My thoughts as well gonk. The composite was an older (15+ years) monster cable built for directional signal flow, and it's possible it was reversed. Couldn't reproduce the distortion yesterday but I was playing with a different input (CATV). Will have time to experiment with the original (CD) source again tonight. The M80's were a half foot closer but still at least two feet away originally and the sub (which evidently was the radiating source of interference) has always been 10 ft. Thanks for your help - will update after the sony service call.