Although my Onkyo TX SR600 offers six channels of amplification for DTS ES and Dolby Digital EX sources, I am only running a Polk 5.1 speaker set up; what is "happening" when I play back a DTS ES soundtrack, say, such as Gladiator, and I do not have that sixth channel? Am I losing any information here? I always prefer choosing the DTS soundtrack over ANY Dolby Digital one because I feel DTS is superior in many ways; but, because I do not have that sixth "back surround" channel (and have set up the receiver to acknowledge there is no back surround channel in the setup menu), is the sound (as I have been told by different people) being kind of "matrixed" into the two back surround channels I have? Is there a "phantom" or "ghost" image appearing if I sit directly between the two back surrounds in which I can hear the sixth channel mixed into the two rear surrounds, or is this just a myth? And just how important is getting a 6.1 setup? 98 percent of my DVD collection offers no more than 5.1 Dolby Digital soundtrack playback...only three discs I can think of offhand offer extended channel playback...Gladiator, Exorcist: The Version Youve Never Seen Before and Episode II: Attack of The Clones (the last two Dolby Digital EX)...am I missing something glass-shattering by not having that back surround channel? Is 6.1, 7.1 and higher going to become more and more the norm toward the future? Right now, I am living in a small studio apartment so I dont think I really need the 6.1 capabilities; and what about these different formats---what is the difference between Dolby Digital EX and DTS ES? Are they just both competing six channel setups?