In reply to:

Some songs (not all) caused the surround speakers to cut in and out like someone was playing with the fade knob and volumes would sometimes vary left and right.


Hmm... So far, I have never experienced that kind of artifacts. My materials are mostly classical, though, meaning that completely "artificial" mixing techniques are very rarely used in the recording process.

chess, are you sure that the artifact is not specific to the DSP and its firmware used in your Onkyo receiver?