The more recent models of Denon, and presumably Marantz as well, is using about 72-73 dB, whereas the older models, such as HD's 4520 (I had the AV8801, same year (more or less) model as the 4520) would be about 74-75 dB, that's based on my Umik-1 and REW, not just the RS spl meter.
With Anthem ARC Genesis, I have to wear earplug every time and hope my smaller surround back/height speakers don't blow, so you can fill in the blank...