JL Audio HD Series HD900/5 5-channel car amplifier
Class D amplifier design. variable high-pass filter on front and rear channels (50-500 Hz, 12 or 24dB/octave). variable low-pass filter on subwoofer channel (50-500 Hz, 12 or 24dB/octave). subsonic filter on sub channel (24 dB/oct at 30 Hz).