Amer, although what Greg and semi say about some 7 channel receivers applying special processing to the 6th channel so that the two rear-surround speakers wouldn't get exactly identical material is entirely correct, I'll stay with the point I proposed to you. Generally, when the special processing isn't applied, both rear surrounds get exactly the same information from the monaural 6th channel, which is as it was designed to be. Since the term "pseudo" indicates a simulation or fake of something real,and since no 7.1 format exists, the term "pseudo 7.1" is an oxymoron.
Although it's now a bit dated, you might be interested in reading the face-off between various surround configurations which these guys
ran .
