The PB4000 Subwoofer is a powerful high-end reference subwoofer for home listening. Its 13.5" high-excursion SVS driver lets its frequency response extend as low as 18 Hz & delivering higher output levels than usually seen from subwoofers of this size. The PB4000s amplifier provides 1200 watts of RMS power from a Sledge STA-1200D DSP amplifier with a MOSFET output stage. All rounded out with a triple-ported cabinet that increases low-frequency response subwoofer is clear powerful & articulate offering low-end support like no other.