My designs are a long drawn out process. I start with the basic math and formulate a design goal. I then factor in a size goal then start folding on a CAD program till i can get as near as i can. Then i start a wave form/pressure(hydrodynamic) program which more or less refines the flow. Then i go thru structural methods to assure there will be minimal resonances then sit down with CAD and several dozen papers filled with numbers and work on it till i get something that is as close to my original design goal as i can get.Last horn took 6 months to design and build a test horn and test. ron ( i may be slow ,but i eventually get there)