Pink Noise Generator
Press play for smooth, continuous pink noise, the balanced “steady rain” sound with equal energy in every octave. Use it for sleep, focus or masking background noise, or switch to calibration mode for an exact −20 dBFS band-limited test signal to level your speakers and subwoofer.
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Octave-band levels. Pink noise has equal energy in every octave, so the bars sit level; white noise would rise 3 dB per octave.
How to use the Pink Noise Generator
- Press Play pink noise. Start with your device volume low and raise it slowly.
- Shape the sound with the tone tilt slider (darker for sleep) or the Below 1 kHz band for a softer, rain-like hiss.
- Set a sleep timer and fade-out so the noise ends gently after you fall asleep.
- For speaker calibration, press Speaker calibration: −20 dBFS pink noise, 500 Hz–2 kHz, left channel. Adjust the receiver's channel level until your SPL meter reads the target, then switch to Right only and repeat.
- Need the signal elsewhere? Press Download 30 s WAV and play it from any device or audio software.
Pink, white and brown noise compared
All three are random signals; they differ only in how their power is spread across frequencies. The slope is given per octave (each doubling of frequency):
| Noise colour | Power spectral density | Slope | Energy per octave | Sounds like |
|---|---|---|---|---|
| White | constant | 0 dB/octave | +3 dB each octave up | TV static, hissing radiator |
| Pink | ∝ 1/f | −3 dB/octave | Equal in every octave | Steady rain, wind in trees |
| Brown (red) | ∝ 1/f² | −6 dB/octave | −3 dB each octave up | Waterfall, distant rumble |
Because a sound level meter, a real-time analyser with octave or third-octave bands, and human hearing all work in proportional (logarithmic) bands, pink noise reads flat on them. That is what the octave display above shows, and it is why audio engineers use pink noise rather than white noise for measurements.
Calibration levels and bands
| Use | Signal | Typical meter target |
|---|---|---|
| Cinema screen channels (SMPTE RP 200) | −20 dBFS RMS pink noise, 500 Hz–2 kHz | 85 dBC, slow |
| Home theater / AV receiver | −20 dBFS RMS pink noise, per channel | 75–79 dBC, slow |
| Studio near-field monitors | −20 dBFS RMS pink noise, per speaker | about 73–83 dBC depending on room size |
| Subwoofer | pink noise, 20–80 Hz | matched to the mains (C-weighted meters under-read deep bass) |
Set your computer, browser tab and audio interface volume once and leave them unchanged while you calibrate, otherwise the readings are not comparable. Bluetooth speakers and phone speakers apply their own processing, so use a wired connection for accurate calibration.
Tips for using pink noise for sleep and focus
- Keep it quiet. The noise only needs to be a little louder than the sounds you want to mask. For overnight use, health bodies such as the WHO recommend keeping sound exposure moderate; well below normal speech level is a sensible ceiling.
- Tilt it darker (−2 to −4 dB) or choose the Below 1 kHz band if the hiss bothers you; it still masks traffic and voices well.
- Use the fade-out. An abrupt stop can wake light sleepers; a 1 to 5 minute fade is much gentler.
- Stereo mode sends independent noise to each ear, which sounds wider and more natural on headphones than mono.
Frequently asked questions
What is pink noise?
Pink noise is random noise whose power falls by 3 dB for every doubling of frequency, so its power spectral density is proportional to 1/f. Because each octave covers twice as many frequencies as the one below, the result is equal energy in every octave, which our hearing perceives as balanced. It sounds deeper and softer than white noise, like steady rain or wind.
What is the difference between pink noise and white noise?
White noise has equal power at every frequency, so each higher octave holds twice the energy of the one below and it sounds bright and hissy. Pink noise has equal power per octave and sounds fuller and less harsh. Brown noise drops 6 dB per octave and is deeper still.
How is the pink noise generated?
White random numbers are filtered in real time inside an AudioWorklet. The default Paul Kellet method sums seven one-pole low-pass filters to approximate a −3 dB per octave slope within about ±0.05 dB above 9 Hz. The Voss-McCartney method adds 16 random values that are refreshed at rates halving from row to row. Both are normalised so the level slider reads true dBFS RMS.
How do I calibrate speakers with pink noise?
Use a sound level meter set to C weighting and slow response at your listening position. Play −20 dBFS pink noise through one speaker at a time, band-limited to 500 Hz–2 kHz for main speakers, and adjust each channel's level on your receiver until the meter shows the same target. Cinemas use 85 dBC per channel (SMPTE RP 200); 75 to 79 dBC is common in home theaters. Use the 20–80 Hz band for the subwoofer and set it by ear or to the same reading.
Is pink noise good for sleep?
Many people find steady pink noise masks traffic, snoring and other sudden sounds, and some small studies have reported effects on deep sleep, but the evidence is limited. Keep the volume moderate, well below the level of normal conversation, and use the sleep timer if you prefer silence later in the night.
Does the noise loop or repeat?
No. In modern browsers each sample is generated on the fly, so the noise never repeats. Only very old browsers without AudioWorklet support fall back to a 20-second pre-generated buffer that loops.
What does dBFS RMS mean here?
dBFS is decibels relative to digital full scale. The meter shows the root-mean-square level of the output, where a full-scale square wave would read 0 dB and a full-scale sine wave −3 dB. −20 dBFS RMS leaves about 6 to 8 dB of headroom above the highest noise peaks, which is why it is the standard calibration level.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.