As Chris mentioned, the audio difference between the loss-less formats and the improved lossy DD and DTS content has been shown in blind testing to be nearly indistinguishable, so don't expect to hear a significant difference unless the particular disc wasn't processed equally well.
In all fairness John, I recall reading results of a blind listening test or two where the listeners could tell a difference, and the nod was given to the high rez tracks.
I know that in my set up, I can tell whenever the BR disk is playing the standard sound track. When I switch over to the high res track, the difference is beyond doubt. Enough so that I can’t help but wonder what folks are smoking when they make claims to the contrary.
Now all that being said, I have numerous BR disks with downright horrible High Rez sound tracks. Just because the BR has DD-HD or DST-HD on the cover, that does not guaranty high quality audio.
