Because I built my Theater 4s tall and thin, it was a natural to yank out the horn, plug the hole, and face them into the room corners, about 8" out. Doing this extends the bass and makes it stronger, but doesn't really change anything else. I was surprised to find that the lower part of the midrange handled by the Delta 15a was unchanged in level. I like the overall balance.Link below is a picture of the plugged front. Looking at it now reminds me to pick up some more DuctSeal on the way home tonight.
I'll have these at the New England Bottlehead meet this Sunday. We can listen to them as 7 Pi if there are corners, 4 Pi if not.
John