How to Install a Car Subwoofer

 

One of the cheapest and easiest upgrades for your car's audio system is a DIY subwoofer. A subwoofer improves the sound of your system by enhancing bass and adding depth to an otherwise flat-sounding system. Installing your own is simple and will have your system pumping in no time.

What You'll Need

For this project, you'll need 3/4-inch-thick medium-density fiberboard, PVA glue, screws, clamps, silicone, carpeting, a terminal cup (which is a plastic cup with terminals to connect the speaker wires to the speakers), speaker wire, and the subwoofer. For tools, you'll need a tape measure, pencil, screwdriver, jigsaw, drill, and soldering iron.

There are several brands of subwoofer speakers on the market, catering to all budgets. Common speaker sizes are 10, 12, 15, and 18 inches. Measure the space to fit the box to make sure you don't buy a speaker that's too big. Plan to build the box around the speaker you buy and the space available.

The best place to mount the box will usually be in the trunk or luggage compartment of your car. An efficient design is a rectangular box with the speaker-mounting surface raked back on an angle. The flat rear surface of the box should sit against the back of your rear seat, leaving the speaker facing outward into the luggage area.

Construction

1. Measure the front face of the box to size using the measurements you took, leaving at least a few inches above and below the outside diameter of the speaker.
2. Cut the remaining three sides of the box to size.
3. Use the speaker as a template to create the opening for the subwoofer, marking out the drill holes for the mounting screws.
4. Use a jigsaw to cut the hole for the speaker, and predrill the mounting screw holes to a slightly smaller size than the actual screws.
5. Depending on where you intend to route the speaker wires, predrill and cut a hole in the rear or side panel the same diameter as the terminal cup.
6. Fit the terminal cup, using silicone to seal and secure it in place.
7. Glue and then screw the front, back, bottom, and side panels of the box together. (Don't install the speaker yet.)
8. Seal all joints with silicone to create an airtight box.
9. Cover each panel with glue and apply the carpet, pulling it tight and spreading it across the back, side, and rear-panel surfaces.
10. Cut the carpet into segmented sections for the speaker holes rather than cutting a hole for a neater finish. Fold segmented sections and glue to the inside of the box.
11. Apply glue and carpeting to the front section.
12. Run wiring from the speaker through the hole in the front panel of the box and solder the wires to the back of the speaker terminals and the inner terminals of the terminal cup. Ensure you join negative to negative and positive to positive.
13. Fit the speaker in place and secure it with screws.
14. Place the speaker cover on the speaker and secure it in place in your car.
15. Connect the wires from your sound system—or from your amp if you have one—to the subwoofer. You're ready to rock.