Stereo Has no Bass

The radio unit internally on the factory system would have a channel each that sends out the different range signals. The exception is if you have a factory subwoofer - this has an amplifier and some circuitry stand alone by the subwoofer itself inside the right rear quarter trim panel in the cargo area. The only fix is to replace the unit - there are no internal serviceable components.

depends on what stereo you have in your expedition, their is the everyday stereo which you have the head-unit and 4 speakers or the Mach1 stereo. which has the main head-unit 2 amps 1 up front under the dash and the second amp which is on the sub. The stereo also comes with 4 premium 25 watt speakers with a 30 watt 8inch subwoofer. and a 6 disc changer. which 1 do you have??? I had the Mach1 till I replaced it with Pioneer/Hertz audio