It says it on the WO plans page.
It said
Quote:Now take a protractor, and decide how you want to join your panels. You may wish to end-join them or miter them. The determining factor will be the abilities of your table saw. I recommend drawing the joints on your masterpiece too. That way you wont forget how you're planning to join each panel.
You'll be pleased to find out there is a way to join the panels (end-join) so that almost every angle in the design can be cut from one setting on your table saw. In other words, most of the angles in this design are identical, no matter what size you picked for the height of the enclosure. If you think this is getting rather amazing, wait until you hear the sound quality of the perfectly flat, extended response of this horn and the incredible efficiency!
Hope that helps a bit.
-Geoff