GainNode

The GainNode interface represents a change in volume. It is an AudioNode audio-processing module that causes a given gain to be applied to the input data before its propagation to the output. A GainNode always has exactly one input and one output, both with the same number of channels.

The gain is a unitless value, changing with time, that is multiplied to each corresponding sample of all input channels. If modified, the new gain is instantly applied, causing unaesthetic 'clicks' in the resulting audio. To prevent this from happening, never change the value directly but use the exponential interpolation methods on the AudioParam interface.

The GainNode is increasing the gain of the output.

Number of inputs 1
Number of outputs 1
Channel count mode "max"
Channel count 2 (not used in the default count mode)
Channel interpretation "speakers"

Constructor

GainNode()
Creates a new instance of a GainNode object. You shouldn't manually create a gain node; instead, use the method AudioContext.createGain().

Properties

Inherits properties from its parent, AudioNode.

GainNode.gain Read only
Is an a-rate AudioParam representing the amount of gain to apply. You have to set AudioParam.value or use the methods of AudioParam to change the effect of gain.

Methods

No specific method; inherits methods from its parent, AudioNode.

Example

The following example shows basic usage of an AudioContext to create a GainNode, which is then used to mute and unmute the audio when a Mute button is clicked by changing the gain property value.

The below snippet wouldn't work as is — for a complete working example, check out our Voice-change-O-matic demo (view source.)

<div>
  <button class="mute">Mute button</button>
</div>
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var gainNode = audioCtx.createGain();
var mute = document.querySelector('.mute');
var source;

if (navigator.mediaDevices.getUserMedia) {
 navigator.mediaDevices.getUserMedia (
   // constraints - only audio needed for this app
   {
     audio: true
   },

   // Success callback
   function(stream) {
     source = audioCtx.createMediaStreamSource(stream);

   },

   // Error callback
   function(err) {
     console.log('The following gUM error occured: ' + err);
   }
  );
} else {
   console.log('getUserMedia not supported on your browser!');
}

source.connect(gainNode);
gainNode.connect(audioCtx.destination);

  ...

mute.onclick = voiceMute;

function voiceMute() {
  if(mute.id == "") {
    // 0 means mute. If you still hear something, make sure you haven't
    // connected your source into the output in addition to using the GainNode.
    gainNode.gain.setValueAtTime(0, audioCtx.currentTime);
    mute.id = "activated";
    mute.innerHTML = "Unmute";
  } else {
    gainNode.gain.setValueAtTime(1, audioCtx.currentTime);
    mute.id = "";
    mute.innerHTML = "Mute";
  }
}

Specifications

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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
GainNodeChrome Full support 14Edge Full support ≤18Firefox Full support 25IE No support NoOpera Full support 15Safari Full support 6WebView Android Full support YesChrome Android Full support 18Firefox Android Full support 26Opera Android Full support 14Safari iOS Full support YesSamsung Internet Android Full support 1.0
GainNode() constructorChrome Full support 55
Notes
Full support 55
Notes
Notes Before Chrome 59, the default values were not supported.
Edge Full support ≤79Firefox Full support 53IE No support NoOpera Full support 42Safari ? WebView Android Full support 55
Notes
Full support 55
Notes
Notes Before Chrome 59, the default values were not supported.
Chrome Android Full support 55
Notes
Full support 55
Notes
Notes Before Chrome 59, the default values were not supported.
Firefox Android Full support 53Opera Android Full support 42Safari iOS ? Samsung Internet Android Full support 6.0
Notes
Full support 6.0
Notes
Notes Before Samsung Internet 7.0, the default values were not supported.
gainChrome Full support 14Edge Full support 12Firefox Full support 25IE No support NoOpera Full support 15Safari Full support 6WebView Android Full support YesChrome Android Full support 18Firefox Android Full support 26Opera Android Full support 14Safari iOS Full support YesSamsung Internet Android Full support 1.0

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown
See implementation notes.
See implementation notes.

See also