thanks for replies, i did no work prior to the sound going on the stereo, and there is no aftermarket amp fitted.
the sound was a little intermittant the day before, then just stopped, everything else works on stereo.
thanks for info on ATT, at least i don't have to worry about that...i'll just have to have a good look at all connections again, but they appear to be connected. when i took it out i was hoping to find a loose speaker connection....
the stereo is a Sony CDX-4180R