OscillatorNode: type property
The type
property of the OscillatorNode
interface specifies what shape of waveform the
oscillator will output. There are several common waveforms available, as well as an
option to specify a custom waveform shape. The shape of the waveform will affect the
tone that is produced.
Value
A string specifying the shape of oscillator wave. The different available values are:
sine
-
A sine wave. This is the default value.
square
-
A square wave with a duty cycle of 0.5; that is, the signal is "high" for half of each period.
sawtooth
triangle
custom
-
A custom waveform. You never set
type
tocustom
manually; instead, use thesetPeriodicWave()
method to provide the data representing the waveform. Doing so automatically sets thetype
tocustom
.
Exceptions
InvalidStateError
DOMException
-
Thrown if the value
custom
was specified. To set a custom waveform, just callsetPeriodicWave()
. Doing so automatically sets the type for you.
Examples
The following example shows basic usage of an AudioContext
to create
an oscillator node. For an applied example, check out our Violent Theremin demo (see app.js for relevant code).
js
// create web audio api context
const audioCtx = new (window.AudioContext || window.webkitAudioContext)();
// create Oscillator node
const oscillator = audioCtx.createOscillator();
oscillator.type = "square";
oscillator.frequency.setValueAtTime(440, audioCtx.currentTime); // value in hertz
oscillator.start();
Specifications
Specification |
---|
Web Audio API # dom-oscillatornode-type |
Browser compatibility
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