The MS-WBC is a radio-frequency (RF) wireless control that provides precise adjustment of bass levels for one or more JBL® MS Series car audio amplifiers. The product’s genius is not just that it’s wireless; it’s in the way that it accomplishes its bass-boost mission. Other bass-boost circuits increase the effective low-pass crossover frequency as bass is boosted, because the slope (roll-off or “Q”) is constant. In the WBC circuit, bass boost is shelved to maintain a linear boost to all frequencies below 60Hz, up to +10 decibels of increase. The low-pass crossover frequency is constant because the Q of the filter is adaptive based on boost levels. It’s a critical step of precision to ensure that bass is realistic and blended, not overpowering or misplaced because of varying low-pass crossover points. An onboard 3-volt CR2025 battery provides the unit’s power, but the unit also has an optional, hard-wired plug for connection to your car’s electrical system. This is the way all bass-boost controllers should be: easy to install and precise in adjustment.