If anyone is interested, there is a thread on diyaudio.com discussing Dr. Geddes's waveguide theory. Anyway, some of us had worked out a spreadsheet with the profile, but it wasn't 100% correct. One needs to adjust for the exit angle of the compression driver used. Dr. Geddes and I came up with an algebraic solution to the problem and I am updating the spreadsheet to account for the correction.
Just thought I'd post here in case anyone is interested...
Here is the link.
