Exactly, specific bursts of volume on specific discs. Most recently, Back to the Future II everytime the car burst into a new time. Also Fire in the Sky during the "encounter" scene. I forgot to mention I'm using optical inputs. I'll try your suggestions but unfortunately I sent both those discs back already (Netflix).

I'll try all of your suggestions once I find another disc that this problem occurs on. I also should point out that I've had the same speaker setup and wiring for 9 months and only in the past two weeks has this started happening.

After I do some testing I'll let you guys know the results. Thanks.