To add bass to a factory car audio system, there is no easier or more effective way than to add a subwoofer. The subwoofer will provide the low-end punch that makes for a more complete sound, regardless of what type of music you are listening to. You can have a technician at an aftermarket retailer perform the installation, or you can wire the sub yourself and save the cost of labor.
Disconnect the negative battery cable from the vehicle's battery. The negative cable is the black cable that connects the negative lead of the car's battery to the frame of the vehicle. Use a Phillips-head screwdriver to loosen the bolt on the cable's clamp. Remove the clamp from the negative lead.
Remove the stereo from the dash. You will need to access the connections at the rear of the unit and feed the wiring kit wires through the same openings as the other wiring.
Mount the subwoofer and amplifier in the trunk of the vehicle. The amplifier can be mounted at other locations (under a seat, in the glove compartment), but the trunk offers the easiest connection to the subwoofer, as well as allowing for proper ventilation.
Connect the ring terminal from the amplifier wiring kit to the positive lead of the battery. Make sure that the fuse is removed from the terminal before connecting the power cable to the ring terminal.
Feed the power cable from the amplifier ring terminal through the firewall, under the vehicle's carpeting, to the trunk. Use a trim panel tool to remove the paneling that secures the carpeting to the floor of the vehicle. The panels can be replaced by hand.
Run the signal cable and turn-on lead from the stereo to the trunk along the opposite side of the vehicle. The power cable will distort the signal if the wires are laid at the same location.
Connect the power cable, the signal cable, and the turn-on lead to the amplifier.
Connect the subwoofer to the amplifier using speaker wire.
Reconnect the negative battery cable. Place the clamp around the negative lead. Tighten the bolt on the clamp until the clamp cannot be moved about the lead by hand.
Place the fuse into the fuse holder on the amplifier ring terminal.
