The LSR6312SP powered subwoofer is based on a 12" woofer with JBL's patented Neodymium Differential Drive NDD™ and 250 Watts of power. An integral bass-management system provides all the features you need for today's multi-format surround production including: LCR and Direct LFE inputs, summed output for chaining multiple subwoofers, -4 dB alignment setting, and JBL's new RMC™ Room Mode Correction system. RMC Calibration Kit included.