White noise


Audio: white noise (0:02)

White noise
Figure: white noise

white noise plays white noise. The white noise figure shows its spectrogram.

White noise is unpitched sound in which power is equally distributed throughout the spectrum.

The spectrum of white noise is analogous to the spectrum of white light. Every frequency is present in white noise. Every frequency has the same amplitude.

The spectrogram of white noise is a flat crinkly straight line. The spectrogram is unique and completely diagnostic of white noise. It shows that all the frequencies are present and that each frequency has the same amplitude.

White noise sounds bright and hissy. This is because high frequencies have the same amplitude as low frequencies.

Some people find prolonged exposure to white noise stressful, others find it calming. White noise machines are even sold as a cure for poor sleep although some use pink and red noise as well as white noise and some combine noise colours with ambient sounds from nature.

White noise is the ultimate frequency rich sound. It is rarely used on its own for writing music but it comes into its own in sound effects. White noise is the most commonly used sound source for making effects.