Audio Control DQ61 Equalizers and Crossovers New AudioControl OEM Processor Delivers Amazing Sound Thru Equalization and Signal Delay Designed for maximum sound quality and enhanced audio performance, the DQ-61 is the latest AudioControl processor to incorporate AccuBASS. This patent pending process automatically corrects for the bass roll-off that is common with many factory-installed audio systems Internal Channel Summing  Easy interface with factory installed amplifiers with built-in crossovers