The last discussion I had with Bruce Edgar concerned the National Company folded horn known as the National Catenoid Loudspeaker System. The patent was filed and held by Sam Bryan of the Laboratory of Electronic Engineering (LEE). The horn was manufactured by LEE and National between 1955 and 1963.
The horn was a folded design and of considerable interest to Edgar. He was also kind enough to send copies of the factory drawings to me. Unlike the Klipschorn, the Catenoid doesn't split the driver output which, of course, leads to distortion.
From the patent:
LEE_catenoid.jpg
I have a large archive of vintage audio literature. This is an orginal marketing brochure for the LEE Catenoid (published by LEE).
LEE_1.jpg
The speaker used the University 6200 12" for the bass horn driver, Lansing P8RX 8" direct radiator midrange and University 4401 horn tweeter.