Thanks, John, that helps me get a bit clearer on the subject. I don't remember where we left the settings of the 6004 last time, but we'll have more time to play with it today and we'll run Audyssey and see where it sets the mains relative to the center and surrounds.

The center is the B&W HMT7, if I recall correctly, and it should have a sensitivity of 91dB. I'm not sure of that of the mains, but it's definitely lower than that. So that explains at least part of the difference in volume.