To echo Chris's comments on variability in levels, it's true. The live in HD broadcasts from the Metropolitan Opera in New York are remarkably (and annoyingly) low in level, perhaps to allow for exremely loud crescendoes and the full dynamic range with full orchestra and chorus. I find I have to run my AV receiver as loud as -10 dB.
Those broadcasts are mixed in Dolby Digital 5.1 from a remote truck parked behind Lincoln Center. When I've walked past the remote truck I've sometimes thought of knocking on the door and saying, hey, get those levels up a bit!!
On CDs, I've found variations of 15 to 20 dB from one low-level disc to some "hot" ones.
Regards,
Alan
