We can assume that the Onkyo is driving the M80s with out too much heat etc.? Crank it up and let us know how long before it shuts down if at all. \:\)

FWIW, You are also comparing against 2 different Audyssey systems, if I am remembering my Denon history.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70