DESC: The PRX518 is a high performance self-powered compact sub-woofer system. The PRX518S is comprised of a 2044E 460 mm (18") VGC (Vented Gap Cooled) woofer driven by a Crown International Class-D digital power amplifier. A propriety digital processing chip (DSP) chip is at the core of a fully featured input section, providing user selectable crossover functionality, polarity optimization, protection, dynamic limiting and discrete component optimization.