Axiom Home Page Forums General Discussion Technical Questions Multiple speaker lines into 1 speaker?

I wouldn't do this even if you were sure that both amps would never be active at the same time. It seems pretty likely that the powered-off amp would present enough of a load that it would impact the sound.

Can you switch at line level instead, eg. run a line level cable from the pre-out (or something) of one amp to an aux in on the other amp and always use the same amp to drive the 40s ?

Alternatively, get a cheap switching box.