Put some extra thump in your Chevy Silverado by installing a subwoofer behind or between the front seats. You can mount the speaker permanently or you can have one that can be removed to make your truck the center of attention at your next tailgate or party. With a removable box you can pull it out onto the bed when the weather is nice and you're tailgating, avoiding having to leave car doors open.
Measure the space behind the seats where you plan to mount the box. Then measure the depth and diameter of the subwoofer. The box should be at least 2 inches deeper than the subwoofer and allow enough space for the subwoofer to be mounted on the front but still fit within the space you measured behind the seats. The space you have available varies widely between models.
Calculate the internal dimensions of the box by subtracting two times the width of the board you're using from each dimension and then multiplying length by width by height. If you're using the recommended 3/4-inch MDF then you would subtract 1 1/2 inches from each dimension (3/4 x 2). Compare this measurement to the recommended box size for your subwoofer. Adjust the dimensions as needed to make the box fit within the specifications and the space.
Connect the speaker wire to the back of your head unit or amplifier. Run it down inside the dash and along the center console until it comes out approximately where you want it in the back seat. In most Silverado models the dash will pop off enough for you to get the wire inside, as will the center console and center tunnel.
Cut the MDF into pieces with the jigsaw to make the sides of the box. Cut two pieces for the front for a little additional strength. On the two front pieces draw the outline of the subwoofer using the template provided with the subwoofer or by placing it upside down on the board and drawing around the edge. Do the same on the back piece to create the hole for the terminal cap.
Drill through the MDF inside the area to be removed, insert the jigsaw through the drill hole and cut out the area. Do the same for the second front piece. Use the same technique to cut the hole for the terminal cap in the back piece.
Attach all the pieces together using wood glue and the screws. The larger pieces should be on the outside and the thinner pieces should be on the inside of the joints.
Use the silicon caulk to seal the inside of all the joints and to make the enclosure a little more stable.
Place the speaker and the terminal cap in their holes and use a pencil to mark where the screws have to go. Remove the speaker and terminal cap and drill pilot holes for the screws. Replace the terminal cap and secure it with screws.
Connect the terminal cap and the speaker together using the speaker wire. Place the subwoofer in place and fasten it down with screws.
Move the subwoofer box to the back of the truck and place it where you intend to mount it. Check that it still fits in place. If it does, then you can mount it in one of two ways.
Attach two strips of heavy duty Velcro to the long sides of the speaker enclosure and in matching position on the floor. These will hold the speaker in place but still allow you to remove it if you need to. Attach the speaker wire from the head unit to the back of the subwoofer box.
Attach two brackets to the side of the subwoofer box with screws. Their exact location varies depending upon the mounting point you choose. Drill a hole through the carpet and into the metal around the cab and screw the box down using a metal screw. Attach the speaker wire to the terminal cap.
