2008 Road Warrior Class C Motor Home Outdoor Subwoofer - Tricks Of The Trade

This is the '08 Road Warrior Class C motorhome/toy hauler that we've been working on for the last few months. The last step in the installation is to build an outdoor subwoofer enclosure to complement the roof-mounted marine speakers we installed last month.

There is a large space behind the passenger-side rear tires that is perfect for a large subwoofer enclosure. Better yet, it's protected by the mudflap for long-term durability.

I like to draw out the subwoofer enclosure design before I start building, and here you can see the box design, panel dimensions, and panel quantities. I like to be efficient, so I try to find the best pattern layout that enables me to use as few sheets of wood as possible.

The box dimensions and woofer specifications are run through a box design program to make sure the design will work correctly. This is a very large enclosure to maximize efficiency in the outdoor environment.

Construction always starts from the inside out, especially with slot-ported boxes like this one. The woofer baffle and portside are glued with wood glue and brad-nailed together. Screws can also be used to attach the panels. This enclosure was built using 1-inch MDF.

Next, we'll work on the back and side of the enclosure. The two parallel panels form the port; notice how the edge of the port is rounded to minimize port noise.

Finally, the bottom of the enclosure is glued and nailed in place with the enclosure upside down on the bench. Notice how the bottom is shorter than the top; this will form a vent to fire the output at the ground.

With all of the panels glued and nailed in place, a handheld wood router with a 1/2-inch roundover bit is run over each edge for a smooth finished appearance.

To waterproof and protect the enclosure, we use Dupli-Color Truck Bed Coating. It is available at most auto parts stores, and works great on multiple materials. Spray two coats, allowing 15 to 20 minutes drying time between coats, and wear your respirator because this stuff stinks.