Addon Sub adds another dimension to all music and movies. The powerful bass creates a physical experience not only inside your ear, but inside your body, and gives you an added dimension to the listening experience. It can be connected to any amplifier or receiver, as well as connected to Audio Pro speakers. The 8" downfiring woofer is powered by a 150 W class D digital amplifier with frequency range 35 - 130 Hz. It has variable crossover and you can shift phase for easier placement and adjustment to your room.