Who say's you cant break your house with a subwoofer :P:P
Nah, actually thats not only because of my sub. The big crack formed after a dodgy rennovator a few decades ago put in a doorway on the other side, previous people living here in charge. He must have tried bashing the wall with a sledgehammer :p
But my 18" sub has also done some good damage to it, some of the cracks coming off the side of that like the ones on othe side of the massive one, are thanks to my sub, and my sub's also managed to make the ceiling pull away from the wall down one entire wall, half of another, and I see a new one forming down the other side too :P I see bits of crap fall down from there sometimes when I have sub loud, like over 110db.
enjoy :P