Channels 1-2 and 3-4 have individual high-pass settings. The door speakers are Infinity Kappa 6 1/2 components and go down to 45Hz, giving the ability to give a little more mid bass. The kick panels have Infinity Kappa 5 1/4 components and are limited to 55Hz. I split the front RCAs from the head unit so channel 1 and 3 are left, and 2 and 4 are right.