The AudioNode interface is a generic interface for representing an audio processing module like an audio source (e.g. an HTML <audio> or <video> element, an OscillatorNode, etc.), the audio destination, intermediate processing module (e.g. a filter like BiquadFilterNode or ConvolverNode), or volume control (like GainNode).

AudioNodes participating in an AudioContext create a audio routing graph.

An AudioNode has inputs and outputs, each with a given amount of channels. An AudioNode with zero inputs and one or multiple outputs is called a source node. The exact processing done varies from one AudioNode to another but, in general, a node reads its inputs, does some audio-related processing, and generates new values for its outputs, or simply lets the audio pass through (for example in the AnalyserNode, where the result of the processing is accessed separately).

Different nodes can be linked together to build a processing graph. Such a graph is contained in an AudioContext. Each AudioNode participates in exactly one such context. In general, processing nodes inherit the properties and methods of AudioNode, but also define their own functionality on top. See the individual node pages for more details, as listed on the Web Audio API homepage.

Note: An AudioNode can be target of events, therefore it implements the EventTarget interface.

Properties

AudioNode.context Read only
Returns the associated AudioContext, that is the object representing the processing graph the node is participating in.
AudioNode.numberOfInputs Read only
Returns the number of inputs feeding the node. Source nodes are defined as nodes having a numberOfInputs property with a value of 0.
AudioNode.numberOfOutputs Read only
Returns the number of outputs coming out of the node. Destination nodes — like AudioDestinationNode — have a value of 0 for this attribute.
AudioNode.channelCount
Represents an integer used to determine how many channels are used when up-mixing and down-mixing connections to any inputs to the node. Its usage and precise definition depend on the value of AudioNode.channelCountMode.
AudioNode.channelCountMode
Represents an enumerated value describing the way channels must be matched between the node's inputs and outputs.
AudioNode.channelInterpretation
Represents an enumerated value describing the meaning of the channels. This interpretation will define how audio up-mixing and down-mixing will happen.
The possible values are "speakers" or "discrete".

Methods

Also implements methods from the interface EventTarget.

AudioNode.connect()
Allows us to connect the output of this node to be input into another node, either as audio data or as the value of an AudioParam.
AudioNode.disconnect()
Allows us to disconnect the current node from another one it is already connected to.

Example

This simple snippet of code shows the creation of some audio nodes, and how the AudioNode properties and methods can be used. You can find examples of such usage on any of the examples linked to on the Web Audio API landing page (for example Violent Theremin.)

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

var audioCtx = new AudioContext();

var oscillator = audioCtx.createOscillator();
var gainNode = audioCtx.createGain();

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

oscillator.context;
oscillator.numberOfInputs;
oscillator.numberOfOutputs;
oscillator.channelCount;

Specifications

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support14 Yes25 No156
channelCount14 Yes25 No156
channelCountMode14 Yes25 No156
channelInterpretation14 Yes25 No156
context14 Yes25 No156
numberOfInputs14 Yes25 No156
numberOfOutputs14 Yes25 No156
connect14 Yes25 No156
disconnect14 Yes25 No156
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support Yes14 Yes26 No15 ?
channelCount Yes14 Yes26 No15 ?
channelCountMode Yes14 Yes26 No15 ?
channelInterpretation Yes14 Yes26 No15 ?
context Yes14 Yes26 No15 ?
numberOfInputs Yes14 Yes26 No15 ?
numberOfOutputs Yes14 Yes26 No15 ?
connect Yes14 Yes26 No15 ?
disconnect Yes14 Yes26 No15 ?

See also

Document Tags and Contributors

 Last updated by: fscholz,