A speaker box is designed to hold a subwoofer to create a large amount of bass within a car. These speaker boxes, or subwoofer boxes, are typically made of medium-density fiberboard and come in various sizes and shapes. Each subwoofer requires a particularly sized box to create a maximum level of bass. Speaker boxes must have a correct interior volume and must be able to hold the subwoofer firmly in place. Building a speaker box is a simple task and should take less than two hours, plus time for drying.
Determine the dimensions of the speaker box. The 12 Volt, a car audio website (see Resources), makes it easy to calculate subwoofer box dimensions. This calculator is web-based and allows you to input information about the subwoofer diameter, depth, and the recommended interior volume of the subwoofer box. These three measurements are detailed in the manufacturer's manual of the subwoofer.
Cut the six sides of the subwoofer box using measurements from the subwoofer enclosure calculator along with the subwoofer hole and terminal cup hole. As each side is cut, make sure to label them to prevent confusion about where they belong. Cut the hole for the subwoofer by placing a compass in the middle of the front panel, drawing a circle equivalent to the diameter of your subwoofer using a compass, and removing the hole with a jigsaw. Cut the hole for the terminal cup by tracing an outline onto the middle of the back piece and cutting this piece out with a jigsaw.
Attach all six sides of the subwoofer box together. To securely fasten the panels in place, pre-drill three holes along each seam and apply carpenter's glue. Use three 2-inch screws to securely fasten the panels in place. Also, attach the terminal cup to the back panel. The terminal cup will come with screws to fasten it into place.
Seal the box using silicone caulking. Create a bead of this caulking along every interior seam and allow to dry for at least 24 hours to prevent the fumes from damaging the subwoofer.