Well, Let me say this not sure beyond what a phase invert will do accept cause the amp to go out of phase to the speaker and possibly suck sound out of certain situations... BUT the Invert at the Digital domain is absolutly necessary if you hear it, It inverts the "1's" and "0's" at the recorded disk and 99% of the discs I have sound far better inverted than standard, much fuller and more analog like, this is because I found out after owning a device that does it that many recordings are mixed out of phase right at the studio, Why? No clue but it works, I have only seen this on fairly pricey players however.