My first thought is the same as sushi's. I would guess you're finally hearing all the horrible crap in "pop" recording due to finally owning an accurate pair of speakers. You can get a little resistor from Axiom that clips into the tweeter and drops the gain a bit, dulling the highs if you want. The fact that this doesn't appear to you in classical CD's which are usually better recordings due to the audience makes me think it's the other recordings that are the problem.

What equipment were you using prior to owning the M22ti's?