I know that it is fine to mix different ohm speakers, but assuming that the sensitivity level are the same and it is a straight hookup to the receiver without any adjustments, would a 4 ohm speaker play louder than a 8 ohm speaker? For example if I have Axiom M80 as my main speakers and the vp150 as my center, and just using the main volume control, would the main drown out the center?
It depends on whether the sensitivity spec was done as specified by the FCC which insists the speaker be measured with voltage the equivalent of 1 watt. By stating voltage as opposed to wattage the increase in power from a "typical" amplifier has been adjusted for impedance. If that is the case the impedance has already been taken in to account. The problem , of course, is there is no "typical" amplifier. A tube amp with multiple taps for impedance will create the same voltage/wattage into whatever load the speaker presents. It is only when taps and impedance are mismatched that power of a tube amp changes.
So would a 4ohm speaker play drowns out my 8 ohm center channel speaker, assuming everything is equal with no adjustments made? Would the sound level proportionally increase as I increase the volume? I am using a HKavr525.