I've had my 60's for about a week now and they are nowhere near being broken in but I have observed some sibilance on certain source material. What I mean is that kind of "spitty" sound on S's and F's. A good example would be my James Taylor-Live at Beacon Theater DVD on the 2nd track where he sings "Wake up Ssssusssie, put your sshoes on..." I'm wondering if this phenomenon is related to the quality of the source material, the speakers not being broken in or perhaps I could use some better amplification. I am using a Marantz MM-9000 (not bi-wired) to power my Studio 60's and Studio CC. Maybe there is an amp out there that would tame the brightness a little better?? I'd love to hear your opinions. Thanks.