Sound masking and white noise can be used for the same purpose, to block distracting sounds in the environment. Whereas white noise does this by replacing the distracting sound with sheer volume, sound masking focuses on specific frequencies while allowing other sounds to remain audible. In an office setting, sound masking is used to reduce the intelligibility of speech and other distracting noises, while white noise is better suited to create background sound to help people sleep, for instance.