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Code for the Web Audi "monosynth" from my blog post (http://blog.chrislowis.co.uk/2013/06/05/playing-notes-web-audio-api.html)
$(function () {
var keyboard = qwertyHancock({id: 'keyboard'});
var context = new AudioContext();
/* VCO */
var vco = context.createOscillator();
vco.type = vco.SINE;
vco.frequency.value = this.frequency;
vco.start(0);
/* VCA */
var vca = context.createGain();
vca.gain.value = 0;
/* Connections */
vco.connect(vca);
vca.connect(context.destination);
var isEmpty = function(obj) {
return Object.keys(obj).length === 0;
}
depressed_keys = {}
keyboard.keyDown(function (note, frequency) {
vco.frequency.value = frequency;
vca.gain.value = 1;
depressed_keys[note] = true;
});
keyboard.keyUp(function (note, _) {
delete depressed_keys[note];
if (isEmpty(depressed_keys)) {
vca.gain.value = 0;
}
});
});
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