I'm debating the purchase of a M22/VP100/QS8 set to be driven by a soon-to-arrive Panny XR50 digital receiver, which is known to have trouble with low impedence speakers. How low does the QS9 dip? Have there been any measurements made/posted anywhere?

Ep, welcome. No QS8 impedance measurements beyond the nominal 6 ohms have been published as far as I know. Of course, it's entirely possible to dip to 4 ohms at one or two points, but you might contact Axiom directly to see if more specific information or advice on the point is available. I'm not familiar with the XR50, but I note that receiver difficulty with impedance is sometimes exaggerated on audio forums.

Thanks for the welcome and reply. When it comes time to order the speakers, I'll pose the question to Axiom directly.

I have a feeling it'll be ok; I read here that even the 4 ohms nominal M60 only goes down to 3.5. Such dips should be acceptable, according to the guys who've played with the reciever.