BaseAudioContext: createGain() method
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 createGain() method of the BaseAudioContext interface creates a GainNode, which can be used to control the overall gain (or volume) of the audio graph.
Note: The GainNode() constructor is the recommended way to create a GainNode; see Creating an AudioNode.
Syntax
createGain() Parameters
None.
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.
Examples
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> const audioCtx = new AudioContext(); const gainNode = audioCtx.createGain(); const mute = document.querySelector(".mute"); let source; if (navigator.mediaDevices.getUserMedia) { navigator.mediaDevices.getUserMedia( // constraints - only audio needed for this app { audio: true, }, // Success callback (stream) => { source = audioCtx.createMediaStreamSource(stream); }, // Error callback (err) => { console.error(`The following gUM error occurred: ${err}`); }, ); } else { console.error("getUserMedia not supported on your browser!"); } source.connect(gainNode); gainNode.connect(audioCtx.destination); // … mute.onclick = () => { 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.textContent = "Unmute"; } else { gainNode.gain.setValueAtTime(1, audioCtx.currentTime); mute.id = ""; mute.textContent = "Mute"; } }; Specifications
| Specification |
|---|
| Web Audio API # dom-baseaudiocontext-creategain |