The OscillatorNode interface represents a periodic waveform, such as a sine wave. It is an AudioScheduledSourceNode audio-processing module that causes a specified frequency of a given wave to be created—in effect, a constant tone.

An OscillatorNode is created using the BaseAudioContext.createOscillator() method. It always has exactly one output and no inputs. Its basic property defaults (see AudioNode for definitions) are:

Number of inputs 0
Number of outputs 1
Channel count mode max
Channel count 2 (not used in the default count mode)
Channel interpretation speakers

Constructor

OscillatorNode()
Creates a new instance of an OscillatorNode object, optionally providing an object specifying default values for the node's properties.  If the default values are acceptable, you can simply call the BaseAudioContext.createOscillator() factory method.

Properties

Inherits properties from its parent, AudioScheduledSourceNode, and adds the following properties:

OscillatorNode.frequency
An a-rate AudioParam representing the frequency of oscillation in hertz (though the AudioParam returned is read-only, the value it represents is not). The default value is 440 Hz (a standard middle-A note).
OscillatorNode.detune
An a-rate AudioParam representing detuning of oscillation in cents (though the AudioParam returned is read-only, the value it represents is not). The default value is 0.
OscillatorNode.type
A string which specifies the shape of waveform to play; this can be one of a number of standard values, or custom to use a PeriodicWave to describe a custom waveform. Different waves will produce different tones. Standard values are "sine", "square", "sawtooth", "triangle" and "custom". The default is "sine".

Event handlers

OscillatorNode.onended
Sets the event handler for the ended event, which fires when the tone has stopped playing.

Methods

Inherits methods from its parent, AudioScheduledSourceNode, and adds the following:

OscillatorNode.setPeriodicWave()
Sets a PeriodicWave which describes a periodic waveform to be used instead of one of the standard waveforms; calling this sets the type to custom. This replaces the now-obsolete OscillatorNode.setWaveTable() method.
OscillatorNode.start()
Specifies the exact time to start playing the tone.
OscillatorNode.stop()
Specifies the time to stop playing the tone.

Examples

The following example shows basic usage of an AudioContext to create an oscillator node and to start playing a tone on it. For an applied example, check out our Violent Theremin demo (see app.js for relevant code).

// create web audio api context
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();

// create Oscillator node
var oscillator = audioCtx.createOscillator();

oscillator.type = 'square';
oscillator.frequency.setValueAtTime(440, audioCtx.currentTime); // value in hertz
oscillator.connect(audioCtx.destination);
oscillator.start();

Specifications

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support14 Yes25 No156
OscillatorNode() constructor551 ?53 No42 ?
detune141225 No156
frequency141225 No156
onended141225 No156
type141225 No156
setPeriodicWave141225 No156
start1412252 No156
stop1412252 No156
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support1414 Yes2615 ? Yes
OscillatorNode() constructor551551 ?5342 ?6.0
detune Yes14 Yes2615 ? Yes
frequency Yes14 Yes2615 ? Yes
onended Yes14 Yes2615 ? Yes
type Yes14 Yes2615 ? Yes
setPeriodicWave1414 Yes2615 ? Yes
start1414 Yes26215 ? Yes
stop1414 Yes26215 ? Yes

1. Before Chrome 59, the default values were not supported.

2. Before Firefox 30, the when parameter was not optional.

See also

Document Tags and Contributors

Last updated by: MysteryPancake,