You will hear about two different categories of subwoofers: (1)sound quality and (2)spl- sound pressure level for booming bass. The top of the line subs are good at both.
I have always put JL Audio at the top of the list, but if you want you are looking for more sound quality then check out Focal, Infinity, or Alpine. If you want looud booming bass then look into Rockford Fosgate, Kicker, RE Audio, MTX, JBL, Polk Audio, and Kenwood.
