The SUB 8004-AS is one of the most powerful 18-inch subwoofers in professional sound reinforcement technology. Its hyperventilated 18-inch high-performance woofer with a 4.5-inch voice coil wound inside and outside provides a powerful bass foundation. With a 1250-watt digital amplifier module, the SUB 8004-AS is equipped for the most demanding tasks. The input control panel includes volume control as well as switches for "Deep/Punch," high-pass filter, phase, cardioid preset, and delay.