Let's consider building a 12-inch \small 12\text{-inch} 12-inch speaker box with the dimensions of 18 " × 15 " × 20 " \small 18" \times 15" \times 20" 18" × 15" × 20" for its width, height, and depth, respectively, using a 3 4 " \small \tfrac{3}{4}^" 4 3 " thick board. SHIY2.

12 inch speaker box dimensions