Nick, there's no relationship between digital compression(e.g. the DD or DTS audio in regular DVDs)and applying a processing mode such as DPLIIx to send some of the surround material from the side surround channels to back surround speakers. If a format is uncompressed(e.g. regular CDs, some sound on BluRays), that's inherent in the format and can't change.

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Enjoy the music, not the equipment.