Recording studios must deal with the acoustic of the room in order to make a living or generate income from their studio. Wall reflections and room modes must all be addressed in order for the engineer to hear the sounds produced from the musicians instead of the room sound. The engineer must separate the room sound from the mixed sound.
The primary, secondary, and tertiary side wall reflections in recording studios must be controlled in some acoustical manner in order to minimize their impact at the monitoring position. The engineer wants to hear the sound that comes directly out of his speakers and reaches his ears before the side wall reflections interfere with this wanted direct sound. Similar room boundary reflections must be controlled for the sides and rear channel recording.
In the recording studios I have seen, special care is given to placing the entire monitoring system in a place in the room that is free from room mode issues. Room modal issues occur between two parallel surfaces and their intensity varies with room volume. Room modes can hide or over emphasize certain frequencies. We want to hear everything at the mix position. We don’t want the room hiding or producing anything extra for us to have to deal with. Dealing with artistic, sensible, individuals can produce enough “sound” of their own let alone having to deal with the room mouthing off.