https://github.com/ben-eb/biquad

Tiny utility for creating biquad filter nodes.
https://github.com/ben-eb/biquad

Last synced: 7 days ago
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Tiny utility for creating biquad filter nodes.

• Host: GitHub
• URL: https://github.com/ben-eb/biquad
• Owner: ben-eb
• License: mit
• Created: 2015-05-01T17:54:34.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-05-07T13:03:59.000Z (over 9 years ago)
• Last Synced: 2024-10-18T08:31:27.143Z (28 days ago)
• Language: JavaScript
• Size: 121 KB
• Stars: 2
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-MIT

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README

        
# biquad [![NPM version](https://badge.fury.io/js/biquad.svg)](http://badge.fury.io/js/biquad) [![Dependency Status](https://gemnasium.com/ben-eb/biquad.svg)](https://gemnasium.com/ben-eb/biquad)

> Tiny utility for creating biquad filter nodes.

Install via [npm](https://npmjs.org/package/biquad):

```

npm install biquad --save

```

This is designed to be used in a Web Audio API capable browser with

[browserify](https://github.com/substack/browserify). See the excellent

[browserify handbook](https://github.com/substack/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:

```js

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:

```js

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][docs]. `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:

```js

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

var biquadFilter = audioCtx.createBiquadFilter();

biquadFilter.type = "lowshelf";

biquadFilter.frequency.value = 1000;

biquadFilter.gain.value = 25;

```

In biquad:

```js

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

var biquad = require('biquad')(audioCtx);

var biquadFilter = biquad.lowshelf({

    frequency: 1000,

    gain: 25

});

```

## License

MIT © [Ben Briggs](http://beneb.info)

[docs]: https://developer.mozilla.org/en-US/docs/Web/API/BiquadFilterNode.type