i have a question about 8ohm speakers. when setting the gains on the amp to these speakers, would you set to the speaker or amp? what i mean is, say you have 120rms 8ohm speakers and 120 x 2 @ 4ohm. would you set your gains to 120 x 8 (sqrt) = 30.9v or 120 x 2 (sqrt) = 21.9v ??