An essential part of an electric guitar rig, speaker cabinets keep the sound directed and crisp. Making a cabinet is not too difficult with a few tools and it can be cheaper than buying a name brand cabinet. Perhaps you have a certain appearance in mind or just can't find what you are looking for. Don't skimp on the speakers as they will dictate the tonal quality and volume of the cabinet.
Step 1—Prepare the Speaker Board
Decide on how many speakers you will be placing into your cabinets. Keep in mind that twice the number of drivers doesn't necessarily mean twice the sound output, however more speakers are louder due to the increase in cone surface area. Measure the cabinet. It should be big enough to hold the speakers plus about 2 inches of clearance on each side. For example, if you are housing 2 x 12-inch speakers, the cabinet would need to be at least 28 inches high/long by 14 inches in depth.
Step 2—Make the Cabinet
Measure and cut out the cabinet. With a compass, draw the circles and cut out the holes in the front panel with a jigsaw. Cut on the outside of your circle so the hole/s end up about 1/16-inch larger than the speaker frame. Leave the back open to prevent overheating. An open back also means that you don't have to worry about internal volumes and calculations. Although a dovetail joint is best, you can use butt joints. Glue and reinforce the joints with the drywall screws. Leave to dry. Reinforce the joints inside the corners with triangle shaped stock pieces. Glue these into place inside the right angle joints.
The board holding the speakers is recessed about 2 inches. Place a cross member in the rear, big enough to accommodate the input jack.
Step 3—Install the Jack
Wire and install the jack plate and input jack. Mount the jack plate to the exterior by cutting a hole in the rear of the speaker box and screwing into place. Don't use a regular ¼-inch jack or a spring-loaded push button type terminal. These types will pull out during a gig. Solder all connections.
Step 4—Cover the Cabinet
You could spray paint the box black with paint but it will improve the look if you staple or glue velvet fabric, or short pile carpet to the box. This also improves the durability of the box if it is being moved about a lot.
Step 5—Affix the Hardware
Affix handles, wheels and other hardware to the box. You can also dress up your speaker box by attaching a grill to the front. You can choose to use commercial grille cloth or metal grate.
For better acoustics, line the inside of the cabinet with acoustically absorbent material. This improves panel damping.