biquad
v1.0.1
Published
Tiny utility for creating biquad filter nodes.
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biquad
Tiny utility for creating biquad filter nodes.
Install via npm:
npm install biquad --save
This is designed to be used in a Web Audio API capable browser with browserify. See the excellent browserify handbook for information on how all of that works.
Example
In its simplest form, if you just need one biquad filter, you can use it like so:
var context = new AudioContext();
var biquad = require('biquad');
// Create the biquadFilterNode
var lowpass = biquad.lowpass(context, { frequency: 20000 });
// And then connect it to your audio routing graph
lowpass.connect(context.destination);
If you find yourself creating more than one filter, you can set the
AudioContext
when you require
biquad:
var context = new AudioContext();
var biquad = require('biquad')(context);
// Now we can create multiple filters referring to our context variable
var lowpass = biquad.lowpass({ frequency: 20000 });
var highpass = biquad.highpass({ frequency: 20000 });
API
biquad.filterType([context], options)
Each filterType
is aliased here for convenience. For a full list see
MDN's developer documentation. options
is an object where you can set
the Q
, frequency
and gain
parameters. If we take the example from the
documentation, these are equivalent:
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var biquadFilter = audioCtx.createBiquadFilter();
biquadFilter.type = "lowshelf";
biquadFilter.frequency.value = 1000;
biquadFilter.gain.value = 25;
In biquad:
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var biquad = require('biquad')(audioCtx);
var biquadFilter = biquad.lowshelf({
frequency: 1000,
gain: 25
});
License
MIT © Ben Briggs