ACOUSTICS: Extremely important when it comes to mixing and recording music. An untreated room will compromise the accuracy of what you believe you are hearing from your monitor speakers. With that being said, strategically placed acoustic treatment is ideal. Since every room is different the approach should be different and no two configurations are alike. Basic acoustic treatment isn't complicated and by taming the room properly your decisions will become more accurate.
Mid and High frequencies reflect from hard surfaces such as walls in a similar way that light reflects a mirror. The rear wall and wall directly behind the speakers are a source of reflections so considered acoustic treatment in these locations. You don’t want to eliminate reflections completely but break them up so that they become less disruptive. This is not just the total solution because there are other aspects to think about. Bass Traps are good for the corners since low frequency builds up there giving you the perception of enough bass in a song but when you play it else where it lacks low end.
There are other methods that go hand and hand with theses but again this depends on the environment. Sonically you want a room that is accurate so what is coming from the source will translate better.