The SL 218 A is a professional active subwoofer designed to complement existing PA systems in the sub-bass range. Thanks to its integrated active electronics, adding the SL 218 A to an existing system is as easy as can be, since no extra amp racks or crossovers, etc., are needed. The SL 218 A is equipped with two direct-radiating 18" speakers in separate chambers, each powered by a state-of-the-art PWM power amplifier whose total capacity is 2.000 watts RMS. To facilitate optimal integration of the SL 218 A in an existing PA system, the unit includes gain control, phase reversal switch (0° - 180°) and a 12-dBper- octave crossover adjustable between 60 Hz and 100 Hz.