I have a similar setup (m60's, vp150, etc) driven by a low-end Kenwood (5 x 100 watts). I don't yet have a sub. I just received my axioms this past weekend and had some problems with 'clipping'. At one point the receiver shut itself completely off after I had increased the volume. I asked Axiom tech support about this, and here's the reply:
"I'm delighted you like you M60s and VP150.
Keep in mind that the so-called "100 watts per channel" rating of your low-end Kenwood is measured with one channel driven and the other five channels at 1/8th power output. I know, it's very misleading, but the standards for power output ratings were seriously diluted to enable receiver manufacturers to build 5.1 channel receivers and sell them cheap. Most of these models only deliver 30 or 40 watts per channel when all five channels are driven simultaneously.
You are simply driving the Kenwood into clipping because the M60s are capable of very clean deep bass output and demand more power than you Kenwood will supply and because you are not using a sub. Bass demands most of the power from a receiver, and because you are not using a subwoofer with its own built-in amplifier, your Kenwood has to work too hard, so its protection circuitry shuts it down.
It should be okay when you add a sub and set all the front speakers to "Small". Then the Kenwood won't have to work as hard.
You could also consider upgrading to a more powerful receiver with a better power supply: I recommend Harman/Kardon, Denon, and the new NAD models. I'm using an H/K 525, which will even drive our 4-ohm M80s. The newer model is the H/K630 or the 7200 (the latter is massive)."
Axiom also assured me that my 8 ohm receiver wouldn't have a problem with their 4 ohm products. I am going to add the sub next, which I am sure will help, and also looking at Denon recievers (1804 is catching my eye). Hopefully you will be fine with your sub already in place.
