I've had a pair of M3s for a week and have been noticing a slight buzzing or vibration in one of them, usually on acoustic-bass or low-bass notes, but also once on a strong acoustic guitar chord.

They are stereo-only speakers, "B" speakers off a Sony STR-DA4ES. Has anyone seen ... I mean heard this before?

call Axiom service an d support. you probably have something loose in there. have you tried slightly tightening the screws around the tweeter and woofer to see if that helps?

Yeah I sort of thought there might be a screw loose somewhere

Probably call Axiom tomorrow for some guidance.

I've been accused of that here too-but not concerning the speakers,(I've had Three M3s for a number of years) but I digress....

I had the same problem with my 22s. ry to isolate what speaker & what driver the buzz comes from, then remove that driver. I'm willing to bet you that you've got a wire that's touching the driver basket and is vibrating at low frequencies. That's what was wrong with mine.

I had the same problem with a wire, inside the speaker, vibrating in my left M60. Thanks to Joe's guidance, all I had to do was take the rear panel with the binding posts off, pull out the crossover, and try to gently move the wire a bit. I moved it enough were the vibration is only audible (barely) while playing at much higher levels than I usually do, and only when I put my ear directly behind the speaker.

If it's not a loose screw on the speaker, it's most likely a wire inside vibrating on the cabinet.