Yamaha YST-SW1500 12" Powered Flagship Subwoofer (Black) (Discontinued by Manufacturer) Built-in 1,000-watt amplifier delivers efficient power 12-inch long stroke with dual bias cone driver YST Active Servo Technology for expanded base response 16 to 200 Hz frequency response, plus line level and speaker level inputs Measures 16-1/2 by 20-1/8 by 17-3/4 inches (width by height by depth)