Yamaha DSR-Series takes portable active loudspeakers to the extreme limits of their potential. Designed through the application of advanced Yamaha digital and acoustic technologies perfected over several decades, DSR provides a listening experience that redefines high definition sound reinforcement. The DSR118W from Yamaha is a professional-quality active subwoofer, ideal for bass reinforcement of full-range DSR-series loudspeakers. The rugged bass-reflex cabinet houses an 18" ferrite cone woofer to provide frequencies as low as 40Hz. An internal Class-D amplifier provides 800W of output power for a strong, distortion-free performance. Parallel XLR inputs and outputs let you connect sound sources and daisy-chain multiple speakers and subwoofers. Extensive protection circuitry prevents damage from DC faults, clipping, overheating, and over voltage. The sub has a standard 35mm pole socket for mounting a speaker on top, while integrated carrying handles provide easy transport.Protection Circuitry