The 4 ohm Axioms won't hurt the sound, it'll just put the receiver at risk; and as Mojo said, that receiver should go into protection if you're driving it too hard (e.g., loud).
I don't think the frequency response is the problem, because center channel complaints usually occur above 20-40 Hz that the JVC lacks. The THD doesn't bother me too much either. I think the problem is the lack of a calibration feature on the receiver.
TerryD, you might consider getting a receiver that can be tuned; almost all of them have that now. (I'd look at Yamaha, Denon, or Marantz).
