Robert Harley and F. Alton Everest, names you doubtless know, dislike nonrectangular rooms because while they have resonant modes, these are much less predictable. I have a cathedral ceiling, and was advised by an acoustic treatment pro to take the rectangular part of it seriously, as if the sloped parts weren't there. That's all I can offer you, I'm afraid. Start from an analysis of the room as if the walls (or ceiling and floor) parallel to each other are the only surfaces you must deal with. How to continue? ??????
Room acoustics - yet again
I have the books and the theory of room acoustics for rectengular enclosed rooms. Any guidelines for irregular (ie partly-cathedral ceilings, multiple openings to the listening room) ? Or is it the usual measure-listen-change ? My problem is finding a reasonable starting spot and tewak from there.