Web/API/BiquadFilterNode/BiquadFilterNode

The BiquadFilterNode() constructor of the Web Audio API creates a new BiquadFilterNode object, which represents a simple low-order filter, and is created using the AudioContext.createBiquadFilter() method.

Syntax

var biquadFilterNode = new BiquadFilterNode(context, options)

Parameters

Inherits parameters from the AudioNodeOptions dictionary.

context

A reference to an AudioContext.

options Optional

Options are as follows:

type: One of "lowpass", "highpass", "bandpass", "lowshelf", "highshelf", "peaking", "notch", "allpass". The meaning of the other options depends on the value of this one. The defaults for all are as follows:
- Q: 1
- detune: 0
- frequency: 350
- gain: 0

lowpass: (Default) Allows frequencies below a cutoff frequency to pass through, and attenuates frequencies above the cutoff. This is a standard second-order resonant lowpass filter with 12dB/octave rolloff.

Q: Controls how peaked the response will be at the cutoff frequency. A large value makes the response more peaked. Please note that for this filter type, this value is not a traditional Q, but is a resonance value in decibels.
frequency: The cutoff frequency.
gain: Not used.

highpass: A highpass filter is the opposite of a lowpass filter. Frequencies above the cutoff frequency are passed through, but frequencies below the cutoff are attenuated. It implements a standard second-order resonant highpass filter with 12dB/octave rolloff.

Q: Controls how peaked the response will be at the cutoff frequency. A large value makes the response more peaked. Please note that for this filter type, this value is not a traditional Q, but is a resonance value in decibels.
frequency: The cutoff frequency.
gain: Not used.

bandpass: A bandpass filter allows a range of frequencies to pass through and attenuates the frequencies below and above this frequency range. It implements a second-order bandpass filter.

Q: Controls the width of the band. The width becomes narrower as the Q value increases.
frequency: The center of the frequency band.
gain: Not used.

lowshelf: The lowshelf filter allows all frequencies through, but adds a boost (or attenuation) to the lower frequencies. It implements a second-order lowshelf filter.

Q: Not used.
frequency: The upper limit of the frequences where the boost, or attenuation, is applied.
gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

highshelf: The highshelf filter is the opposite of the lowshelf filter and allows all frequencies through, but adds a boost to the higher frequencies. It implements a second-order highshelf filter.

Q: Not used.
frequency: The lower limit of the frequences where the boost, or attenuation, is applied.
gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

peaking: The peaking filter allows all frequencies through, adding a boost, or attenuation, to a range of frequencies.

Q: The width of the band of frequencies that are boosted. A large value implies a narrow width.
frequency: The center frequency of the boost range.
gain: The boost, in dB, to be applied. If the value is negative, the frequencies are attenuated.

notch: The notch filter (also known as a band-stop, or band-rejection filter) is the opposite of a bandpass filter. It allows all frequencies through, except for a set of frequencies.

Q: The width of the band of frequencies that are attenuated. A large value implies a narrow width.
frequency: The center frequency of the attenuation range.
gain: Not used.

allpass: An allpass filter allows all frequencies through, but changes the phase relationship between the various frequencies. It implements a second-order allpass filter.

Q: The sharpness of the phase transition at the center frequency. A larger value implies a sharper transition and a larger group delay.
frequency: The frequency where the center of the phase transition occurs. Viewed another way, this is the frequency with maximal group delay.
gain: Not used.

Return value

A new BiquadFilterNode object instance.

Specifications

Specification	Status	Comment
Web Audio APIThe definition of 'BiquadFilterNode()' in that specification.	Working Draft	Initial definition.

Browser Compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`BiquadFilterNode()` constructor	Chrome Full support 55 Notes' Full support 55 Notes' Notes' Before Chrome 59, the default values were not supported.	Edge Full support 79	Firefox Full support 53	IE No support No	Opera Full support 42 Notes' Full support 42 Notes' Notes' Before Opera 46, the default values were not supported.	Safari No support No	WebView Android Full support 55 Notes' Full support 55 Notes' Notes' Before version 59, the default values were not supported.	Chrome Android Full support 55 Notes' Full support 55 Notes' Notes' Before Chrome 59, the default values were not supported.	Firefox Android Full support 53	Opera Android Full support 42 Notes' Full support 42 Notes' Notes' Before Opera 46, the default values were not supported.	Safari iOS No support No	Samsung Internet Android Full support 6.0 Notes' Full support 6.0 Notes' Notes' Before Samsung Internet 7.0, the default values were not supported.

Legend

Full support: Full support
No support: No support
See implementation notes.': See implementation notes.

BiquadFilterNode() by Mozilla Contributors is licensed under CC-BY-SA 2.5.