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.
I known I can hear the difference almost immediately, but like any audio differentiation I think it takes a certain amount of "training" of the ear. I doubt most people would notice a big difference initially, but after listening to great BD lossless tracks for a while and I'm sure they would begin to notice.
I think the primary differentiator is that it takes more work/skill to mix an outstanding lossy track than to mix a great sounding lossless track. In mixing both you need to be aware of spatial positioning and depth of the track, but with lossy tracks you need to also be very aware of dynamic range, compression artifacts, etc... all the standard issues linked with lossy compression. There's simply more to get right and consequently more that can go wrong.
I've heard both great lossy and lousy lossless mixes. But, I'm willing to bet that as a percentage per track type, there are more great sounding lossless mixes than lossy ones.
Lossless audio allows the sound engineer to focus on the soundscape and ambience, and forget about the technical challenges associated with lossy compression.
All that being said, I don't know why studios don't just go LPCM everywhere? Why even bother with DTS-HD MA or TrueHD? Same end results and with the storage capacity of BD it's not like space is an issue...
