I am setting up a 7.1.4 system with a Denon X3700. Speakers are Revel in walls all around (W990s, C/W530s) so 8 ohm and solid sensitivity. Subs will be crossed over around 80 Hz. I need a 2 channel amp to drive the full 11 speakers as the AVR only has 9 built in amps and was debating 2...