Web/API/WaveShaperNode/curve

The curve property of the WaveShaperNode interface is a Float32Array of numbers describing the distortion to apply.

The mid-element of the array is applied to any signal value of 0, the first one to signal values of -1, and the last to signal values of 1; values lower than -1 or greater than 1 are treated like -1 or 1 respectively.

If necessary, intermediate values of the distortion curve are linearly interpolated.

Note: The array can be a null value: in that case, no distortion is applied to the input signal.

Syntax

var audioCtx = new AudioContext();
var distortion = audioCtx.createWaveShaper();
distortion.curve = myCurveDataArray; // myCurveDataArray is a Float32Array

Value

A Float32Array.

Example

The following example shows basic usage of an AudioContext to create a wave shaper node. For applied examples/information, check out our [[../../../../../../../mdn.github.io/voice-change-o-matic/index|Voice-change-O-matic]] [[../../../../../../../mdn.github.io/voice-change-o-matic/index|demo]] (see app.js for relevant code).

Note: Sigmoid functions are commonly used for distortion curves because of their natural properties. Their S-shape, for instance, helps create a smoother sounding result. We found the below distortion curve code on Stack Overflow.

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var distortion = audioCtx.createWaveShaper();

  ...

function makeDistortionCurve(amount) {
  var k = typeof amount === 'number' ? amount : 50,
    n_samples = 44100,
    curve = new Float32Array(n_samples),
    deg = Math.PI / 180,
    i = 0,
    x;
  for ( ; i < n_samples; ++i ) {
    x = i * 2 / n_samples - 1;
    curve[i] = ( 3 + k ) * x * 20 * deg / ( Math.PI + k * Math.abs(x) );
  }
  return curve;
};

  ...

distortion.curve = makeDistortionCurve(400);
distortion.oversample = '4x';

Specifications

Specification	Status	Comment
Web Audio APIThe definition of 'curve' in that specification.	Working Draft

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`curve`	Chrome Full support 14	Edge Full support 12	Firefox Full support 25	IE No support No	Opera Full support 15	Safari Full support 6	WebView Android Full support Yes	Chrome Android Full support 18	Firefox Android Full support 26	Opera Android Full support 14	Safari iOS Full support Yes	Samsung Internet Android Full support 1.0

Legend

Full support: Full support
No support: No support