I don't follow much of the forum, but this thread appears to have been "all over the map".
First, this thread contains discussion that seems to walk a fine line with respect to commercialism. Fortunately there seems to have been some "self-correction" which is a positive thing.
Second, there were statements that Paul Klipsch "copied the Hartsfield", that he did not have measurement equipment "in the beginning", and that the first 10 K-horns were all different. I can positively state that Paul had no love for the Hartsfield, and that he made tape recordings of Hartsfield and Klipschorn outputs to demonstrate the differing degradations contributed by each. The Klipsch archives show clearly that Paul's earliest efforts (pre-1940) were accompanied by acquiring measurement equipment, as meager as it may have been by today's standards. He made his response curves one point at a time for years. Meager equipment seldom deters brilliant minds from getting the answers they are after. It just takes more elbow grease.
Also, after the first sucessful Klipschorn prototype (X3 woofer and X5 squawker) the next 12 woofers were identical units built for him by Baldwin Piano Company in Cincinnatti. Whether the top ends were identical or not is unclear, but we do have the records of buying 12 Western Electric 713A's at that time. The following 7 units were built in Reed's cabinet shop, and "were all different". In large measure, the differences were cosmetic. The one definite technical evolution was the connecting of the sinuses with the primary back air chamber.
Mainly trying to keep the historical record clear.