Building an MDF and Fiberglass Subwoofer Enclosure

Building An Mdf And Fiberglass Subwoofer Enclosure Stereo Complete

The finished enclosure with all the subs mounted is quite a sight. Keep reading to see how it was made.

The finished enclosure with all the subs mounted is quite a sight. Keep reading to see ho

We’ve been asked several times over the last few months how sub boxes are built, and lucky for us, the crew at Superior Auto Sound, in Phoenix, Arizona, snapped plenty of photos while they built the enclosure for Steve Burkett’s Yukon. Follow along to see how a few sheets of MDF (medium density fiberboard), body filler, fiberglass, and fabric were transformed into a flowing enclosure that houses four Kicker L7 12-inch subwoofers.

1. To contend with the power draw of the audio system, a 275-amp Ohio alternator replaced the stock unit.
1. To contend with the power draw of the audio system, a 275-amp Ohio alternator replaced
2. Another worthwhile upgrade was a layer of FatMat to the sheetmetal of the Yukon, especially the roof, which will ensure that the audio is pure and not influenced by outside noises.
2. Another worthwhile upgrade was a layer of FatMat to the sheetmetal of the Yukon, especi
3. With the third-row seat removed, the guys at Superior Auto Sound had a better idea for the rear of the Yukon.
3. With the third-row seat removed, the guys at Superior Auto Sound had a better idea for

4. Taking measurements for the size of the base, the first step in assembling the box was framing the ports. The 3/4-inch MDF was glued in place and secured with a brad nailer.
4. Taking measurements for the size of the base, the first step in assembling the box was
5. You can see that the wedge-shaped port areas will be on the bottom of the enclosure. A curved back and sides were mocked up to make sure everything was correct before any permanent steps were taken.
5. You can see that the wedge-shaped port areas will be on the bottom of the enclosure. A
6. The center of the box got a double dose of ½-inch MDF down the center and the open ends of the ports were beveled with additional pieces of MDF. The interior corners were smoothed with body filler to create a fillet.
6. The center of the box got a double dose of ½-inch MDF down the center and the open ends

7. The ¾-inch MDF was used to create the rings for the square Kicker subs. They were positioned carefully to ensure symmetry and to keep plenty of clearance for the cones.
7. The ¾-inch MDF was used to create the rings for the square Kicker subs. They were posit
8. Fabric was stretched over the box and stapled into the frame. We’ve seen shops use fleece or jersey, the same material as a T-shirt. It will provide the contour of the box and keep the curves equal on both sides.
8. Fabric was stretched over the box and stapled into the frame. We’ve seen shops use flee
9. The outside of the fabric was coated with a thin layer of epoxy filler that’s easy to sculpt into the exact shape. It was allowed to cure overnight.
9. The outside of the fabric was coated with a thin layer of epoxy filler that’s easy to s

10. With the exterior coated for aesthetics, the interior was layered with chopped fiberglass to bulk up the strength.
10. With the exterior coated for aesthetics, the interior was layered with chopped fibergl
11. A paintbrush was used to apply resin to the chopped fiberglass. It’s important to get a uniform coat to ensure that the fibers all get their share of the resin.
11. A paintbrush was used to apply resin to the chopped fiberglass. It’s important to get
12. After the exterior was sanded smooth, Weldwood spray glue was applied to both the box and the vinyl upholstery.
12. After the exterior was sanded smooth, Weldwood spray glue was applied to both the box

13. A heat gun was used to make the vinyl flexible for the complex curves.
14. Excess vinyl was wrapped around the back and stapled into position.
15. Here are the goodies, four Kicker L7 subs, and crossovers, amps, and wiring.