Subwoofers..
two 10's or one 12? Infinite speakers.
PS. I already have the second 10, I got them for xmas last year just never got around to building the box for them. My dad had a truck box lying around so i used that.
By the way, subwoofers don't play high notes. That is why they're called subwoofers
Generally they play 20-80hz and thats it... some people only have them play 20-50hz and have midbass speakers pick up the rest. 

