I have a issue with my AV Connection. Each time I change a DSP from my YAMAHA amp or fwd / rewind / stop my dvd player, a loud thud noise erupts from my Mission subwoofer. I know that my equipment is fine but am bewildered as to why this happens. I have an incling that its due to my set-up. Basically, I have a s-video / optical connection and the other connections are the subwoofer lead (cambridge) and scart for tv-video. Please advise as im going insane in the mem-brain!!!!