I have two B12's. I operated one for a few years, then had the opportunity to purchase the second. I have to say that just one sub moves a lot of air and in a room approximately 15'x 25' one sub is sufficient. Performance throughout the low frequencies is distinct and articulate in frequency, both on music and video. It blends so well with the other speakers, I wonder sometimes if it is actually working, as it draws no attention to its location. Yet, when it is called to hit the low note, its bliss. I've never found a 10" driver to be as fast, yet reach so low. I can find no reason to pursue more, yet I may as I like to be scared. I've been building speakers for about 30 yrs. and my next project is a pair of NHT 1259's. I hope they out preform the B12's and I'll surely be disappointed if they aren't their equal.