ConvolverNode.normalize

The normalize property of the ConvolverNode interface is a boolean that controls whether the impulse response from the buffer will be scaled by an equal-power normalization when the buffer attribute is set, or not.

Its default value is true in order to achieve a more uniform output level from the convolver, when loaded with diverse impulse responses. If normalize is set to false, then the convolution will be rendered with no pre-processing/scaling of the impulse response. Changes to this value do not take effect until the next time the buffer attribute is set.

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

A boolean.

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.normalize = false; // must be set before the buffer, to take effect
convolver.buffer = concertHallBuffer;

• Using the Web Audio API