How to use the noise generator
- Turn your device volume down, then press Play. The noise fades in over one second.
- Pick a preset or move the color sliders. Balanced mixes pink and brown noise; Deep leans on brown; Bright adds white, blue and a little violet. Any change glides in, with no clicks.
- Open Spectrum to see the mix. The readout shows the measured slope, such as “−3.0 dB per octave · pink-like”.
- Set a sleep timer from 15 minutes to 8 hours, with a 10, 20 or 30 second fade-out.
- Lock your phone or press ◐ Dim screen. The noise keeps playing.
- Copy the link to share your mix. It keeps the color levels, never the volume.
With the tool focused, Space or K plays and pauses, ↑ and ↓ change the volume, D dims the screen and T steps through the timer.
Noise colors explained
Noise colors describe how the sound’s energy is spread from low to high frequencies. The slope is measured in decibels per octave.
| Color | Slope | Often compared to | Common use | Page |
|---|---|---|---|---|
| White | 0 dB per octave | TV static, a hiss | Masking voices | white noise |
| Pink | −3 dB per octave | Steady rain | Sleep, speaker checks | pink noise generator |
| Brown | −6 dB per octave | A distant waterfall, a deep rumble | Masking low sounds | brown noise generator |
| Green | A bump near 500 Hz | Wind, the middle of the range | Background sound | green noise |
| Blue | +3 dB per octave | A hiss with more sparkle | Audio tests | — |
| Violet | +6 dB per octave | A very bright hiss | Dithering, tests | — |
White noise has equal energy at every frequency, so the top octave, 10 to 20 kHz, holds as much energy as everything below it. That’s why it sounds hissy. Pink noise gives each octave the same energy instead: across 20 Hz to 20 kHz, each of the 10 octaves carries about 10% of the total.
Brown noise is named after the botanist Robert Brown and the random motion he described, not after the color. Green noise has no single standard; here it’s pink noise focused around 500 Hz. Blue and violet noise mostly serve audio work such as dithering and tests.
How the noise generator works
An audio noise generator makes random numbers at the sample rate of your device, usually 44,100 or 48,000 per second. That stream is white noise. Filters shape it into the other colors: they soften the highs for pink and brown, or lift them for blue and violet.
This page generates the noise live, in a small audio program that runs beside the page. Nothing repeats, so there’s no loop to hear, and no data is used after the page has loaded. If your browser can’t run that program, the page falls back to a 10-second loop with a smooth seam.
The spectrum view shows the generated signal, not what your speakers play. Phone and laptop speakers roll off below about 100 to 200 Hz, so brown noise sounds thinner on them than on headphones. To see what a microphone picks up instead, use the spectrum analyzer.
Using a noise generator for sleep or focus
Many people use steady noise to mask sounds that change, such as traffic, voices or a door slamming down the hall. A constant sound makes sudden ones less noticeable, which is why fans and air conditioners have long been popular at night.
Keep the level low. If you’d have to raise your voice to talk over the noise, it’s too loud. For sleep, put the phone or speaker across the room rather than next to your head, and use the timer if you only need sound while you fall asleep.
For work or study, try a mix with less hiss, such as Balanced or Deep, and wear headphones in a shared space. Results vary from person to person, so trust your own comfort over any rule. If the sound seems wrong on one side, check your speakers with the speaker test.
Playing noise on a phone
Open the page, press Play, then lock the screen. On most phones the noise keeps playing, and the timer still fades it out on time because it runs on the audio clock rather than on page timers.
On an iPhone, check the Ring/Silent switch if you hear nothing, and close other apps that play audio. Some phones close background tabs when memory or battery runs low, so plug the phone in for a full night.
Battery use is small but real: a phone has to keep its audio hardware awake. Lowering the screen brightness, or using ◐ Dim screen, saves more power than anything else you can do on this page.