So what I'm assuming is that the mix of my speakers 4ohm and 8ohm is alright to do, you don't have to have them at all the same ohm ratings.

M80 Fronts 4ohm
Energy Center 8ohm
M22 Surround 8ohm

They sound great even at -9db (cranked), I thought they would be louder at lower volumes, is there a way to make them louder at lower levels? More amp power maybe? or is -30db going to be the same loudness no matter the amp or speaker?

Thanks !