I'm at a lost here. Please help me identify the problem that send my speaker to the land of distortion. My Speaker sounded awesome when playing DVD concert from Charlotte Church or any vocal heavy music. But it'll take an 180 degree turn when I pop in a Rock/R&B or Rap CD. It sounded fine for the first couple of minuts and the whole thing just crashed. I thought I have cured the issue when I replace my Int. Amp with NAD C352 and a brand new pioneer CD/DVD player but its started to happen again. I can hear the volume went dim when I watching sound effect heaving musics. Help! 1) Is this the issue with Amp? Does it not have enough backup power to power my 4ohm MB quart speakers? 2) Is this the issue with my AC outlet that can't offer enough power for my Amp? 3) Is this the issue with placement of the speaker? I wouldn't think it'll have this much dramatic effect on them? 4) Bad speakers? Not likely as this is the second pair the vendor replaced for me and the one I returned to them sounded superb now they have it sitting in their showroom. At this point I really feel like seeking professional help to correct my issue before I go nuts. I have spend enough money in trying to correct the issue after I bought these speakers.