danigb/dcbias

A DCBias node for introducing a fixed-value signal in your audio graph

openmusic-dcbias

A node for introducing a fixed-value signal in your audio graph

You can use it for things such as:

• shifting the signal upwards/downwards when connected to a gain node (the demo)
• modifying the value of an AudioParam by a fixed-value. E.g. adding -100. by setting the gain.value to -100.

Using it

Create an audio context.

var audioContext = new AudioContext();

Require the code somehow:

var DCBias = require('openmusic-dcbias');

or

<script src="DCBias.js"></script>

Then create instances by passing the context to the function:

var bias = DCBias(audioContext);

And it's ready to be used!

// Raise the frequency by 100
var oscillator = audioContext.createOscillator();
bias.gain.value = 100;
bias.connect(oscillator.frequency);

// Saturate/clip a "mixer"
var mixer = audioContext.createGain();
oscillator.connect(mixer);
bias.gain.value = 1;
bias.connect(mixer);
// the output of mixer is now half of the usual oscillator output as we've shifted it upwards by 1

Demo

Run npm install first to have all the dependencies (i.e. the oscilloscope component) installed.

Then open index.html. Code is in demo.js.

** YOU NEED SUPPORT FOR WEB COMPONENTS IN YOUR BROWSER BECAUSE WE'RE NOT SHIMMING ANYTHING IN **

Firefox: go to about:config, find dom.webcomponents.enabled and set it to true.

Chrome: maybe nothing to do?