the playback level in my cd collection varies by as much as 30 dB.

it seems that the standard levels in movies is not adhered to all the time by the movie studios; there are differences in levels there too, but much less than with cd's.
right now, i can't tell by how many dB's it varies as i'm in the process of updating my system and individual movie levels are not calibrated.

See: http://www.blu-ray.com/community/gallery.php?member=Gelli
or: Axiom Gallery