Anyone have an answer to this? My 5th (!!!!) midrange just blew. I do have a cheap receiver (Denon AVR-S540BT); would that be the reason?
Considering that you've spent probably as much on replacement midrange drivers as you did on the receiver, I would say it's time to upgrade the receiver. You need good clean power to drive these speakers effectively. Also, I would disable any sort of EQ or tone adjustments in the receiver. I have set up two pairs of M60s on four different receivers and each time the speakers are happiest with absolutely no adjustments to the EQ at all. In fact, each time, the auto EQ settings that resulted from running the room correction/room setup on the receiver absolutely wrecked the sound quality. Everything else from the auto setup was great, just not the EQ. So if you've done that, and are running a cheap/low power receiver I can see maybe having problems with midranges. Though I might also consider sending your crossovers to Axiom or another well regarded professional to have them gone over to make sure something hasn't popped.
Another thing to check would be your source(s). When I play Pandora through a Roku it sounds quite distorted and would likely blow drivers if I let it play loudly for a long time. (I don't do it at all)
Lastly, this is usually not a problem with modern/simple setups, but you should always turn on all of your sources first before turning on the receiver to avoid the thump/pop/crack that you can sometimes get by doing things in the wrong order. Likewise when powering down, go in the reverse order, receiver off first then everything else off.
Hope you get your issue resolved.
