Thanks Mr Sr, but if i send it away to the far northwest. I'll be soundless for a week or more!
I've been reprieved for the time being by jiggling the pot and giving it a clean. As Saab says, I've looked into the idea of swapping the subwoofer out as speakers are speakers, but looking so far at Altec and Logitech stuff, the controls are wired into one of the satellite speakers, so it would require surgery to get them working with my particular setup.
It worries me that what ever follows won't be as good as what I have now, they really are a very good system.