Here's how I would rank the IEMs that I heard so far in terms of all-around SQ:
1) Westone 3 or Shure SE530. I am still undecided at the moment which one is better for sound quality. The Shures are more true to the original recordings overall I think, but Westone 3 is also such a fun IEM to listen to and has better treble and bass extension than the Shures.
2) Sleek Audio SA6 - a fantastic IEM overall. Not quite up there with SE530/W3 in terms of dynamic range and separation, but detail and accuracy are excellent. I especially love how beautiful the midrange is on these and the clarity is the best I've heard in any headphone to date.
and:
Jays Q-jays - heard them briefly. Loved the clear and very detailed sound. Excellent balance across the spectrum, with some slight emphasis on treble. Good dynamics and separation (better than on SA6) Good imaging, but soundstage is very limited in size (not a big flaw for me)
3) Sennheiser IE8 - a bit of a love and hate relationship with this one for me. I loved the full, spacious sound and lush details, as well as good overall accuracy and speed of this IEM. However, I thought that the sound is a bit unbalanced for it to be truly enjoyable - the bass can be overpowering at times and the mids and highs are just a tad too laid back IMO.
4) UE Triple.fi - great bass, great treble. Somewhat unnatural sounding and unbalanced though - has some crossover overlapping issues in the upper bass/low mids area (BIG flaw to my ears!) Blurry midrange (another serious flaw, but this is more of a matter of personal taste). The overall presentation is a tad too dry/sterile for my tastes.
Tied with:
Etymotic ER6 - Yeah, believe it or not, but I only really like them when amped though. In terms of overall balance, it blows away UE Triple.fi IMO and has detail and clarity that's about on par with the very best universals. Soundstage is bigger than on Q-jays and imaging is also very good. Not quite as sophisticated sounding as the very best - can sound a little thin at times and lacks dynamic range compared to the best. A seriously good IEM for the money in my book though.
Other possible tiers for 4th place are Shure SE310, Senn IE7, and Shure E4 and Westone UM2
Ok, I've heard a few others, but I do not own them, so can't really compare them. I just know that they are not as good sounding to my ears as the above mentioned ones. But, here, I'll try to rank them, based on memory:
5) Senn IE6
6) UE Super.fi 3, Super.fi 5 Pro, Head-Direct RE1
7) Senn CX400/500, Head-Direct RE2
8) Westone UM1 and Shure E3
9) Shure E2 and Senn CX300
10) JVC Marshmallow
And of course remember that these ratings are HIGHLY subjective.
