AudioContext()

The AudioContext() constructor creates a new AudioContext object which represents an audio-processing graph, built from audio modules linked together, each represented by an AudioNode.

Syntax

var audioCtx = new AudioContext();
var audioCtx = new AudioContext(options);

Parameters

options Optional
An object based on the AudioContextOptions dictionary that contains zero or more optional properties to configure the new context. Available properties are as follows:
latencyHint Optional
The type of playback that the context will be used for, as a value from the AudioContextLatencyCategory enum or a double-precision floating-point value indicating the preferred maximum latency of the context in seconds. The user agent may or may not choose to meet this request; check the value of AudioContext.baseLatency to determine the true latency after creating the context.
sampleRate Optional
The sampleRate to be used by the AudioContext, specified in samples per second. The value may be any value supported by AudioBuffer. If not specified, the preferred sample rate for the context's output device is used by default.

Return value

The newly constructed AudioContext instance.

Exceptions

NotSupportedError
The specified sampleRate isn't supported by the context.

Usage notes

The specification doesn't go into a lot of detail about things like how many audio contexts a user agent should support, or minimum or maximum latency requirements (if any), so these details can vary from browser to browser. Be sure to check the values if they matter to you.

In particular, the specification doesn't indicate a maximum or minimum number of audio contexts that must be able to be open at the same time, so this is left up to the browser implementations to decide.

Google Chrome

Per-tab audio context limitation in Chrome

Prior to version 66 Google Chrome only supported up to six audio contexts per tab at a time.

Non-standard exceptions in Chrome

If the value of the latencyHint property isn't valid, Chrome throws a TypeError exception with the message "The provided value '...' is not a valid enum value of type AudioContextLatencyCategory".

Example

This example creates a new AudioContext for interactive audio (optimizing for latency) and a sample rate of 44.1kHz.

var AudioContext = window.AudioContext || window.webkitAudioContext;

var audioCtx = new AudioContext({
  latencyHint: 'interactive',
  sampleRate: 44100,
});

Specifications

Specification Status Comment
Web Audio API
The definition of 'AudioContext()' in that specification.
Working Draft Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
AudioContext() constructorChrome Full support 55
Notes
Full support 55
Notes
Notes Each tab is limited to 6 audio contexts in Chrome; attempting to create more will throw a DOMException. For details see Per-tab audio context limitation in Chrome.
Notes If latencyHint isn't valid, Chrome throws a TypeError exception. See Non-standard exceptions in Chrome for details.
Edge Full support ≤18Firefox Full support 25IE No support NoOpera Full support 42Safari Full support Yes
Prefixed
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Full support 55Chrome Android Full support 55
Notes
Full support 55
Notes
Notes Each tab is limited to 6 audio contexts in Chrome; attempting to create more will throw a DOMException. For details see Per-tab audio context limitation in Chrome.
Notes If latencyHint isn't valid, Chrome throws a TypeError exception. See Non-standard exceptions in Chrome for details.
Firefox Android Full support 26Opera Android Full support 42Safari iOS Full support Yes
Prefixed
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Samsung Internet Android Full support 6.0
Notes
Full support 6.0
Notes
Notes Each tab is limited to 6 audio contexts in Samsung Internet; attempting to create more will throw a DOMException. For details see Per-tab audio context limitation in Samsung Internet.
Notes If latencyHint isn't valid, Samsung Internet throws a TypeError exception. See Non-standard exceptions in Samsung Internet for details.
latencyHint option
Experimental
Chrome Full support 60Edge Full support 79Firefox No support NoIE No support NoOpera Full support 47Safari ? WebView Android Full support 60Chrome Android Full support 60Firefox Android No support NoOpera Android Full support 44Safari iOS ? Samsung Internet Android Full support 8.0
sampleRate option
Experimental
Chrome Full support 74Edge Full support 79Firefox No support NoIE No support NoOpera No support NoSafari Full support YesWebView Android Full support 74Chrome Android Full support 74Firefox Android ? Opera Android ? Safari iOS Full support YesSamsung Internet Android Full support 11.0

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
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