Nathan, fortunately I don't have those problems with the classical CDs that I own, but in the past I experimented with some pop CDs borrowed from the library. This was in response to posts here about "harsh", "bright" etc. Axiom speakers when playing supposedly "well-recorded" items. My finding was that they were by no means well-recorded and seemed to have a boosted response in the upper mid-range/lower treble, possibly to sound more impressive on mediocre equipment. Since one of my receivers has tone controls with variable frequencies, I experimented a bit and found that cutting 4-5dB at the 3KHz or 6KHz points improved things. So, at least on those particular recordings the offending frequencies were a little lower than the 12KHz area shown on your example.
Yes, I certainly wouldn't suggest making some tweak to the speakers which would have a universal effect.
