I am not sure about the model # of the Sony DVD player. I have gone thru the manual and all the settings for it. You can't select number of speakers or size of speakers using the DVD when it is connected via optical cable. You can only make sure Dolby Digital is on. I have it set to 48Khz (I think that is right). I just got the system set up about two weeks ago and was mainly focusing on getting the surround speakers right so I wasn't really focusing on dialogue (I would play scenes from movies that I knew would have surround affects and make adjustments). Now that I am happy with the fronts and surrounds I decided to actually start watching movies in their entirety. Now I have discovered this problem with hearing dialogue. One other thing, I bi-wired the Klipsh center channel and that seemed to help some...if that means anything.