Try it

Move the levels and listen. The chart is worked out by the very code that makes the sound.

LowHigh

Listen to this mix

The seven colors

• White noise

  Equal energy at every pitch. Each sample is a fresh random number, so nothing links one moment to the next. It is the brightest of the plain colors and the best at covering sudden sounds.

• Pink noise

  Energy falls 3 dB with every octave, so every octave carries the same amount. The engine bends white noise through six one-pole filters (Paul Kellet’s refined method), which holds the slope steady from about 20 Hz to 10 kHz. Many people hear it as the most natural.

• Brown noise

  Energy falls 6 dB per octave. The engine keeps a running total of the white noise and lets a little of it leak away each step, so it never drifts off: x = (x + 0.02 × white) ÷ 1.02. A deep, soft rumble.

• Gray noise

  White noise bent to match how ears hear. A low shelf adds 9 dB below 250 Hz, a dip takes 9 dB out around 3.2 kHz, and a high shelf adds 4 dB above 9 kHz: three biquad filters from the RBJ cookbook.

• Green noise

  The middle of the spectrum, where voices and rain live: a 200 Hz high-pass followed by a 1.2 kHz low-pass, both second order. Like a forest with its sharp edges taken off.

• Blue noise

  Energy rises 3 dB per octave, the opposite of pink. The engine takes the difference between one pink sample and the next. Bright and hissy, best used in small amounts.

• Violet noise

  Energy rises 6 dB per octave: the difference between one white sample and the next. The brightest color here, a fine mist of high pitches.

Tone, waves and the soft clip

The tone knob is a one-pole low-pass that glides from 400 Hz (dark) to fully open. Waves slowly swell and ease the level over ten seconds, up to 70 percent deep. A soft clip bends anything above 0.8 so that nothing ever clips hard, and the master level glides rather than jumps.

Use it

The engine is a single file with no dependencies, offered under the Apache-2.0 license as the @noisez/noise package: the code only, with none of the app’s sounds or artwork. It runs as an AudioWorklet, directly in Node, or through a ScriptProcessor where worklets are missing.

const NoiseDSP = require('@noisez/noise');
const dsp = new NoiseDSP(48000);
// gains: [white, pink, brown, grey, green, blue, violet]
dsp.setParameters({ gains: [0, 0, 0.3, 0, 0, 0, 0], toneCoefficient: 1, waves: 0 });
dsp.setMaster(0.5);
const left = new Float32Array(128), right = new Float32Array(128);
dsp.render(128, left, right);   // false when it rendered silence

// In a browser, as an AudioWorklet:
await audioContext.audioWorklet.addModule('/node_modules/@noisez/noise/noise-dsp.js');
const node = new AudioWorkletNode(audioContext, 'noisez-noise', { outputChannelCount: [2] });
node.port.postMessage({ master: 0.5, params: { gains: [0, 0, 0.3, 0, 0, 0, 0], toneCoefficient: 1, waves: 0 } });

To put the player on a page without writing any code, make an embed.

How is it made?

Every noise color is generated live, from a few lines of open code. Move the sliders and hear what each one does.

Get NoiseZ on the App StorePlayer