I was cranking beethoven when I blew a midrange on my 3.7s. I also may have clipped as these are a pretty difficult load. It happened in my first couple of months with them and no problems since. I doubled the amp and run bridged mono now. 6-800 watts into 4 ohms. I'm also more careful with the volume. They play plenty loud but I will say that they were not distorting audibly when this happened so it may be that they don't give much warning before failing.
The store I bought them from said one thing that can happen is the glue between the woofer cabinet and top can dry up and fall out meaning that the air pressure in the woofer cabinet can leak into the top chamber and put pressure on the mid/tweeter. You can push on the woofer and radiator (gently, obviously) and see if the mid moves at all. If it does you have a leak that needs to be plugged. Open up the top and seal up anything that might be leaking from the woofer chamber with wood glue or caulk or something.
The store I bought them from said one thing that can happen is the glue between the woofer cabinet and top can dry up and fall out meaning that the air pressure in the woofer cabinet can leak into the top chamber and put pressure on the mid/tweeter. You can push on the woofer and radiator (gently, obviously) and see if the mid moves at all. If it does you have a leak that needs to be plugged. Open up the top and seal up anything that might be leaking from the woofer chamber with wood glue or caulk or something.