dpunk

That is a K-1000 horn, which was used in the early Heresy (and I believe in the early Cornwalls too). It was replaced with the K-700 (and K-600 in the Cornwall) around 1963 or 1964.

I hope you'll keep us posted on how it sounds when you're done:) This post explains how to notch out the 6.5 Khz peak in the M200 if you use a passive crossover: https://community.klipsch.com/index.php?/topic/10330-question-for-djk/&tab=comments#comment-74920

Yes, the Elliptrac 400. The M200 has a very low compression ratio, which supposedly gives it a more "relaxed" sound than other compression drivers. (It's basically a 2 inch diaphragm feeding a 2 inch exit, without a phase plug.) It would seem like a natural choice for the Elliptrac, but it has an upper limit of 4 KHz and therefore needs a tweeter. If I understood your post correctly, you have the Elliptrac and the HP640s? I've seen the HP640s in your other posts, but not the Elliptrac. I have a pair of EV HR90s sitting on top of my Belles, but they have 1.4 inch throats and will not fit the M200.

Has anybody tried the Community M200 driver on the Elliptrac horn? Forum member DJK has spoken very highly of the M200, and based on his comments this combination would seem to be an excellent choice in a 3-way setup.