For high-level dance music or reinforcement of bass instruments and kick drum, an HPR series subwoofer will add low-frequency extension and power to any sound system. The HPR181i single 18" subwoofer offers truly impressive low frequency extension and output. A 4" voice-coil driver and a 700 watt power module work to produce 134 dB SPL peak, at 1 meter with frequency response down to 39 Hz. The HPR181i also includes a top-mounted 35mm pole socket and heavy-duty 3" casters to facilitate load-in and load-out.