The system I heard had a B&C DCM50 (based on an old Western Electric driver) as the midrange and Fostex operating down to 4KHZ. You should try disconnecting the tweeter in the Klipsch and let the Fostex handle the entire frequency range. It's a far superior transducer to any of the Klipsch drivers. And for not a lot of cash, you can replace the midrange driver with a DCM50.
I have kept the stock Cornwall internals. I did a frequency sweep to find out in my room, the speaker's top end rolls off at 13kHz -3db. So with a little help of a friend, setup a 2nd order crossover at 13kHz. So the T500A mkii is playing with the Cornwall's tweeter.
shadorne, Dave, thank you for the kind words. I hear Symposium vibration control systems work very well to my ears.
If you look closely, the Cornwalls are on double-stacked Rollerballs which changes the speaker dramatically for the better. Then I was able to get ride of surface resonances on the speaker cabinet by using a Svelt Shelf.
This Cornwall experiment has turned out perfect for me. 102 db Sensitivity, near full range, perfect for my amps.