In short, white noise is not just one pitch of "TV static". There can be many pitches in white noise, and also many other types exist: brown noise, pink noise e

In short, white noise is not just one pitch of "TV static". There can be many pitches in white noise, and also many other types exist: brown noise, pink noise etc. It also can be mixed in to provide an audio experience. Human mind is excellent in recognising patterns so if one is using it for sleep/anxiety reduction purposes, it needs variety. This is why a noise generator producing nature sounds never work, but a fan does.