REF1600A 600-Watt mono subwoofer amplifier with on-board electronic crossover and variable bass boost circuit. The Reference 1600a features a 12dB per octave electronic crossover, allowing you to optimize bass performance based on enclosure type and subwoofer selection. Full-range preamp outputs faciliate use of multiple amplifiers without the need for noisy and expensive adapters or signal splitters. Remote level bass control included Port for future expansion products provided.