It is relatively simple, with a few carpentry tools and supplies, to build your own speaker box to fit in your vehicle. There are a few things to take into consideration before starting such as the space available inside the vehicle (this will determine the size of the speaker you will want to install) and your budget. The most effective building material is 3/4” high density particle board. This is what most speaker box retailers use when constructing standard speaker boxes.
You will need some simple carpentry tools such as a tape measure, power drill, a large drill bit, jigsaw or router, file, sandpaper, spray glue and silicone wood glue or sealer. You will also need carpet for the exterior of the box, screws, speaker connectors, which are available at most car stereo shops, and the speakers. You can consult your local speaker or car stereo retailer for their best recommendation of the size speaker to fit your application. If you have a small vehicle, the largest speakers will probably not be your best choice. The retailer you purchased the speakers through will be able to tell you the size of the enclosure you need to make, also.
With your tape measure and a pencil, trace out the pattern for your speaker boxes on the particle board. Remember, you are cutting out six sides to construct the entire enclosure, plus a divider if the enclosure is meant to hold two speakers. Once the jigsaw is used to cut out all the sides, trace out the size of the opening on the face of the enclosure for the speakers. Using the power drill, drill a hole at the edge of the circle you traced out for the speaker. This will be the pilot hole for the jigsaw you will be using to cut out the opening of the speaker. If you have a router with a 3/4″ bit, you will not need to use the pilot hole. Use sandpaper and wood file to smooth the edges of the hole(s). You will need to use the same process to cut a 2” hole on each side of the box. These holes will accept the speaker connectors. The edge of the speaker, the cage with the screw holes, should rest on the particle board just outside the edge of the holes.
Using the silicone wood glue or sealer, squeeze a line around the edge of all the joints of the enclosure. Using wood screws join the edges of all the sides of the box, including the face. The silicone will make the enclosure airtight so the speakers work to best effect. Spray glue, sprayed on the outside of the box and the back of the carpet, seals the carpet to the outside of the box. There should be some overlap over the opening for the speaker. Using a razor or Exacto knife, slice the carpet around the edge of the speaker hole and fold the carpet into the speaker box. Speaker wires connect from the terminals on the speakers to the corresponding terminals on the speaker connectors.
Insert the speakers into the openings and screw the edges down using the factory screw holes around the edge of the speaker and wood screws. The speaker box should now be ready to install into your vehicle and connected to the car stereo. Using the manufacturers instructions, make the appropriate connections and enjoy your new full bodied music experience. If you have any questions during your building process, your local car stereo retailer will usually be willing to provide you some direction through the process. A well built speaker enclosure will provide years of musical enjoyment.