VELODYNE ACOUSTICS HGS-12 Subwoofer High quality crossover system -- allows seamless integration with the most demanding full range speakers Switchable subsonic filter -- allows adjustment for either audio with low bass extension or dynamic home theater bass presentation -- at the flick of a switch Optional infrared remote control allows adjustment of bass output from one source to another Volume control for perfect integration with any speaker system Adjustable low-pass filter offers hook-up flexibility for all equipment