Box Building 101
By Jason Anderson
Installer Institute

Jason Anderson, the director at the Installer Institute, contributed this How-To Guide on building subwoofer enclosures and the benefits of custom builds. Here’s a sneak-peak at the article. Be sure to check out MECP.com to learn more!

Jason’s Tips:
Custom subwoofer enclosures can be a profitable part of any installation. Knowing how to sell it and being able to build it quickly demonstrates your skills and knowledge as a certified installation technician.

Before starting any fabrication, it’s vitally important that you have a strong understanding and respect for power tools like the table saw, panel saw, and router. It’s also important that you have the appropriate support for large sheets of medium density fiberboard, or MDF, and the correct safety items (e.g., push sticks) when dealing with smaller cuts.

Step 1
Design your enclosure based on manufacturer specified volume recommendations. Remember, the simple calculations for volume are width (W) x height (H) x length (L) - in inches - divided by 1,728. This formula will give you the cubic feet measurement. Remember to subtract the thickness of the material for each end so you have the internal, not external, dimension.

Example – External Dimensions of 32”(W) x 15.5”(H) x 13.76”(L) using ¾” material

This would be an internal dimension of 30.5”(W) x 14”(H) x 12.26”(L) = 5235.02 cubic inches. Since there are 1,728 cubic inches in one cubic foot, dividing the total volume by 1,728 will give you the total internal volume in cubic feet.

In this case, 5,235.02 divided by 1,728 = 3.03 cubic feet (rounded off). Knowing the correct internal volume is very important, especially in vented (ported) enclosures.

Step 2
When starting from a full sheet of MDF, lay out the dimensions so you make the most efficient use of your material with the least waste. You can do this easily on graph paper or just by drawing lines right on the MDF. Make the largest cuts from a panel saw or large table saw. This allows simple rip and crosscuts against a square reference point. From there, you can trim all of the pieces to the final dimensions on a table saw.

Step 3
Now that the panels are cut (and before any assembly takes place), rabbet a lip around the edge of the side panels about 1/8” deep. This allows for an area to tuck the carpet into once the enclosure is built. If you have ever carpeted an enclosure, it’s always the sides that seem to be the hardest to finish off with a clean look.

Step 4
Assembly is next. At Installer Institute, we recommend attaching the top and bottom to the sides of the enclosure first. This will allow you to adjust edges to match up perfectly with the front and back of the enclosure. Please note that the routed lip must face toward the outside edge. We recommend using a pneumatic crown stapler or brad nailer with the appropriate length fasteners and wood glue. The wood glue provides strength to the joint and the fasteners simply hold it in place while the glue dries. If you are liberal with the glue, the seams will not leak any air!

Check out Jason’s full article here. You’ll find the finishing process, including important tips on the vent (i.e., port) construction as well as mounting the enclosure in the vehicle.

If you would like to contribute your expertise to the MECP community, please contact MECP@MECP.com to submit your ideas for future “How-To” articles!