BiquadFilterNode.gain - Web APIs 编辑

The gain property of the BiquadFilterNode interface Is a a-rate AudioParam, a double representing the gain used in the current filtering algorithm.

When it takes a positive value it is a real gain, when negative it is an attenuation.

It is expressed in dB, has a default value of 0 and can take a value in a nominal range of -40 to 40.

Syntax

var audioCtx = new AudioContext();
var biquadFilter = audioCtx.createBiquadFilter();
biquadfilter.gain.value = 25;

Note: Though the AudioParam returned is read-only, the value it represents is not.

Value

An AudioParam.

Example

The following example shows basic usage of an AudioContext to create a Biquad filter node. For a complete working example, check out our voice-change-o-matic demo (look at the source code too).

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

//set up the different audio nodes we will use for the app
var analyser = audioCtx.createAnalyser();
var distortion = audioCtx.createWaveShaper();
var gainNode = audioCtx.createGain();
var biquadFilter = audioCtx.createBiquadFilter();
var convolver = audioCtx.createConvolver();

// connect the nodes together

source = audioCtx.createMediaStreamSource(stream);
source.connect(analyser);
analyser.connect(distortion);
distortion.connect(biquadFilter);
biquadFilter.connect(convolver);
convolver.connect(gainNode);
gainNode.connect(audioCtx.destination);

// Manipulate the Biquad filter

biquadFilter.type = "lowshelf";
biquadFilter.frequency.value = 1000;
biquadFilter.gain.value = 25;

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using the Web Audio API