The Planet Audio EC20B three-way electronic crossover is a high-fidelity signal processor that allows you to customize the low level output of your input source (a car radio), so that the signal can be applied to an amplifier or amplifiers as a part of a two-way or three-way mobile audio system. It is intended for use in a car audio system which includes amplifiers in the signal path after the crossover, and provides front, rear, and subwoofer low level outputs via RCA connectors.

The EC20B is optimized for head units which provide outputs for Front (UR), Rear (UR), and Subwoofer (UR) channels. But what if your head unit only provides a single pair of stereo (UR) outputs? By setting the Parallel Input selector control to Out, the signal applied to the Front (UR) EC20B inputs will also be routed to the Rear channel. This eliminates the need for external Y-adaptors, which can sometimes add noise to the system. Now you can provide custom processing to the Rear channel independent of the settings you apply to the front.