Just like light, sound waves can pass through even the smallest hole or opening in holes, walls, or any material. Acoustic foams are installed to reduce noise pollution as they remove echoes and background sounds not by blocking the sound but by absorbing it. Acoustic foams are used to control the reverberation sounds make and this is quite different from soundproofing.
Acoustic foam will reduce the pick-up of loose frequencies when recording making the recording and monitoring process much cleaner and defined. This results in more accurate recordings and allows you to hear exactly what is intended to be recorded without the room having a unfavourable effect of the end result.
If no acoustic treatment is installed in the studio the reverberation can be so long that practice sessions can be a chore and not a pleasure. Recording will be difficult to control and mixing will be difficult to master. When recording or trying to monitor a recording you want to take the room out of the mix, it needs to be controlled. What you really want and need to hear is the source, whether you are recording or monitoring. What you don’t want is the room telling you what to hear and what to record. Imagine the room as a big instrument. If that instrument is not tuned correctly you will only hear an out of tune room. Not a room that works in harmony with the recording or sound.
