I will switch amps on the mains and see if that sheds any light, thanks. I checked the balanced switch and that was ok. IL30 mains are 8ohm as are the LM1 surrounds.

They are connected with different wire (14ga in-wall for surrounds and 10ga SK for fronts), but again, that was a pre-existing condition.

I've also noticed that the input settings on the 950 seen to occasionally change. For example, I was just setting up the xbox for the kids and it was set on coax 1 instead of optical 1 as it should. We haven't used it since before the storm last week.

I'll do some more tinkering. Thanks for the feedback Gonk.