The info in the Klipsch products portion of this website for the MCM-4 has some old information. I told Amy about it at one point. They finally have the right picture now though. The MB-KPT-XII has not been available for 2-3 years. I have the latest. It is the KPT-305. That is what is in the picture I posted above, and in Klipsch products section. The older XII was a 12" driver on a tractrix horn, the replacement 305 is an 8" driver on a modified tractrix horn (K-402). You have to be careful of the delays, and crossover frequencies too. i have seen several different implementations. I don't use any of those. The cinema brochure has a lot of setup info but it is for "behind the screen".
I can see now that I have the older K-510 UHF horn on my setup. No mumps.