the difference of the back soundstage (effects) and front soundstage (dialog), is THE difference. the front soundstage is exponentially more important than the rear. 6.1 has one rear mono channel, 7.1 has basically a stereo pair of rear channels, having 2 center speakers is not really the same, because they are not in stereo, they are producing the same sound. although so closely as to negatively impact each others sound.

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