If you want your bass to be chest thumping, when the source isn't, then just turn the amp gain knob way up. Won't be accurate or true to the source mix though.
As for a "musical" sub going to only 30Hz, depends what your music is. Pipe organs go much lower. I believe the lowest note on a piano is 28Hz. A number of my music CDs contain infrasonic data, such as taiko drumming or some of my electronic albums.