Not all audio on all discs are equal, it just depends on how they are mixed. Both are compressed lossless formats, and should sound exactly the same if encoded in either format. If you are playing a disc with PCM audio and your receiver displays PCM, then you are getting the best audio you can get. Not sure about your receiver settings, have you looked at the batpig denon to english instructions, if not check it out, it may assist you in setting up your receiver properly. I have a 1910, but don't use it for blu ray or HD material, only SD stuff, and mainly just for stereo audio so I can't help you with that stuff.