TutsPlus - Fun With Web Audio

You may have used the audio tag to play sound in the past. While that works fine for simply playing a sound, it doesn't give us much control over the quality or timing of the playback. Enter the Web Audio API, a powerful new way of playing and manipulating sound in the browser with JavaScript.
In this course, Tuts+ instructor Stuart Memo will show you how to build something you don't usually see in a web browser: a synthesizer. Stuart will demonstrate how to build a little musical keyboard with real-time additive audio synthesis. You'll also get a chance to experiment with analyzing sound and visualizing audio information on-screen.