I'm not 100% sure but, I believe the preferred setting on the receiver would be 0 and the sub turned up to what you need it to be. If you have to turn the sub above 1/2 then you would want to turn the receiver up a little until and turn the sub back down. That way you will be able to adjust the sub up or down from the receiver +/- whatever your source material needs. But in all reality, it probably doesn't matter.

Denon 5803 Denon 3910 Axiom M80ti's, QS8's VP150, EP500's (7.2)