A few questions regarding Dolby Digital Extended Surround and DTS Extended Surround. 1) Is DD-EX true discrete 6.1? Or is the 6th channel matrix-encoded from Left surround and Right surround only? 2) DTS-ES Matrix is not-true 6.1 (6th channel matrix encoded) while DTS-ES Discrete is true 6.1, right? 3) Is there a true discrete 7.1 encoding (DD or DTS)? Or is the max number of discrete channels upto 6.1? 4) If DD-EX is a matrix 6.1 channel then why are there some DVDs like Gladiator which have DD-EX on them? I would assume that ALL 5.1 DVDs would also be 6.1 DVDs (and 7.1) if one has the right receiver and right number of speakers? 5) If I want to setup a 7.1 HT, should I necessarily look at a THX-certified receiver because Extended Surround was invented by THX/Dolby Labs, I believe? Or will something like Denon AVR1082 which has 7 discrete amplifiers suffice?