As Otto says, you can scroll through the Dolby or DTS modes with the Dolby and DTS buttons ("Dolby Digital" will be an option at some point for DD tracks and will apply no extra processing, same with "DTS"). Keep in mind that the 990 will remember separate settings for each input for each input format - including separate settings for Dolby 2.0 and Dolby 5.1 (so you could use PLII/IIx with Dolby 2.0 without doing so on Dolby 5.1). I haven't tried any DTS 96/24 stuff since I don't know of any such discs in my collection.