If you are in a 250 foot by 200 foot auditorium with 3 or 4 story high ceilings, 3D sound is worth it. For a 17 foot by 20 foot, 10 foot ceiling home theater? I don't see any gains. The Atmos setup i first saw had downward firing speakers for there "voice of god" effect. The floor of any area is almost impossible to have any sound absorbent beyond a carpet, that is easy and safe to walk on. In a small room it's going to hit the floor and bounce up giving a echo effect, to me this ruins the effect. Most of the Dolby Pro Logic IIz AVR's i have seen in use had the front highs biamped with the right and left fronts. Why use a 9.1 AVR for 7.1 operation? If your a member of the Bel Air Circuit and can get DCI masters, and have the space for it, 3D audio would be well worth it. Last i looked Blu-Ray audio codec was 7.1, mostly 5.1.
While i am at it 5.1 surround served the cinemas fine for years as most of the surround speakers were mounted up high and pointed slightly down. So you got a sound field that sounded close to 3D. A personal friend of mine, and multiplex owner told me decades ago, "If they(studios) really wanted to do it right(sound), everyone would be down there wearing headphones."
Last edited by CinemaAndy; 07-01-2014 at 10:59 PM.