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The threshold
property of the DynamicCompressorNode
interface is a k-rate AudioParam
representing the decibel value above which the compression will start taking effect.
The threshold
property's default value is -24
and it can be set between -100
and 0
.
Syntax
var audioCtx = new AudioContext(); var compressor = audioCtx.createDynamicsCompressor(); compressor.threshold.value = -50;
Value
An AudioParam
.
Note: Though the AudioParam
returned is read-only, the value it represents is not.
Example
The below code demonstrates a simple usage of createDynamicsCompressor()
to add compression to an audio track. For a more complete example, have a look at our basic Compressor example (view the source code).
// Create a MediaElementAudioSourceNode // Feed the HTMLMediaElement into it var source = audioCtx.createMediaElementSource(myAudio); // Create a compressor node var compressor = audioCtx.createDynamicsCompressor(); compressor.threshold.value = -50; compressor.knee.value = 40; compressor.ratio.value = 12; compressor.reduction.value = -20; compressor.attack.value = 0; compressor.release.value = 0.25; // connect the AudioBufferSourceNode to the destination source.connect(audioCtx.destination); button.onclick = function() { var active = button.getAttribute('data-active'); if(active == 'false') { button.setAttribute('data-active', 'true'); button.innerHTML = 'Remove compression'; source.disconnect(audioCtx.destination); source.connect(compressor); compressor.connect(audioCtx.destination); } else if(active == 'true') { button.setAttribute('data-active', 'false'); button.innerHTML = 'Add compression'; source.disconnect(compressor); compressor.disconnect(audioCtx.destination); source.connect(audioCtx.destination); } }
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'threshold' in that specification. |
Working Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 10.0webkit | 25.0 (25.0) | Not supported | 15.0webkit 22 (unprefixed) |
6.0webkit |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | ? | 26.0 | 1.2 | ? | ? | ? | 33.0 |
See also
Document Tags and Contributors
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Contributors to this page:
fscholz,
chrisdavidmills
Last updated by:
fscholz,