I have a recording that is encoded in SQ-quad, but my question deals with all forms of encoded quad. I understand the encoding of rear channels in the stereo mix, where you get a recording quite distinct from the front channels. But what about the front channels themselves? Are they always going to be front+rear? By that I mean, I can run a filter to generate rear channels from front channels, but shouldn't I also have to then "remove" the rear channels from the front mix, so they are also distinct? Or are encoded quad mixes always this way, where the front is actually front+rear, and the rear is read-only? Or is the encoding done in such a way where you don't actually hear the rear mix in the front channels?