ConvolverNode: normalize property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.

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.

Value

A boolean.

Examples

Switching normalization off

The following example creates a convolver node and assigns it an AudioBuffer. Before assigning the audio buffer, it sets normalize to false.

js
const audioCtx = new AudioContext();
// ...

const convolver = audioCtx.createConvolver();
// ...

// Grab audio track via fetch() for convolver node
try {
  const response = await fetch(
    "https://mdn.github.io/voice-change-o-matic/audio/concert-crowd.ogg",
  );
  const arrayBuffer = await response.arrayBuffer();
  const decodedAudio = await audioCtx.decodeAudioData(arrayBuffer);
  convolver.normalize = false; // must be set before the buffer, to take effect
  convolver.buffer = decodedAudio;
} catch (error) {
  console.error(
    `Unable to fetch the audio file: ${name} Error: ${err.message}`,
  );
}

Specifications

Specification
Web Audio API
# dom-convolvernode-normalize

Browser compatibility

BCD tables only load in the browser

See also