I have a really lousy sub which I got free with the purchase of a center channel. It is only an 8" and I find that it bottoms out constantly if I have it at the ouput level that I want. The same deal is on now and I want to purchase a pair of bookshelves. If I had another one of these crappy subs and turned down the output of both would this help with my constant bottoming? Also, would this improve my subs extension. the specks say that it will only reach to 34 Hz will having 2 make this extension any better?