If you want good slam with a fairly cheap speaker see if you can find a pair of Sony SS M9's. There US designed and made, and the Sony label will let you buy them cheap. They cost around $6000 but I've seen 'em for as little as $1000, and they will rock, or jazz, or whatever you want 'em to do.
...an' dats da name a dat tune!
...an' dats da name a dat tune!