DM: I understand the technique as a way for reducing throat overload distortion. However for home listening I am assuming the drivers are not being driven very hard to begin with. That is why I was wondering about the necessity of the initial rapid flare (rubber throat). You did mention a non-expanding pipe section. That is interesting, since such a section is found immediately after the rubber throat in the the Delgado & Klipsch article (JAES, 2000).

I had always assumed that was weak point in the design (the Jubilee) since 4 parallel walls (for about 5 inches after the radius reflector) would create standing waves. I had further assumed this "convenience" was considered too short to have an appreciable decrement.