BiquadFilterNode

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构造函数
特性
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范例
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BiquadFilterNode 接口表示简单低阶过滤器，且创建是使用 AudioContext.createBiquadFilter() 方法。它是 AudioNode 可以表示不同种类的过滤器、色调控制设备及图形均衡器。 A BiquadFilterNode 总是准确拥有一个输入和一个输出。

输入数	`1`
输出数	`1`
通道计数模式	`"max"`
通道计数	`2` (不用于默认计数模式)
通道解释	`"speakers"`

构造函数

BiquadFilterNode(): 创建新的实例化 BiquadFilterNode 对象。

特性

继承的特性来自其父级， AudioNode .

注意 : Though the AudioParam objects returned are read-only, the values they represent are not.

BiquadFilterNode.frequency 只读

是 a-rate


									AudioParam

, a double representing a frequency in the current filtering algorithm measured in hertz (Hz).

BiquadFilterNode.detune 只读

是 a-rate


									AudioParam

representing detuning of the frequency in cents .

BiquadFilterNode.Q 只读

是 a-rate


									AudioParam

, a double representing a Q factor ，或 quality factor .

BiquadFilterNode.gain 只读

是 a-rate


									AudioParam

, a double representing the gain used in the current filtering algorithm.

BiquadFilterNode.type

Is a string value defining the kind of filtering algorithm the node is implementing.

The meaning of the different parameters depending of the type of the filter (detune has the same meaning regardless, so isn't listed below)
`type`	描述	`frequency`	`Q`	`gain`
`lowpass`	Standard second-order resonant lowpass filter with 12dB/octave rolloff. Frequencies below the cutoff pass through; frequencies above it are attenuated.	The cutoff frequency.	Indicates how peaked the frequency is around the cutoff. The greater the value is, the greater is the peak.	Not used
`highpass`	Standard second-order resonant highpass filter with 12dB/octave rolloff. Frequencies below the cutoff are attenuated; frequencies above it pass through.	The cutoff frequency.	Indicates how peaked the frequency is around the cutoff. The greater the value, the greater the peak.	Not used
`bandpass`	Standard second-order bandpass filter. Frequencies outside the given range of frequencies are attenuated; the frequencies inside it pass through.	The center of the range of frequencies.	Controls the width of the frequency band. The greater the `Q` value, the smaller the frequency band.	Not used
`lowshelf`	Standard second-order lowshelf filter. Frequencies lower than the frequency get a boost, or an attenuation; frequencies over it are unchanged.	The upper limit of the frequencies getting a boost or an attenuation.	Not used	The boost, in dB, to be applied; if negative, it will be an attenuation.
`highshelf`	Standard second-order highshelf filter. Frequencies higher than the frequency get a boost or an attenuation; frequencies lower than it are unchanged.	The lower limit of the frequencies getting a boost or an attenuation.	Not used	The boost, in dB, to be applied; if negative, it will be an attenuation.
`peaking`	Frequencies inside the range get a boost or an attenuation; frequencies outside it are unchanged.	The middle of the frequency range getting a boost or an attenuation.	Controls the width of the frequency band. The greater the `Q` value, the smaller the frequency band.	The boost, in dB, to be applied; if negative, it will be an attenuation.
`notch`	标准 notch filter, also called a band-stop or band-rejection filter. It is the opposite of a bandpass filter: frequencies outside the give range of frequencies pass through; frequencies inside it are attenuated.	The center of the range of frequencies.	Controls the width of the frequency band. The greater the `Q` value, the smaller the frequency band.	Not used
`allpass`	Standard second-order allpass filter. It lets all frequencies through, but changes the phase-relationship between the various frequencies.	The frequency with the maximal group delay , that is, the frequency where the center of the phase transition occurs.	Controls how sharp the transition is at the medium frequency. The larger this parameter is, the sharper and larger the transition will be.	Not used

方法

继承方法来自其父级 AudioNode .

BiquadFilterNode.getFrequencyResponse()

范例

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 源代码 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.setValueAtTime(1000, audioCtx.currentTime);
biquadFilter.gain.setValueAtTime(25, audioCtx.currentTime);

规范

规范	状态	注释
Web 音频 API The definition of 'BiquadFilterNode' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`BiquadFilterNode`	Chrome 14	Edge ≤18	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`BiquadFilterNode()` 构造函数	Chrome 55	Edge ≤79	Firefox 53	IE 不支持 No	Opera 42	Safari ?	WebView Android 55	Chrome Android 55	Firefox Android 53	Opera Android 42	Safari iOS ?	Samsung Internet Android 6.0
`Q`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`detune`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`frequency`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`gain`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`getFrequencyResponse`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0
`type`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0

图例

完整支持
不支持
兼容性未知 ?

另请参阅

使用 Web 音频 API

元数据

最后修改： 2020 年 1 月 22 日

Web 音频 API
BiquadFilterNode
构造函数
1. BiquadFilterNode()
特性
1. detune
2. frequency
3. gain
4. Q
5. type
方法
1. getFrequencyResponse()
继承：
1. AudioNode
2. EventTarget
Related pages for Web Audio API

在此页

构造函数

特性

方法

范例

规范

浏览器兼容性

图例

另请参阅

相关话题