"Mark Glickman" wrote in message
...
Thanks to everyone for their helpful (and varied) responses.

Rich Wilson and Walt, I'll check the speaker wire. My gut
tells me, however, that it's a bit too coincidental to have
the same problems with four different wires (leading to two
pairs of speakers).

Yes... if the cables are completely separate it's unlikely to be that. I
think I may have got the wrong impression about exactly how your system's
set up!