The shape of a room affects how sound is distributed in that space. To illustrate this, we will depict sound waves as traveling in rays that reflect off of surfaces according to Snell’s law: the angle of reflection equals the angle of incidence.
From ray studies, we can see that concave forms tend to focus sound in general, while convex forms help diffuse sound. Thus, many concert hall acousticians refrain from using concave forms and try to add additional convex shapes to increase diffusion through the hall.
We can extend these ray studies to an entire concert hall, and construct ray diagrams which show how sound coming from a source on the stage is spread around the room.
The goal is to distribute sound energy evenly in the concert hall: Look for areas where sound rays converge, which is an indication of sound focusing, and change the room shape to minimize it.