Until such time as I make a decision on what brand surround receiver or receiver/amp combination to purchase eventually, for the time being I have a 2.1 ch receiver (Outlaw RR2150, 100 wpc for 2 speakers or 160 wpc for 4 speakers (A & B)). This is a pretty hefty receiver (28 lbs) and until now I've been using it only to drive 2 monitor 70s plus a powered sub.
I have just purchased 2 more m70s for a total of 4 (had to get them before they were no longer available new). I intend to run A & B speakers from my receiver using the 4 monitor 70 speakers and also a low-level sub-out jack to my subwoofer, although for the most part even with a sub I don't roll-off the mains except for a little tweak of the bass knob, since I love the upper bass quality of the monitor 70s. Outlaw states that this will be safe. However, in reality, I've heard generic recommendations that a 2.1 channel receiver should not be used for long periods or anything except low listening volumes with 4 speakers. The rationalization is that there will be dips in impedance during certain passages or types of music and HT, particular with heavy bass, which if running 4 speakers will make the individual channel impedance, already at 4 ohms, drop below 4 ohms enough to potentially stress the amp or trigger a shutdown. As my RR2150 has already been through one repair and only has 6 months left on the warranty, I want some opinions on this.
Has anyone done a serious amount of 2 channel receiver listening using four 8-ohm speakers such as the monitor 70s, and either experienced problems or not noticed any issues at all?