Pink Noise

This pink noise generator plays pink noise with an exact 1/f spectrum, made in your browser: every octave from 20 Hz to 20 kHz carries the same energy, so it sounds fuller and softer than white noise, a bit like steady rain. People play pink noise to sleep, to focus and to cover distracting sounds, and audio engineers use it to set speaker levels and tune rooms. This page does both: a sleep timer with a slow fade for bedtime, and a calibration level and band limits for your speakers. It works on phones, tablets and computers, through headphones, speakers or a home cinema system.

How to play pink noise

1. Turn your device volume down and press Play pink noise.
2. Raise the volume slowly. For sleep, stop as soon as the noise covers the sounds around you.
3. Choose Stereo for a wide sound or Mono to place it between the speakers.
4. Set a Sleep timer and a Fade out if you want it to stop on its own.
5. On a phone, turn on Keep playing with the screen off before pressing Play.
6. For speaker setup, press Set −20 dBFS and follow the calibration steps below.

What pink noise is

Pink noise is random sound whose power per hertz falls as frequency rises, by half for every doubling, which is 3 dB per octave. Since each octave up contains twice as many hertz, the two effects cancel and every octave holds the same energy. Our hearing groups pitch in octaves too, so pink noise sounds evenly balanced from bass to treble, where white noise sounds bright and hissy. Brown noise tilts further towards the bass and sounds like a low roar. It is also called 1/f noise, because its power is proportional to one over the frequency, and similar patterns turn up in nature, from heartbeat timing to river flows.

On the display, each bar is a third of an octave. Pink noise fills them all to the same height, and the yellow line shows where a perfect pink spectrum sits. If the bars match the line, the noise leaving the page is correct; anything your speakers or room change happens after that point.

What the readouts mean

Pink noise for sleep and memory: what studies found

Research on pink noise and sleep is more interesting than most claims about it, and also narrower.

• Ngo and colleagues played short bursts of pink noise to 11 sleeping volunteers, timed exactly to the slow waves of deep sleep. The slow waves grew stronger and people remembered more word pairs the next morning (Neuron, 2013).
• Papalambros and colleagues tried the same idea with 13 adults aged 60 to 84. Slow waves grew during the bursts, word recall improved more after nights with the bursts than after nights without them, and those whose slow waves grew most tended to improve most (Frontiers in Human Neuroscience, 2017).
• Basner and colleagues studied 25 healthy adults over seven nights in a sleep lab. Pink noise played through the night cut REM sleep by about 19 minutes, and earplugs did better than pink noise at protecting sleep from outside noise (Sleep, 2026).

Both studies timed each burst to the sleeper's own brain waves using EEG. A steady stream of pink noise from a speaker does not do that, so do not expect the same memory effect from this page. What steady pink noise can do is mask other sounds, and many people find it gentler than white noise for that.

Calibrating speakers with pink noise

Pink noise is the signal used to match speaker levels, because it has energy across the whole range and a meter reads it steadily.

1. Put a sound level meter, or a phone with a sound level meter app, at your main seat at head height, pointing at the ceiling. Set it to C weighting and slow response if it has those options.
2. Press Set −20 dBFS and choose the 500 Hz to 2 kHz band. That is the range used in cinema calibration, where speakers and rooms behave most evenly.
3. Choose Mono and play the noise through one speaker at a time, using your system's balance control or the speaker selection on your receiver.
4. Adjust each speaker's level until all of them read the same, for example 75 dB.
5. For a subwoofer, choose the 20 to 80 Hz band and set it to read the same as the main speakers, then fine tune by ear.

Film mixing rooms are set so pink noise at −20 dBFS reads 85 dB from each main speaker. Home theatre receivers use their own test noise at a lower digital level and aim for 75 dB; both come to the same loudness for the same film. With a surround system, run the surround sound test afterwards to confirm each channel plays from the right speaker. Pink noise is also the main signal in the headphone burn in tool, for anyone who wants to run in new headphones.

One speaker sounds different with pink noise

Pink noise makes differences between speakers easy to hear. Play it in Mono through each speaker in turn:

• Duller than the others: the tweeter is weak or damaged, or something covers the speaker.
• Boomy or thin: placement. Speakers near walls and corners gain bass; speakers in the open lose it.
• Hollow or phasey between two speakers: one speaker is wired in reverse. Swap its plus and minus wires and listen again.
• Uneven in the bass only: room modes. Moving your seat or the subwoofer changes them more than any setting.

To see the problem rather than hear it, play pink noise through your speakers and point a spectrum analyzer at them with your phone's microphone. Peaks and dips that stay put show where the speaker or room colours the sound.

Why you still need a sound level meter

The tool sets the digital level exactly, but the sound level in the room depends on your volume, amplifier and speakers, so you need a meter for calibration. Phone meter apps can be several decibels off in absolute terms, but they show the difference between two speakers well enough to match them. The noise is an exact pink spectrum made as a loop of about 22 to 24 seconds that repeats without a click. Pink noise is not a medical treatment for insomnia or anything else.

Pink noise questions