With the JBL PRX518S 18" Self Powered Subwoofer System, you get the performance of an 18" subwoofer in a standard 15" sub enclosure. This ultra portable is a perfect addition to the PRX 500 Series and with the polarity reverse options you get even more system optimization.
The PRX518S is a self powered compact subwoofer that is made up of a JBL 2044E 18" Vented Gap Cooled woofer driven by a Crown International Class D digital power amplifier. In addition, you get a JBL proprietary DSP chip, which powers the input section giving the user selectable crossover functionality, polarity optimization, protections, dynamic limiting, and discrete component optimization.
The enclosure is designed for performers on the road and is made of quality plywood, which is coated in JBL's trademarked DuraFlex finish. The integrated pole mount gives you many mounting options especially if you're looking for a sub/satellite configuration.