Axiom Home Page Forums General Discussion Home Theater Toy Story 3 clipping

I borrowed this BR from a friend, and when listening to certain loud passages my center channel produced that horrible "Scratchy" sound. When I swithced over to HDMI out from my Oppo it was ok. Then I figured out a DTS HD MA 5.1 track is available also, I switched back to analog with the 5.1 instead of 7.1, and the problem solved. Has anyone experienced anything like that, why would downmixing cause such a problem? I know 7.1 is new, but I hope all future releases contain a 5.1 lossless track as well.