What is white noise?

How to set it up

1. Play White noise and listen for ten seconds.
2. Play Pink noise. Notice how the hiss softens.
3. Play Brown noise. Now it is a rumble. All three are random noise; only the balance of low and high has changed.

Why is it called white?

The name comes from white light, which contains every visible color in equal measure. White noise contains every audible frequency in equal measure. Other noise colors borrow the same idea: pink and brown noise lean toward the low end, like reddish light.

Why does white noise sound so bright?

We hear pitch in octaves. Each octave up contains twice as many frequencies as the one below. In white noise, every frequency has the same energy, so higher octaves carry more total energy and sound louder. That is why white noise sounds like a hiss rather than a balanced roar.

What white noise is used for

Sleep, by covering sounds that would wake you. Focus, by blurring speech. Babies, as a steady background. Privacy, in offices and clinics. Tinnitus, by reducing the contrast with silence. Engineers also use it to test speakers, rooms, and electronics, because it contains every frequency at once.

Examples of white noise

True white noise is rare in nature. Things that come close: a radio tuned between stations, a hissing steam pipe, a shower close up, an air vent. Most natural sounds, like rain and waterfalls, are closer to pink noise.

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