It Frees you from the constraints of having to reach the control in the back trunk where amps are usually mounted. It allows you to precisely fine tune and control the level of your subwoofer from virtually any convenient location in the car! It simply increases amplitude of the bass level at the turn of a knob as opposed to turning up the gain or sub wave boost from the amps location. Got it ?
Whether you would like to control bass levels for system demonstration; to re-set levels for audio vs. video sources; to set subwoofer levels for each recording; or to simply experiment with changes in subwoofer levels, you can do so, while giving you the ability to return to your calibrated reference level at any time.