How to Install a BMW E46 Subwoofer

1. Open the trunk and place your subwoofer box in position. Make sure there is adequate clearance on all sides and that the box fits when the trunk lid is closed. If you have chosen to put the box where the CD changer goes, then you may need to build a custom box, which can be easily done using fiber board or similar material.
2. Remove the subwoofer box from the trunk. Attach the speaker wire to the inside of the terminal cap on the back of the box and run it to the subwoofer. Place the subwoofer in position in the subwoofer box and secure with the screws.
3. Attach Velcro to the bottom of the subwoofer box, using wood glue. Attach corresponding strips of Velcro to the carpet in the trunk, using fabric glue.
4. Run speaker wire from the amplifier to the back of the subwoofer. Depending on where you have chosen to mount your amplifier, your wiring route may differ. You can run the wire under the edge of the carpet and trim by teasing up the edges with the screwdriver.
5. Attach the speaker wire to the terminal caps on the rear of the subwoofer box and place the subwoofer box on the strips of Velcro you installed in the trunk.