Web Audio Oscillators - Playing Notes
This keyboard will play notes using a different oscillator for each note. You may notice a clipping sound at the end which is expected.
HTML
<p>
Wave Type:
<select id="waveType">
<option>sine</option>
<option>square</option>
<option>sawtooth</option>
<option>triangle</option>
</select>
Note being played: <input type="text" id="note" size="3">
</p>
<svg xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
width="100%" height="100%" viewBox="-5 -5 1130 450">
<defs>
<rect id="key-white" x="0" y="0" width="20" height="120" rx="3" ry="3" stroke="black" />
<rect id="key-black" x="0" y="0" width="14" height="80" rx="3" ry="3" stroke="black" />
</defs>
<g id="keyboard"s>
<g id="ivory" fill="white">
<use id="C0" xlink:href="#key-white" x="0" />
<use id="D0" xlink:href="#key-white" x="20"/>
<use id="E0" xlink:href="#key-white" x="40"/>
<use id="F0" xlink:href="#key-white" x="60"/>
<use id="G0" xlink:href="#key-white" x="80"/>
<use id="A0" xlink:href="#key-white" x="100"/>
<use id="B0" xlink:href="#key-white" x="120"/>
<use id="C1" xlink:href="#key-white" x="140" />
<use id="D1" xlink:href="#key-white" x="160"/>
<use id="E1" xlink:href="#key-white" x="180"/>
<use id="F1" xlink:href="#key-white" x="200"/>
<use id="G1" xlink:href="#key-white" x="220"/>
<use id="A1" xlink:href="#key-white" x="240"/>
<use id="B1" xlink:href="#key-white" x="260"/>
<use id="C2" xlink:href="#key-white" x="280" />
<use id="D2" xlink:href="#key-white" x="300"/>
<use id="E2" xlink:href="#key-white" x="320"/>
<use id="F2" xlink:href="#key-white" x="340"/>
<use id="G2" xlink:href="#key-white" x="360"/>
<use id="A2" xlink:href="#key-white" x="380"/>
<use id="B2" xlink:href="#key-white" x="400"/>
<use id="C3" xlink:href="#key-white" x="420" />
<use id="D3" xlink:href="#key-white" x="440"/>
<use id="E3" xlink:href="#key-white" x="460"/>
<use id="F3" xlink:href="#key-white" x="480"/>
<use id="G3"...
JavaScript
// Fix up prefixing
window.AudioContext = window.AudioContext || window.webkitAudioContext;
var ctx = new AudioContext(), currentOsc;
function startNote(e) {
var frq = notes[e.currentTarget.id], o = ctx.createOscillator();
$(e.currentTarget).attr("fill","yellow");
o.type = $("#waveType").val();
if (frq) {
$("#note").val(e.currentTarget.id);
o.frequency.value = frq;
o.connect(ctx.destination);
o.start(0);
currentOsc = o;
}
}
function stopNote(e) {
$(e.currentTarget).attr("fill","inherit");
currentOsc.stop(0);
$("#note").val("");
}
$("use").mousedown(startNote);
$("use").mouseup(stopNote);
var notes = {
'C0': 16.35,
'C#0': 17.32,
'Db0': 17.32,
'D0': 18.35,
'D#0': 19.45,
'Eb0': 19.45,
'E0': 20.60,
'F0': 21.83,
'F#0': 23.12,
'Gb0': 23.12,
'G0': 24.50,
'G#0': 25.96,
'Ab0': 25.96,
'A0': 27.50,
'A#0': 29.14,
'Bb0': 29.14,
'B0': 30.87,
'C1': 32.70,
'C#1': 34.65,
'Db1': 34.65,
'D1': 36.71,
'D#1': 38.89,
'Eb1': 38.89,
'E1': 41.20,
'F1': 43.65,
'F#1': 46.25,
'Gb1': 46.25,
'G1': 49.00,
'G#1': 51.91,
'Ab1': 51.91,
'A1': 55.00,
'A#1': 58.27,
'Bb1': 58.27,
'B1': 61.74,
'C2': 65.41,
'C#2': 69.30,
'Db2': 69.30,
'D2': 73.42,
'D#2': 77.78,
'Eb2': 77.78,
'E2': 82.41,
'F2': 87.31,
'F#2': 92.50,
'Gb2': 92.50,
'G2': 98.00,
'G#2': 103.83,
'Ab2': 103.83,
'A2': 110.00,
'A#2': 116.54,
'Bb2': 116.54,
'B2': 123.47,
'C3': 130.81,
'C#3': 138.59,
'Db3': 138.59,
'D3': 146.83,
'D#3': 155.56,
'Eb3': 155.56,
'E3': 164.81,
'F3': 174.61,
'F#3': 185.00,
'Gb3': 185.00,
'G3': 196.00,
'G#3': 207.65,
'Ab3': 207.65,
'A3': 220.00,
'A#3': 233.08,
'Bb3': 233.08,
'B3': 246.94,
'C4': 261.63,
'C#4': 277.18,
'Db4': 277.18,
'D4': 293.66,
'D#4': 311.13,
...