Is there a problem with using together M22/VP150,QS4 and M80 in a 7.1 set up? They are all 8 Ohm speakers except for the M80 which is 4 Ohm? What setting do I set the receiver to 4 Ohm or 6 Ohm? I have the Onkyo 805. I have all except the M80 (was debating between the M60 vs M80)?

Most people have speakers that are a combination of 8, 6, or 4ohm in their systems, not a problem. Also, leave any switch to its default location, normally 8ohm, not 4 or 6? I would get some feedback from other users as Onkyo normally is not recommended for 80's by Axiom.

I think default on that receiver is 6 ohm.

Keith, yes there's no problem with using speakers of different impedance ratings in your setup. As to the impedance setting, leave it at the higher value, despite any suggestion to the contrary in the manual. Setting it to the lower value simply reduces the maximum voltage capability, and with it the maximum current and power available. Although this reduces the chance of overheating, it also reduces the maximum performance capacity and should never be used. Your 805 has a quite powerful amplifier, including output into 4 ohms, and should have no problem in the vast majority of uses.