My Alpine components can do 30Hz but it is not the same as a subwoofer. A 6.5" speaker can only displace so much air. Even with proper sealing the speaker con't compare to a sub for bass purposes, and you can muddy up the rest of the music without enough power. My deck is 60x4 and when I was using the components for bass (before I got the Lambda) it sounded horrible. Even hooked up to my Amp it still sounded wrong.
