Hi, I just got a THX certified reciever, and have a few questions about new sound modes. Like: Dolby Digital EX DTS ES - Discrete DTS ES - Matrix I know what normal DTS 5.1 and DD 5.1 do, what do these other variants do besides adding the rear center channel? My AV reciever is a full DD 6.1 and DTS 6.1 system, but I don't have the rear surround center speaker installed (no room, space behind me is a window). My question is when running a DTS ES dvd, should I use normal DTS mode, or is using ES going to give me something extra? Also what is the difference in the DTS modes? I have a bunch of DTS ES dvds, and the AV reciever defaults into the encoded mode (I think all my dvds so far are DTS ES - Discrete). Should I use what it defaults, or will it not matter much? However I have noticed I have a few DVDs that say DD EX on the back (Blade II), but they seem to default into regular DD 5.1 on my system, will switching to DD EX give me anything extra since I'm not using the center rear speaker? For anyone with a THX setup, I know THX surround is just another surround variant, but what exactly does it do when you have THX set to "on"? The THX modes my player has is THX off/on, THX surround off/on. BTW is circle surround II better than pro logic II? One thing about the rear center surround speaker, is it best to use a "center speaker" (like you have up front), or just the same speaker you have for right/left etc? Thanks for any help!