Designed to complement any full-range PA loudspeaker and a perfect companion for the PreSonus® ULT12 and ULT15, the ULT18 subwoofer delivers a powerful, clear, and accurate low-end punch. With 2,000 watts (peak) of Class D power and a direct radiating, ported enclosure, it has all the muscle needed for the detailed low-frequency performance audio pros demand. Its custom 18-inch low-frequency transducer with 4-inch voice coil provides 7 mm of driver travel before over-excursion to push more air and bring more thump. To provide maximum versatility, the ULT18 offers several important user controls. Unlike most subwoofers in this class, the ULT18 features a variable lowpass filter that enables you to accurately dial in the crossover transition between the subwoofer and your full-range system. Two DSP presets provide extended low-frequency performance or a more natural response to suit a variety of applications, and of course you get polarity reverse. A Mono Mode function is also provided to simplify cabling multiple mono subs in a stereo system.