A properly built car audio subwoofer box will disguise your subwoofer, protecting your audio system from theft and damage, while providing the pounding bass you want in your car's sound system. Follow these tips below to build a subwoofer box.
Step 1 - Measure the Available Space for the Subwoofer Box
Choose a location inside your vehicle behind the back row of seats for the subwoofer. Measure the space from the middle of the seat to the floor and across the back of the seat. Make sure you have at least 10 inches between the seat back and the rear hatch of the vehicle.
Step 2 - Choose your Subwoofer Size
For a mid-sized car, a 10-inch subwoofer will fit well. For a large SUV, go up to 15 inches for the subwoofer. Most subwoofers are six inches deep from front to back, with the case two inches larger in width and height than the subwoofer dish.
Step 3 - Purchase Your Supplies
Buy a sheet of 8X8 medium density fiberboard (MDF). Have the building supply company cut it in quarters, so you have four sheets of 4X4, for easier transporting. Get all the other supplies you need at the same time. You will need a carpet remnant close to the color of your interior upholstery. It should be large enough to cover three sides and the top of the subwoofer box.
Step 4 - Measure and Cut the Box Sides and Top
Measure your subwoofer and add two inches to its depth for the box depth. Add one inch to each side for the width, and match the height of the box to the subwoofer case's height. Cut your MDF sheets to the dimensions you need.
Step 5 - Cut Out the Front Panel for the Subwoofer Dish
Measure the inner rim of the subwoofer dish. Cut a hole slightly smaller than this diameter in the center of the front panel of your subwoofer box. This panel will face the front of your vehicle near the back seat, so it won't be visible from outside.
Step 6 - Assemble and Caulk the Box
Screw the box together with the wood screws. Don't put the lid on yet. Place the subwoofer in the middle of the box from front to back to test the fit. Draw a hole on the front panel of the box, to be drilled later for the wires. Remove the subwoofer and caulk the box. Drill the hole for the subwoofer wires.
Step 7 - Seal the Subwoofer Inside the Box
Put the subwoofer back in the box and pull the wires through the front panel hole. Screw the lid onto the box, and caulk around the edges. Attach the top of the box to the subwoofer case with four screws, one at each corner.
Step 8 - Cover the Subwoofer Box
Cut the carpeting to size. Spray-glue each box panel and press the carpet down firmly onto the box.