It has come up "elsewhere" :) that someone used a test disc with discrete 7.1 content and DSX Wides and reports that the FL and FR signals came from between the fronts and the respective Wides. That makes sense from what I know. But he reported, somewhat confusingly, that "both the left side ID and the left back ID came out the left rear speaker and like wise for the right side ID and the right back ID came out the right side rear speaker." I say "confusingly" because after questioning, he said affirmative when asked if "the back surround signals came from the side surrounds, and the side surrounds came from the wides."
OK, perhaps he mis-read the questions, but what can you tell us about DSX and any changes in surround and rear surround mapping? And my follow-up is does DSX process discrete tones the same way it does complex sounds, i.e. will what we hear with a test disc be helpful in understanding what happens with actual material?