The Yamaha Advanced YST II and QD-Base Subwoofer is an outstanding combination of power, depth and clarity. The QD-Bass(Quatre Dispersion) and high-efficiency amplifier delivers bass you can feel, while the BASS (Bass Action Selector System) will make both albums and movies Sound their best. When it comes to delivering rich, accurate lower bass responses for your Stereo or Home-theater system, youll find this subwoofer to be an outstanding performer.