It's not just the source material. It could be the room. Could be the tweeters. I have brought my M60s and amp into a dealer who had a nice room setup and didn't hear sibilance on material for which I do hear sibilance at home. In the case of this source material, the sibilance was probably cause by my room. The tweeters in Axiom speakers, while perhaps not hurting, certainly do not help. Axiom needs to improve in this area or offer a more expensive line which contains this improvement. Of course, if you always believe it's the source material then you have found your perfect speaker. lol