I actually "blew" one of my speakers in my 4x12 the other day! I was messin around with the clean channel on my Triple X head and turned the master volume up all the way and then the channel volume up about half way and got a cool crunch, so I turned it up to about 3 o'clock and got a sweet AC/DC type tone for about 10 seconds before BAM! I hear a pop and then the top left speaker is rattling very bad. So, I take the speaker out, and if I shake it, I can hear something ratteling inside it. What did I do to the speaker (technically speaking)? It was an Eminence Governor btw. Because of this, I took the rest of the speakers out, and put the G12T-75's back in, and then put one of the Gov's and Wizards in my classic 50. The combo sounds great with that amp. It's not boxy anymore and it really opened it up.