With an eye for system expansion, Clarion designed the DB288RUSB with 4ch/2V RCA line level outputs. This unique design assigns one pair of RCA outputs to the front channels, while the other two are assigned as a subwoofer output. The rear channels are delivered through the unit’s built-in 50W × 4-channel amplifier. You can fade front line out to the rear-speaker amplifier for overall system balance, while the subwoofer output level can be independently adjusted thanks to the non-fading volume control incorporated in the Rotary Volume Control.