Alpine R-A90S R-Series 6/5/4/3 Channel Power Amplifier with staggered power - The R-A90S features a staggered power channel layout that allows each channel to host different levels of power, compared to traditional, multi-channel amplifiers. This allows the R-A90S to effectively function as both a 3-way active amplifier and a 5-channel amplifier by delivering the power you need to the channels where you need it the most. Technical Specifications - • Hi-Resolution Audio Compliant (40k Hz) • CTA-2006 • Alpine’s Class D Amplifier Circuit • 75W x 4 + 150W x 2 (4Ω, 14.4V, Less Than 1% THD +N) • 100W x 4 + 250W x 2 (2Ω, 14.4V, Less Than 1% THD +N) • Bridged: 200W x 2 + 500W x 1 (4Ω, 14.4V, Less Than 1% THD +N) • S/N Greater Than 85dB (ref. 1W into 4Ω) • THD + N Less Than 0.03% (ref. 10W into 4Ω) • Frequency response: 10-45kHz (0/-3dB) • Damping factor Greater Than 500 Alpine RUX-KNOB.2 Remote Bass Knob