Cut out the circular openings with a router. Sand all rough edges. 6. Brace the speaker box with 1-inch x 1-inch (2-1/2 cm x 2-1/2 cm) strips of wood (battens). Cover 60 percent of each interior edge with a batten. Screw the batten into the MDF. 7. Fit the cut pieces together to make sure they match up. 8.
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