Unfortunately, boundary loading won't be an option, which brings me back to the problem of depth vs. horizontal expansion. That's why I brought up the dual-angle midbass horns. The transition from one coverage angle to the next is almost exactly halfway down the horn, not near the mouth (although you did answer a future question). I found a third midhorn designed that way, on the Speakerstore.nl site. Are these horns a variation of a conical design? If so, this could solve my depth problem (even if it creates others).I've bookmarked your link to room corner characteristics. It's valuable information to non-techies like myself! I've done as such with several of your posts, Wayne!
The reason why I haven't yet shared this design is because I want to make sure that the forum isn't designing it for me. I'll post an outline of it for reviews and guffaws when I'm done tweaking on paper!