DelayNode - Web APIs 编辑

The DelayNode interface represents a delay-line; an AudioNode audio-processing module that causes a delay between the arrival of an input data and its propagation to the output. A DelayNode always has exactly one input and one output, both with the same amount of channels.

When creating a graph that has a cycle, it is mandatory to have at least one DelayNode in the cycle, or the nodes taking part in the cycle will be muted.

Constructor

DelayNode()

Creates a new instance of an DelayNode object instance. Alternatively, you can use the BaseAudioContext.createDelay() factory method.

Properties

Inherits properties from its parent, AudioNode.

DelayNode.delayTime Read only

Is an a-rate AudioParam representing the amount of delay to apply, specified in seconds.

Methods

No specific methods; inherits methods from its parent, AudioNode.

Example

We have created a simple example that allows you to play three different samples on a constant loop — see create-delay (you can also view the source code). If you just press the play buttons, the loops will start immediately; if you slide the sliders up to the right, then press the play buttons, a delay will be introduced, so the looping sounds don't start playing for a short amount of time.

var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext();

var synthDelay = audioCtx.createDelay(5.0);

  ...

var synthSource;

playSynth.onclick = function() {
  synthSource = audioCtx.createBufferSource();
  synthSource.buffer = buffers[2];
  synthSource.loop = true;
  synthSource.start();
  synthSource.connect(synthDelay);
  synthDelay.connect(destination);
  this.setAttribute('disabled', 'disabled');
}

stopSynth.onclick = function() {
  synthSource.disconnect(synthDelay);
  synthDelay.disconnect(destination);
  synthSource.stop();
  playSynth.removeAttribute('disabled');
}

...

var delay1;
rangeSynth.oninput = function() {
  delay1 = rangeSynth.value;
  synthDelay.delayTime.setValueAtTime(delay1, audioCtx.currentTime);
}

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using the Web Audio API