Pink Noise

What makes it pink

Pink noise has equal power in every octave rather than at every frequency. Because each octave upward covers twice the span of the one below, that works out to a fall of about 3 decibels per octave — which is why the hiss that makes white noise tiring is simply not there.

That slope is not a stylistic choice. It is the arithmetic of "equal energy per octave", and it happens to be the shape a great many natural sounds have: rain on a roof, wind in trees, distant traffic. It is probably why most people find it easier to sit with.

White, pink or brown

Think of it as a tone control across the three. White is flat and hissy; try it. Pink takes the top off. Brown takes far more off and leaves a deep rumble; try that. Nothing about the sequence is better or worse — it depends on what you are covering and what your ears prefer.

For something with texture rather than a steady wash, Rain Sounds is a recording rather than generated noise.

How it is made here

The noise is generated in your browser rather than downloaded, using a well-known filter that shapes white noise into the pink slope. Nothing is streamed, so it uses no bandwidth once the page has loaded, and there is no loop for your ear to catch.

The slope is checked rather than assumed: the build measures the generated sound in octave bands and confirms it really does fall at about 3 decibels per octave. A wrong number in the filter would fail that check rather than quietly sounding a bit off.

What this page does not claim

It plays a sound. Pink noise turns up in sleep and memory studies from time to time, and you may have seen a headline about it, but this page makes no claim about sleep, memory, focus or health, and nothing here is medical advice. Use it if it helps you; stop if it does not.

White vs Pink vs Brown Noise explains how the three differ and what the research says.