Designed for use with Martin Audio’s BlacklineX Series of full-range loudspeakers, the X218B is a dual-driver, high performance subwoofer with an operating range of 42Hz – 200Hz. It is capable of producing very high output levels with low distortion from its two 18-inch, 4-inch voice coil long excursion drivers. The reflex enclosure features plywood construction, a 35mm pole mount socket, integral M10 inserts, ergonomic handles, and a design that allows it to be used singly in vertical orientation or stacked horizontally.