Web Audio: Recreating an oscillator after timed stop

Question

I want to sound an oscillator note for 2 seconds. But the next time, even after recreating a new oscillator, no sound is played:

        oscillator = context.createOscillator();

        oscillator.frequency.value = 440;         
        oscillator.type = oscillator.SINE;        

        oscillator.connect(context.destination);          

        oscillator.start(0);
        oscillator.stop(2);

If I omit stop(2) and instead use setTimeout() to oscillator.stop() in a function, it works. I have read that the node should be disconnected, but disconnect() does not accept a time as argument, only an output index. Any pointer for the solution?

score 2 · Accepted Answer · answered Feb 19 '14 at 18:35

The "when" parameter to start and stop is based on AudioContext.currentTime. Zero means "now" - currentTime also starts at zero when the AudioContext is created. So when you say ".start(0); .stop(2);" the second time around, the "stop" is already in the past (check AudioContext.currentTime - it's already >2), so the start never causes any effect.

Instead of what you're currently doing, do:

    oscillator.start(context.currentTime);
    oscillator.stop(context.currentTime+2);

Thanks for clearing that up, now the concept is even clearer to me. — Robse, Feb 20 '14 at 16:48

Web Audio: Recreating an oscillator after timed stop

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