Kenwood KAC-823 is a power amplifier with a variety of features that make it a great choice for car audio enthusiasts. With its low pass filter system, you can use the KAC-823 as a dedicated low output (sub woofer) power amplifier. The input sensitivity control allows you to adjust the unit according to the pre-out level of the center unit. The speaker switch lets you configure the unit for a variety of speaker impedances, and the operation switch provides a range of output options, including stereo, tri-mode, and bridged/mono.