The GP600 from Crunch is a 6.5 inch active enclosure subwoofer with an integrated Class A/B Amplifier. The device features an adjustable low-pass filter in a range of 50 to 150 Hz as well as a bass boost of 0 to 12 dB. Additional technical features include a phase switch with 0/180 degrees, RCA inputs, and high-level inputs. An automatic ...