The SX118 is a compact, high performance subwoofer that extends the low frequency operating range of the system to 47Hz and provides exceptional low frequency output for such a compact enclosure. An ideal partner for the WPM, it features a long-excursion 18-inch (460mm)/4-inch (100mm) voice coil driver with a water-resistant cone and triple roll surround in a compact reflex enclosure. The design of the 18-inch driver maximizes output while minimizing power compression and distortion, and the four reflex ports have a large frontal area to reduce turbulent air noise at very high levels. The enclosure is constructed from multi-laminate birch ply, finished with a durable textured coating and equipped with a steel grille, twin grab handles, skids, flying inserts for installation and a threaded pole socket for pole-mounting up to 4 WPM enclosures as a simple plug-and-play system.