The frequency property of the OscillatorNode interface is an a-rate AudioParam representing the frequency of oscillation in hertz.
Note: Though the AudioParam returned is read-only, the value it represents is not.
An a-rate AudioParam.
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).
// create web audio api context
const audioCtx = new AudioContext();
// create Oscillator node
const oscillator = audioCtx.createOscillator();
oscillator.type = "square";
oscillator.frequency.setValueAtTime(440, audioCtx.currentTime); // value in hertz
oscillator.start();