generally caused by a amp being pushed into distorted clipping and this generates heat in the speakers voice coil ruining it eventually. just a laymans definition. they can also catch fire....
"blown speakers"
When a speaker "blows" what actually happens. I suppose its different between a tweeter and woofer, but is there some mechanical damage or is it electrical. does something break? Besides a woofer cone ripping, what happens to a tweeter if it is still working, but raspy or staticy? I have heard "blown" speakers before, or ones that didnt work at all, but I really dont know what it is that breaks and whether it is fixable or just replace.