I also agree it is your room, time for some bass traps/room treatments.

Also ensure you use multiple, at least 4, preferably 6 or the full 8, positions for Audyssey to take it's readings from.

I would say that 40hz is too low for the M22, although I did like mine when run 'full range'(I had a very poor sub at the time), but you can easily adjust the M22 crossover point up to a more natural 80 in the Denon's menu.

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