The bassRESTOR is a fantastic & fun product. Many recordings simply do not have very much bass in them. Whether it is classic rock, banda, metal, older recordings, compressed audio.... the musical information simply is not there. The bassRESTOR can put that bass information back into the music! The control knob for the bassRESTOR has a subwoofer level, as well as a RESTOR effect dial, so you can control how much processing is done. This can be used with factory, or aftermarket head units. This also will deliver a high voltage, quality signal to your amplifier.