I have all of the volumes set to max in the menu screen. I cant hear so well through the speakers. the volume is fine when the car is not moving, but as soon as you add any road noise you cant hear. I have the unit in a 07 grand cherokee with the boston sound system. I was wondering if the volume level could be affected by the harness that connects to the car. I have one of those metra chto-o1 deals and it has an adjustment to alow for the preamp voltage i think. Could my problem be as simple as cranking up the interface unit?