The exact delay is not really critical at all. The whole delay thing started with Dolby pro logic which had high leakage from the front to the surrounds. The delay was needed to make the surround signal seem to more convincingly come from those speakers, and keep dialogue leakage from the center channel from being heard at the rear. With Dolby Digital and DTS, the leakage issue does not exist. The sound effects and music that is typically mixed into the surrounds is non-correlated with the signal in the front channels anyway, so delay is an non-issue.

[This message has been edited by soundhound (edited October 13, 2003).]