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: 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 API The definition of 'curve' in that specification. |
Working Draft |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
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