Are there room requirements for Atmos?

[BoomDog28]

Is there an ideal room size for Atmos? Recommended dimensions?

For example I have 20 ft ceilings in my main viewing room. Is it too high to pull off?

 

[KenM10759]

Probably not going to work unless you can somehow get the Atmos overhead speakers a lot closer, or compromise with some limited dispersion horns. I understand the Atmos overhead speakers should be somewhat diffuse, but probably not like shouting into Carlsbad Caverns.

 

[shadyJ]

In a high ceiling, I would get ceiling speakers with controlled dirictivity, like the Klipsch or Hsu -in-wall speakers. Like this or this.