A friend of mine, 82 years old and the best engineer I know, has always told me, "Polycylindricals scatter too much" and, since he told me that I have noticed that I've never used a room treated with poly's that I thought sounded really great, but I've been in many rooms that didn't use poly's (Capitol, Paramount Stage M, Sony Scoring Stage) that I thought sounded really great. I do seem to remember that RCA (which many people would probably say did sound great) used horizontally-oriented poly's, and I wondered if that might be a better-sounding way to use them.