With the box sealed and nailed together we can move onto cutting out the speaker holes. Here, a pre-cut ring for 10-inch subs is used as a guide. Its slightly oversized outer diameter will aid in a evenly spacing the subs. Notice the 211/42-inch recess left on the back side of the box for the amplifiers to be sunken into and hidden from sight. Once the general outlines are spaced out we need to find the centers of the cut outs for preparation to use our circle cutting guide router attachment. These holes can be easily cut out with a jigsaw, but for the finish we're trying to achieve a "perfect circle" that will make things much easier.