In psychoacoustics, white noise is used to combat noise and in the field of tinnitus retraining therapy as a masker; Noise and other background noises are subjectively perceived as less loud and annoying if they are superimposed with white noise. Noise in which all frequency components sound roughly equally loud is referred to as 1 / f noise. It has a power density spectrum that decreases with frequency.
In stochastics, white noise describes a discrete stochastic process of uncorrelated random variables with an expected value of 0 and constant variance. It is weakly stationary and has a constant spectral density. The white noise represents the simplest stochastic process, but many more complex processes and time series are constructed from them, such as the random walk or ARMA processes.
