MB, I ain't not horn designer. Just following the plans from audioheritage. My post above was how I would take the dimensions from that plan and lay it out on the board. Not everybody has a CNC machine, so some of us have to do things the old fashion way, with trammels (compasses) and rulers.In my experience, I've found it difficult to accurately apply angles on a board. Much more accurate to use a bit of tri and layout with x/y coordinates. I just translated the dimensions from the plan to the x/y coordinates.
gar.