Room tuners for hire and others who model a room should do away with as many ninty degree intersections as they can. I have seen many store bought rooms displayed on these pages and on 6 Moons that are overtreated and overcorrected when in fact the basic geometry is still overlooked. These flaws include soffits that house mechanicals in retangular enclosures hanging overhead and running around the room to give the appearance of a tray ceiling. These trays inhibit the airflow in the room and cause major frequency and phase aberrations. If they were simply addressed with an angle that would redirect the flow of air gracefully at the listener then less restrictive foam and fiberglass need apply. Would you put a ninty degree bend in a tuned header of a race car.
Tom
Tom