pkafka,
I was just throwing my 2 cents worth in another thread (in the saloon) about this very topic.
Personaly, i start w/ the 990 test tones and then fianlize w/ video essential disk in the DVD player. To me, this includes the entire audio path.
I do see a difference - a couple of dbs in one or 2 channels only.
i would not be surprised one possible difference is in the quality of components in different DVD players.
i'm out of here....