Alpine MRP-F450 4/3/2 Channel Power Amplifier RMS Power (at 14.4V THD+N, 20Hz-20kHz) Per channel into 4 ohms: 70W x 4 (0.08% THD) Per channel into 2 ohms: 140W x 4 Brigded 4 ohms: 350W x 2 (0.3% THD)