The Biquad Filter is a JavaScript library that implements a cascade of biquad filters
This library implements a biquad filter with the possibility of use a cascade of biquad filters where you can specify the coefficients:
1 + b1*z^-1 + b2*z^-2
One biquad: H1(z) = -----------------------
1 + a1*z^-1 + a2*z^-2
Cascade of biquads: H(z) = g · H1(z) · H2(z) · ... · Hn(z)
where g is the global gain of the cascade of biquads and n is the number of biquad filters.
A working demo for this module can be found here and in the examples folder.
The input format of the coefficients for the library is a JavaScript Array with all the coefficients:
For one biquad filter:
[g, b1, b2, a1, a2]
For two or more biquad filters:
[g, b1_1, b2_1, a1_1, a2_1, b1_2, b2_2, a1_2, a2_2, ... , b1_n, b2_n, a1_n, a2_n ]
where n is the number of biquad filters and g is the global gain of the cascade of biquads.
The binauralFIR object exposes the following API:
| Method | Description |
|---|---|
biquadFilter.setCoefficients(coef) |
Set the coefficients of the filter. |
biquadFilter.process(inputBuffer, outputBuffer) |
Calculate the output of the cascade biquad filter for an inputBuffer. The inputBuffer and the outputBuffer are Arrays with the same length. |
This module is released under the BSD-3-Clause license.
This code has been developed from both Acoustic And Cognitive Spaces and Analysis of Musical Practices IRCAM research teams. It is also part of the WAVE project (http://wave.ircam.fr), funded by ANR (The French National Research Agency), ContInt program, 2012-2015.