The plans show the same 50Hz flare rate used by the original Klipschorn. Also the remaining "K" flares are 32 and 38Hz respectively with the same overall horn pathway length (approx. 64 linear inches). Both horns employ a 78 sq. in. throat area cross-section. A virtual Khorn knowckoff with a couple of improvements, funny since they were originally included in the 1946 Klipsch plans (a 12" driver size) but were subsequently dropped by Klipsch production some time later. These include back chamber "stuffing" and back chamber/channel axially aligned bracing to reduce vibration.

Most likely, the THROAT CAVITY OPENING of the Speakerlab "K" is the so-called "wrong" part, evidently copied directly from a post-1962 Klipschorn, being that it is 3" wide versus the 6" wide typically used for a non-K33 driver, such as the W1508S 8 Ohm driver used by Speakerlab. This is where the SL "K" MAY have been improved BUT I heard a pair of "K"s at the time, and in no way do I think that they suffered in the least from using the smaller slot size. I've NEVER heard a Klipschorn that beat them on the bass-end to this day.

DM