Rick, i doubt power is a problem here. It certainly has nothing to do with "dirty power" like was suggested by sutter over at the Spot. That is all marketing jargon reiterated.
When you balanced your speakers for SPL, were the surround signals jacked up at all?
How far away are the speaker runs and what gauge cable are you using?
Have you tried swapping out for your other receiver unit to see if that also produces the sound?
Have tried different cds, dvds?
Hopefully someone else can chime in. I'm short on time today.
