How to Apply Fabric to a Speaker Box

Place bath towels on a work surface. Place the speaker box on the towels with the speaker hole facing up. Measure the height and width of the speaker panel surrounding the hole -- typically this will be the front of the speaker, although for a subwoofer, the hole could be on the bottom. Write these measurements down.

Place the foam core board on the towels. Draw a box outline of the board that matches the measurements written down with a straightedge and pencil. Measure an inch in from the outline and draw another box inside the first one with the straightedge and pencil.

Cut out the inner box outline with the straightedge and a utility knife. Pull the cut foam core out and dispose of it. Cut the outer box outline with the straightedge and utility knife. Place the excess board pieces aside.

Smooth the inside cut edges of the foam core piece with fine-grit sandpaper for 30 seconds. Wipe the excess foam dust off the edges with a soft cloth. Smooth the outside cut edges of the foam core piece in the same manner.

Place a piece of speaker grill cloth on the towels. Place the foam core board on top of the cloth. Draw an outline around the foam core board onto the cloth with a pencil. Remove the foam core board from the cloth. Cut out the outline on the cloth with a straightedge and utility knife.

Place the board vertically on the towels. Apply a line of bonding glue around the edges of the board. Place the cloth vertically on the board so that the board is completely covered up. Press the cloth against the board and hold it there for 20 seconds. Let the bonding glue set overnight.

Place the speaker box on the towels so that the open end is facing up. Line up the board over the open end of the box with the cloth facing up. Place the board against the open end, and press it in so that it adheres by friction.