AudioSource’s PSW8 Powered Subwoofer creates accurate bass frequencies that are important for music and home theater. The PSW8’s advanced power amplifier and special design subwoofer speaker will rock your world. Powered subwoofers have become integral to any complete audio/visual system, particularly home theater. normal speakers leave the very lowest frequencies unheard. Powered subwoofers fill in those blanks. For years, AudioSource has been the leader in providing quality powered subs at affordable prices. All AudioSource subwoofers include level controls and speaker inputs and outputs, as well as, line level inputs and outputs, a variable crossover from 40Hz to 180Hz, auto-on circuitry and a phase reverse switch.