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 Voice-change-O-matic demo (see app.js for relevant code).

Note: Distortion curves are not the easiest thing to work out, and you will probably need to look around to find such algorithms. 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 API
The definition of 'curve' in that specification.
Working Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 10.0webkit (Yes) 25.0 (25.0)  No support 15.0webkit
22 (unprefixed)
6.0webkit
Feature Android Edge Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support ? (Yes) 26.0 1.2 ? ? ? 33.0

See also

Document Tags and Contributors

 Contributors to this page: erikadoyle, fscholz, chrisdavidmills
 Last updated by: erikadoyle,