the Sony IER -M9.

It should be fine as long as you don't try to deep insert them if you are using silicone tips. Divinus velvets, acoustune aex70, xelastecs, and both baroque tips work for me, but that mostly depends on your ears. The eartips should seal enough to not create a vaccum seal. The downside with silicone tips and the m9 is that noise isolation is much worse compared to foam tips.

I would recommend demoing the m9 if you can. I find that the sound changes quite a bit depending on the eartips. Also, the textured coating could be uncomfortable.

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.

Supernova's nozzles have a small lip and I've had no problem fitting tips, though its nozzle size means you'd need some persuading for smaller tip nozzles. Might be a camera angle issue because it's not that noticeable with black resin. It's also available in plain black if that's your jam. I prefer using [B&K 5128 graphs](https://graph.hangout.audio/iem/5128/?share=JM-1_Target,Supernova,IE600&bass=0&tilt=-0.7&treble=0&ear=0) for comparing because it's a better measuring rig but I also understand Crin doesn't have measurements of the U12t or the tia trio on the 5128. U12t has physical modules that let you adjust the amount of bass so that might be worth checking out before you even consider EQ, [Precog's graphs](https://precog.squig.link/?share=IEF_Comp_Target,64_Audio_U12t_S3_\(M20\),64_Audio_Tia_Trio,64_Audio_U12t_S3_\(M15\),64_Audio_U12t_S3_\(MX\)) give a good idea of the differences. You can't determine bass 'quality' on driver type alone. While the tia trio does have 'better' bass than the U12t IMO, by no means does this mean the U12t has 'bad' bass. It's still rich and powerful and outperforms many DDs out there, and the same goes for its little brother the U6t. Also depending on where you are, for all of the IEMs discussed, go used if you're willing to. You might get a better deal because they are relatively old.

Ier m9 they really are that perfect I have no comments or downsides. Truly my favorite pair Soft ears studio 4 , top level separation and vocals at such a reasonable price point

I like neutral with sub-bass boost though a well-executed warm tuning I can get behind as well. I used to have a set of Sony IER-M9s before I sold them, and those have a pretty notable midbass boost.

I have the Sony IER-M9 at the moment, which I really enjoy. But some new ones would always be cool