How to Build a 12 inch Subwoofer Boxby Nichole Liandi ; Updated September 28, 2017
Items you will need
Two 4 by 8 foot 3/4-inch MDF (medium density fiberboard) boards
Circular or table saw
Ruler or tape measure
Drill with 1/8-inch drill bit
Speaker terminal cup
Twelve-inch subwoofers are one of the most popular sizes used in car-audio applications. They can produce a lot of bass yet aren't so big that they can't fit into most vehicles. It's important that a subwoofer be mounted into a solidly constructed sub box if you want to get the best possible sound from it.
Cut two MDF panels measuring 18 by 18 inches with a circular saw or table saw. These will be the front and rear panels of the subwoofer box.
Cut two MDF panels measuring 18 by 12 inches with a circular saw or table saw. These will be the side panels of the subwoofer box.
Cut two MDF panels measuring 16 1/2 by 12 inches with a circular saw or table saw. These will be the top and bottom panels of the subwoofer box.
Place the top, bottom and side panels together to form a hollow square with equal dimensions (18 inches) around the perimeter. Do this by overlapping the edges of the top and bottom panels with the side panels. Screw the pieces together with 1 1/2 inch wood screws spaced every 3-4 inches. To make it easier to put the screws in, make a pilot hole with a drill and 1/8-inch bit for each screw.
Using your 12-inch subwoofer as a template, cut an opening in the front panel with a jig saw and mount the subwoofer into the opening with woodscrews.
Using a speaker terminal cup as a template, cut an opening in the back panel with a jig saw and mount the terminal cup into the opening with woodscrews.
Mount the front panel with the subwoofer onto the hollow box you created in Step 4. Secure the panel to the box with woodscrews, using the same spacing and method as described in Step 4.
Connect a 20-inch long piece of speaker wire between the terminals of the subwoofer and the back terminals of the speaker terminal cup.
Mount the back panel onto the box using the method described in Step 4.