Speakers and Treatment of Live Recording Room

I am nearing completion of a live recording room (22' x 15' x 10') that has gypsum on walls and ceiling. I am considering placing an acoustic drop ceiling just below the hard ceiling. I also am considering placing diffusors in the drop ceiling so as to not lose all the acoustic energy of the room. As this room is going to be used to record music in the classical/sacred genre, I want to achieve a decent amount of natural reverberation. I would appreciate any suggestions on wall treatment for a live room. More diffusion than absorption? Or, perhaps there is a good ratio between the two as a starting point. Also, what are some suggestions on placing speakers in this room (location, distance from walls, etc.). Thanks, AB

AB With the dimensions you gave, you have some serious mode problems with numerous double incidences below 250Hz. I would suggest moving a wall or lowering the 'hard' ceiling. Adding 2 additional layer of 1/2" gypsum board to the ceiling will cure this. Are those dimension exact to the fraction of an inch? Why do you want to drop the ceiling? You must trap the room and corners are the most effective place for LF trapping. Cheers, John

The exact room dimensions are in the image. Not shown in the image is the ceiling height, which is 10 feet. On the one wall, at 95" from the right wall there is a steel beam that has been boxed around. The dimensions of it is 28.5" wide and is 10" into the room at the bottom and slopes upward to 18" into the room at the top. The 51.5" slant on the other wall is the doorway. There is also a double-pane plate glass window centered on the wall section that is 162". The window is 54" wide by 28" high. The thought behind the drop ceiling was to eliminate floor-to-ceiling reflections, especially since the floor will be hardwood. Regards, AB

It is our hope to achieve a room reverb time in the range of 1.5 second, if that is possible. Regards, AB