Phoenix Gold SD 600.1 Mono-block 600 Watt Amplifier Power 14.4Vdc  1% THD - 200 x 1 @ 4 ohm - 400 x 1 @ 2 ohm - 600 x 1 @ 1 ohm Typical Efficiency: 70% Low Pass Crossover Range: 30Hz to 300Hz Subsonic Crossover Range: 10Hz to 55Hz