Hooking up a subwoofer and amplifier to a car stereo can add an extra dimension to your music. Subwoofers produce low frequency sounds that regular car speakers cannot create. To produce these sounds, subwoofers must be attached to an amplifier which acts a power source. Subwoofers must also be installed in subwoofer enclosures, which are specially designed boxes that amplify their sounds.
Disconnect the negative terminal of the car's battery, using an adjustable wrench to remove the bolt holding the negative lead onto the battery terminal. Disconnecting the battery's negative terminal will help prevent damage to your speakers and amplifier.
Attach the RCA, ground, remote and power wires to the amplifier. Each terminal on the amplifier is designed for one particular wire and will be labeled.
Attach the grounding wire to a bolt in the car's trunk. Although every car is different, there is usually a bolt connected to the metal floor under the carpet. Loosen this bolt with the wrench and attach the grounding wire. Tighten the bolt after installing the wire.
Pull the RCA, power and remote wires to the front of the passenger compartment. It is important to run the wires along the right side of the vehicle to prevent any wires from tangling with the driver's feet, or with the gas and brake pedals. There is usually enough room on the side of the rear car seat to snake the wires from the trunk to the passenger compartment. Once in the passenger compartment, the bottoms of the door sills and the plastic trim make excellent areas to run the wires.
Connect both the remote and RCA wires to the stereo unit. These wires should be placed under the dashboard to prevent them from dangling in the passenger compartment. To make the connection to the stereo unit, pull the unit out of the dash and connect the RCA wires directly to the stereo while connecting the remote wire directly to the unit's wiring harness. The wiring harness will contain a wire labeled "Remote." Simply strip the ends of both sides of the remote wire and twist the bare metal together. Apply electrical tape to seal the connections. The RCA wires can be pushed into place.
Drill a hole in the car's firewall. Make sure there are no wires or other materials in the way. This hole will be used to push the power cable through to the battery. Slide a rubber grommet over the wire, which will prevent water from entering the car, and push the wire through to the engine bay.
Cut 15 inches off the end of the power cable. Strip both ends of the short piece and the end of the long length of power cable using wire strippers. Attach a fuse box between the longer power cable and the shorter power cable. On the other end of the short piece of cable, attach a terminal ring by sliding it over the bare metal, then crimp them together. Many wire strippers have a tool that will crimp connectors. Attach this terminal ring to the battery's positive connector and reattach the power cable that was removed in the first step.
Cut two, 2-foot lengths of speaker wire from a spool of wire. Speaker wire contains two individual wires within one sheath, so be sure to strip both ends of both wires.
Attach one length of wire from the terminal cup on the inside of the subwoofer box to the terminals of the subwoofer. Ensure that the polarities of the terminals match.
Secure the subwoofer in place by putting it in the hole on the front of the box. Fasten the subwoofer using 1.5-inch screws.
Attach the second length of wire from the amplifier to the terminal cup of the subwoofer box. Again, ensure that the polarities match.
