The createGain()
method of the BaseAudioContext
interface creates a GainNode
, which can be used to control the overall gain (or volume) of the audio graph.
Syntax
var gainNode = AudioContext.createGain();
Return value
A GainNode
which takes as input one or more audio sources and outputs audio whose volume has been adjusted in gain (volume) to a level specified by the node's GainNode.gain
a-rate parameter.
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 [[../../../../../../../mdn.github.io/voice-change-o-matic/index|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 APIThe definition of 'createGain()' in that specification. | Working Draft |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
createGain
|
Chrome Full support 10 Full support 10 Prefixed' Implemented with the vendor prefix: webkit |
Edge
Full support ≤18 |
Firefox Full support 53 Full support 53 Notes' Originally implemented on |
IE
No support No |
Opera Full support 22 Full support 22 Full support 15 Prefixed' Implemented with the vendor prefix: webkit |
Safari Full support 6 Full support 6 Prefixed' Implemented with the vendor prefix: webkit |
WebView Android
Full support Yes |
Chrome Android
Full support 33 |
Firefox Android Full support 53 Full support 53 Notes' Originally implemented on |
Opera Android Full support 22 Full support 22 Full support 14 Prefixed' Implemented with the vendor prefix: webkit |
Safari iOS Full support 6 Full support 6 Prefixed' Implemented with the vendor prefix: webkit |
Samsung Internet Android
Full support 2.0 |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.'
- See implementation notes.
- Requires a vendor prefix or different name for use.'
- Requires a vendor prefix or different name for use.
See also
BaseAudioContext.createGain() by Mozilla Contributors is licensed under CC-BY-SA 2.5.