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additive.html
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<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>Additive Synthesis</title>
<link href="css/audio.css" rel="stylesheet" />
<style>
.slider {
width: 200px;
}
.left-label {
width: 100px;
}
.level-label {
width: 40px;
}
</style>
</head>
<body>
<div>
<span class="title">Additive Synthesis</span>
</div>
<div>
<span class="label left-label">Frequency</span>
<input type="range" id="freq-slider" class="slider" min="20" max="2020" step="10" value="440" />
<br/>
<span class="label left-label">Fundamental</span>
<input type="range" id="level-slider-1" class="slider" h="1" min="0" max="1" step="0.005" value="0.5" />
<span id="level-display-1" class="label level-label"></span>
<span id="freq-display-1" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 2</span>
<input type="range" id="level-slider-2" class="slider" h="2" min="0" max="1" step="0.005" value="0" />
<span id="level-display-2" class="label level-label"></span>
<span id="freq-display-2" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 3</span>
<input type="range" id="level-slider-3" class="slider" h="3" min="0" max="1" step="0.005" value="0" />
<span id="level-display-3" class="label level-label"></span>
<span id="freq-display-3" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 4</span>
<input type="range" id="level-slider-4" class="slider" h="4" min="0" max="1" step="0.005" value="0" />
<span id="level-display-4" class="label level-label"></span>
<span id="freq-display-4" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 5</span>
<input type="range" id="level-slider-5" class="slider" h="5" min="0" max="1" step="0.005" value="0" />
<span id="level-display-5" class="label level-label"></span>
<span id="freq-display-5" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 6</span>
<input type="range" id="level-slider-6" class="slider" h="6" min="0" max="1" step="0.005" value="0" />
<span id="level-display-6" class="label level-label"></span>
<span id="freq-display-6" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 7</span>
<input type="range" id="level-slider-7" class="slider" h="7" min="0" max="1" step="0.005" value="0" />
<span id="level-display-7" class="label level-label"></span>
<span id="freq-display-7" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 8</span>
<input type="range" id="level-slider-8" class="slider" h="8" min="0" max="1" step="0.005" value="0" />
<span id="level-display-8" class="label level-label"></span>
<span id="freq-display-8" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 9</span>
<input type="range" id="level-slider-9" class="slider" h="9" min="0" max="1" step="0.005" value="0" />
<span id="level-display-9" class="label level-label"></span>
<span id="freq-display-9" class="label freq-label"></span>
<br/>
<span class="label left-label">Harmonic 10</span>
<input type="range" id="level-slider-10" class="slider" h="10" min="0" max="1" step="0.005" value="0" />
<span id="level-display-10" class="label level-label"></span>
<span id="freq-display-10" class="label freq-label"></span>
</div>
<div>
<input type="button" id="start" value="start" />
<input type="button" id="stop" value="stop" />
</div>
<div>
<canvas id="visualizer" width="1024" height="300"></canvas>
</div>
<div class="nav">
<a href="subtractive.html">> Subtractive Synthesis</a><br/>
<a href="index.html">> Index</a>
</div>
</body>
<script type="text/javascript" src="js/frequency-visualizer.js"></script>
<script type="text/javascript">
(function () {
var context = new AudioContext();
var visualizer = new App.FrequencyVisualizer(context, document.getElementById('visualizer'));
var oscNode, gainNode, mainGainNode;
var levelSlider = [];
var levelDisplay = [];
var freqDisplay = [];
var harmonicsCount = 10;
var freqSlider = document.getElementById('freq-slider');
freqSlider.addEventListener('input', updateFrequency);
for (var i = 0; i < harmonicsCount; i++) {
levelDisplay[i] = document.getElementById('level-display-' + (i + 1));
freqDisplay[i] = document.getElementById('freq-display-' + (i + 1));
levelSlider[i] = document.getElementById('level-slider-' + (i + 1));
levelSlider[i].addEventListener('input', updateGain);
}
document.getElementById('start').addEventListener('click', start);
document.getElementById('stop').addEventListener('click', stop);
function start() {
if (!oscNode) {
var frequency = parseFloat(freqSlider.value);
oscNode = [];
gainNode = [];
mainGainNode = context.createGain();
mainGainNode.gain.value = 1;
mainGainNode.connect(context.destination);
visualizer.acceptConnection(mainGainNode);
for (var i = 0; i < harmonicsCount; i++) {
oscNode[i] = context.createOscillator();
oscNode[i].frequency.value = frequency * (i + 1);
gainNode[i] = context.createGain();
gainNode[i].gain.value = 0;
oscNode[i].connect(gainNode[i]);
gainNode[i].connect(mainGainNode);
oscNode[i].start();
}
updateGain();
}
}
function stop() {
if (oscNode) {
for (var i = 0; i < harmonicsCount; i++) {
gainNode[i].gain.setValueAtTime(gainNode[i].gain.value, context.currentTime);
gainNode[i].gain.linearRampToValueAtTime(0, context.currentTime + 0.01);
}
setTimeout(function () {
for (var i = 0; i < harmonicsCount; i++) {
oscNode[i].stop();
gainNode[i].disconnect();
}
mainGainNode.disconnect(context.destination)
visualizer.releaseConnection(context.destination);
oscNode = undefined;
gainNode = undefined;
mainGainNode = undefined;
}, 100);
}
}
function updateGain() {
var totalGain = 0;
var maxGain = 0;
for (var i = 0; i < harmonicsCount; i++) {
var gain = parseFloat(levelSlider[i].value);
levelDisplay[i].textContent = gain.toFixed(2);
totalGain += gain;
maxGain = Math.max(gain, maxGain);
}
var gainFactor = totalGain > 0 ? maxGain / totalGain : 0;
if (gainNode) {
for (var i = 0; i < harmonicsCount; i++) {
gainNode[i].gain.setValueAtTime(gainNode[i].gain.value, context.currentTime);
gainNode[i].gain.linearRampToValueAtTime(parseFloat(levelSlider[i].value) * gainFactor, context.currentTime + 0.01);
}
}
}
function updateFrequency() {
for (var i = 0; i < harmonicsCount; i++) {
var frequency = parseFloat(freqSlider.value) * (i + 1);
freqDisplay[i].textContent = frequency + ' hz';
if (oscNode) {
oscNode[i].frequency.value = frequency;
}
}
}
updateFrequency();
updateGain();
})();
</script>
</html>