Subwoofers with LFE output

RCA (LFE)

— an output that provides a "bass" audio signal — only at those frequencies at which the subwoofer operates. Allows you to connect to the system a second active subwoofer (or passive with its own amplifier); models with a similar output will be especially useful in cases where you want to have an additional subwoofer, but there are not enough inputs in the player or receiver for this.