files/en-us/web/api/baseaudiocontext/createwaveshaper/index.md
{{ APIRef("Web Audio API") }}
The createWaveShaper() method of the {{ domxref("BaseAudioContext") }}
interface creates a {{ domxref("WaveShaperNode") }}, which represents a non-linear
distortion. It is used to apply distortion effects to your audio.
[!NOTE] The {{domxref("WaveShaperNode.WaveShaperNode", "WaveShaperNode()")}} constructor is the recommended way to create a {{domxref("WaveShaperNode")}}; see Creating an AudioNode.
createWaveShaper()
None.
A {{domxref("WaveShaperNode")}}.
The following example shows basic usage of an AudioContext to create a wave shaper node. For more complete 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.
const audioCtx = new AudioContext();
const distortion = audioCtx.createWaveShaper();
// …
function makeDistortionCurve(amount) {
const k = typeof amount === "number" ? amount : 50;
const numSamples = 44100;
const curve = new Float32Array(numSamples);
const deg = Math.PI / 180;
for (let i = 0; i < numSamples; i++) {
const x = (i * 2) / numSamples - 1;
curve[i] = ((3 + k) * x * 20 * deg) / (Math.PI + k * Math.abs(x));
}
return curve;
}
// …
distortion.curve = makeDistortionCurve(400);
distortion.oversample = "4x";
{{Specifications}}
{{Compat}}