What is pink noise?
Pink noise has equal power in every octave. The band from 100 to 200 Hz carries the same energy as 1,000 to 2,000 Hz, or 10,000 to 20,000 Hz. Compared with white noise, the power per frequency falls by 3 decibels each time the frequency doubles, so the hiss is tamed and the sound becomes fuller and rounder.
Because we hear pitch in octaves, pink noise sounds evenly balanced to most people, neither hissy nor boomy. Engineers use it to tune sound systems for exactly that reason, and it is sometimes called 1/f noise, because its power is inversely proportional to frequency.
What does pink noise sound like?
Steady rainfall on a roof, wind through leaves, a gentle waterfall or the rush of a shower from the next room. Many natural sounds have a roughly pink spectrum, and so do the fluctuations in heartbeats, music and even river levels. That familiarity may be why people often find it calming.
Pink noise and deep sleep: what the research says
Pink noise gets attention in sleep science for a specific reason. In a 2013 study in the journal Neuron, Ngo and colleagues played short bursts of pink noise timed precisely to the slow brain waves of deep sleep. The bursts strengthened those slow waves, and the volunteers remembered word pairs better the next morning. A 2017 study by Papalambros and colleagues in Frontiers in Human Neuroscience found a similar effect in older adults.
It is important to be precise about this. Those studies used brief clicks of pink noise, synchronized to brain activity measured with EEG, not a continuous stream from a speaker. Continuous pink noise has not been shown to do the same. What steady pink noise does well is mask disturbing sounds while being gentler than white noise, which is a perfectly good reason to sleep with it.
Pink noise compared with other colors
| Color | How it differs from pink | Choose it when |
|---|---|---|
| [White](/) | More treble, sounds hissier | You need to cover voices or sharp sounds |
| [Brown](/brown-noise/) | Much more bass, deeper | Pink still sounds too bright to you |
| [Green](/green-noise/) | Pink with the mid range emphasized | You want a more natural, forest-like tone |
| [Grey](/grey-noise/) | Shaped to sound equally loud at every pitch | You have sensitive hearing or tinnitus |
Ways to use pink noise
- Sleep: set it just loud enough to blur the sounds around you, then add a sleep timer if you prefer silence later.
- Work and study: pink noise covers office chatter better than brown noise but is less tiring than white. The Block out speech quick mix pairs it with a stream.
- Babies: some parents find pink noise less harsh than white; the same safety rules about volume and distance apply. See white noise for babies.
- Testing speakers and rooms: pink noise is the standard signal for checking frequency response with a real-time analyzer. The download gives you a clean, gapless pink noise file for that.
Frequently asked questions
Is pink noise better than white noise for sleep?
Many people find pink noise more pleasant because it has less treble, so it is easier to leave on all night. White noise covers high-pitched sounds slightly better. Neither has been proven superior for sleep in general; choose the one you find most comfortable.
Does pink noise improve memory?
Studies that played short bursts of pink noise timed to deep-sleep brain waves found better memory the next day. Those used EEG-synchronized clicks, not continuous noise, so playing pink noise all night has not been shown to boost memory.
Why is it called pink noise?
By analogy with light. White light has every color equally; light weighted toward lower frequencies looks reddish. Pink noise is weighted toward low frequencies, but less strongly than red or brown noise, so it is pink.
Can I use this pink noise to calibrate speakers?
Yes. It is generated with the standard Paul Kellet filter, which is accurate to within a fraction of a decibel across the audible range. Use the download for a gapless file to play through your system.