Hi Rick and all,
As I explained in a PM to Rick, impedance ratings by the designer are "nominal"--arrived at by eyeballing the overall impedance curve and picking a number that is kind of an average. Since the M80 impedance curve does touch 4 ohms at several places, and remains below 8 ohms up to nearly 1 kHz, for the sake of clarity, Axiom refers to the M8os as "4-ohm speakers". Actually, Ian Colquhoun, the M80s designer says they are closer to 5 ohms.
The point is that in the frequency range where the greatest amount of current is drawn, the M80s' impedance is at 4 ohms or slightly above that figure, so that's why we give it a nominal impedance rating of 5 ohms. To avoid confusion in the specs we call it 4 ohms.
Regards,
Alan
