Originally Posted by audiofil
RE-0 is my first choice and Soundmagic PL50 a strong 2nd.
Both are very good. RE-0 is very accurate and fast, while PL50 is a more romantic sounding IEM.
PL30 is a very nice choice on a budget, but I wouldn't put timbre amongst it's qualities.
PL30 have really recessed upper-mids which lead to a somewhat weird tonality.
I don't know how you produce this FR-graphs, but my ears tell me that the PL30 sound noticably more true-to-life with classical than the PL50 (BTW I have not even once tried the bass knob). The PL50 are even more mid-centric, quite thick sounding and lack air, plus their upper mids/lower treble have some "metallic" coloring that makes piano sound like someone added 10% of cembalo to the mix. Don't get me wrong, I like the PL50 with most genres and think they are great bang/buck, but I wouldn't recommend them for classical.
Regarding the RE0, I know they have a lot of followers, but their narrow soundstage (only second worst to the SE115, among those I've heard) is IMO a big letdown, at least with orchestra. Plus, the one I auditioned sounded rather squeakish with violin, but I acknowledge that others reported theirs sound great.
Bottom line, I believe classical doesn't get much better than with the PL30 unless you're willing to EQ and/or spend considerably more.