Oh. What a duh moment for me, Joe!
I guess I am losing it a little after the years have started to pile on...
Didn't even realize I had been subscribed to this thread a while ago and had even posted back in Dec 2013 after you had finished.
Have you left the LH crossed at 70 or 80 to avoid the ringing?
I have always crossed my setup at 60Hz, long before horns were introduced, so it is not an issue for me regardless. However, you can EQ 90+% of it out with little effort.