AudioContext.createConvolver

Syntax

var audioCtx = new AudioContext();
var convolver = audioCtx.createConvolver();

Returns

A ConvolverNode.

Example

The following example shows basic usage of an AudioContext to create a convolver node. The basic premise is that you create an AudioBuffer containing a sound sample to be used as an ambience to shape the convolution (called the impulse response,) and apply that to the convolver. The example below uses a short sample of a concert hall crowd, so the reverb effect applied is really deep and echoey.

For applied examples/information, check out our Voice-change-O-matic demo (see app.js for relevant code).

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var convolver = audioCtx.createConvolver();

  ...

// grab audio track via XHR for convolver node

var soundSource, concertHallBuffer;

ajaxRequest = new XMLHttpRequest();
ajaxRequest.open('GET', 'concert-crowd.ogg', true);
ajaxRequest.responseType = 'arraybuffer';

ajaxRequest.onload = function() {
  var audioData = ajaxRequest.response;
  audioCtx.decodeAudioData(audioData, function(buffer) {
      concertHallBuffer = buffer;
      soundSource = audioCtx.createBufferSource();
      soundSource.buffer = concertHallBuffer;
    }, function(e){"Error with decoding audio data" + e.err});
}

ajaxRequest.send();

  ...

convolver.buffer = concertHallBuffer;

Specifications

Specification	Status	Comment
Web Audio API The definition of 'createConvolver()' in that specification.	Working Draft

Browser compatibility

See also

• Using the Web Audio API