[mohak]

Acoustic treatment deals with the acoustic quality of the room from a listener's point of view. If you monitor in a control room that has been designed using the correct acoustic treatment, what you hear is likely to be more accurate than the same recording played back over the same speakers in an untreated room.

Soundproofing is specifically designed to increase the degree of acoustic isolation between the studio and the world outside -- cutting down on noise that leaks into or out of the studio.