Hello Gang, Being new to the Forum, I wasn't sure if this belonged under Receivers/Separates/Amps, but I figured I'd give it a shot and share some issues with my fellow home theater hobby addicts in order to gain some insight from you guys...if you could take a couple of moments and read the lengthy post and give me some insight, I would really appreciate it...thanks in advance... I have an Onkyo TX SR600 six channel receiver at the heart of my system, feeding a Polk 5.1 bookshelf setup with a 10" powered sub. This receiver decodes Dolby Digital, DTS, Pro Logic II and even Dolby Digital EX and DTS ES six channel soundtracks; however, I do not have the sixth "back surround" channel in order to enjoy six channel DVDs such as Gladiator and Attack of the Clones...my question is, because I personally feel that DTS sounds much better than standard Dolby Digital, when I have the choice on a DVD's menu to select DTS, I do so---even when its a DTS ES soundtrack, as on Gladiator....but because I have a 5.1 speaker array, without the back surround channel(s), what is happening when I playback films with Dolby Digital EX or DTS ES 6.1 soundtracks----am I "losing" any information because I dont have that speaker? People have tried to give me all their theories on this, saying that the sixth channel is really for small ambient effects, and have also told me that if I have my receiver set to acknowledge that there is NO back surround speaker in the setup menu, the receiver will automatically "matrix" the back surround information into the two rear surrounds----is this true? They say it will cause a kind of "phantom" or "ghost" center image if I sit EXACTLY BETWEEN the two rear surrounds; is this so? Is my receiver "matrixing" that sixth channel's sound into the rear surrounds when playing back 6.1 channel DVDs? And on the topic of decoding properties, what are all the differences here and am I missing something by not having THX certified gear? I understand Dolby Digital, being a standard 5.1 system, and DTS, being another 5.1 system (but sounding better in my opinion---much louder and precise in effects placement)...but then there is DTS ES, which expands to six discrete channels, right? And so what is the difference between DTS ES and Dolby Digital EX? Are they just competing formats doing the same thing? My Gladiator DVD offers a DTS ES soundtrack on the menu; my Exorcist and Episode II:Attack of the Clones DVDs both offer Dolby Digital EX soundtracks...the remainder of my DVD collection contains movies that only have normal Dolby Digital 5.1 or normal DTS...but my Onkyo decodes only standard Dolby Digital, DTS, DTS ES, DD EX...it is not THX certified or some such rhetoric; am I missing something with this receiver I have----even if its only connected in a studio apartment with a small listening space? Now, I have heard it all about calibration and getting an SPL meter/disc and all that---fact of the matter is, my speaker system is calibrated based on the values an ex-co worker surround-phile of mine punched into the receiver when he first set the system up for me, and it sounded PERFECT in my opinion---he had it set up so that the two fronts and two rear surrounds are all at "+6" on the calibration, and the center and sub are bumped up a bit higher at "+8"; it seems everything sounds about right at these levels. Still, even with the Onkyo "INTELLI VOLUME" system set for all components at "+12" (maximum) (this is a system which allows you to set individual volume gains for each piece of equipment plugged into the receiver----I have it set to "+12" for all gear so that each component is getting full volume output through the receiver) it still seems like on many DVD soundtracks---especially Dolby Digital selections---I need to crank the volume up to at least 45 to 55, maybe even higher, in order to get "significant" sound levels out of this receiver. This SR600 is rated at 80 watts x 6, but I need to crank the volume up to pretty high numbers in order to get the DVD soundtracks---or even stereo music---really crankin'... Now, I have heard countless theories on this, as well...that it is normal for Dolby Digital DVDs to sound weaker compared to others, and that the dialogue is always softer than the effects or music...and I have read many, many reviews of this receiver on the Internet, and all owners have said the same thing about this model..."useless volume below 40..." "why did Onkyo even bother putting a volume control on this thing below 50?"....the reviews are endless on this problem...is this normal for an 80 watt per channel receiver---that is, needing to bring the volume up pretty high in order to get satisfactory listening levels? I have been told not to look at the number value on the screen when raising or lowering the volume because these are digital volume steps, unlike old stereo receivers which were analog in volume control, and you were able to tell when you were literally "halfway up"...I was told with these new digital surround receivers, there is no such thing as "halfway up" really, and I shouldnt really look at where the volume number is....is this normal?