Dynamically create a WebAudio buffer (with noise) and play it!

webaudioBufferCreation.js

var AudioContext = AudioContext || webkitAudioContext || mozAudioContext;
var context = new AudioContext();
var node = context.createBufferSource()
  , buffer = context.createBuffer(1, 4096, context.sampleRate)
  , data = buffer.getChannelData(0);

for (var i = 0; i < 4096; i++) {
 data[i] = Math.random();
}
node.buffer = buffer;
node.loop = true;
node.connect(context.destination);
node.start(0);