Extract from SitePoint article “Dynamic Sound with the Web Audio API” by Robby Ingebretsen
Published June 24, 2015
This article is part of a web dev series from Microsoft. Thank you for supporting the partners who make SitePoint possible.
Before the Web Audio API, HTML5 gave us the audio element. It might seem hard to remember now, but prior to the audio element, our best option for sound in a browser was a plugin! The audio element was, indeed, exciting but it had a pretty singular focus. It was essentially a video player without the video, good for long audio like music or a podcast, but ill-suited for the demands of gaming. We put up with (or found workarounds for) looping issues, concurrent sound limits, glitches and total lack of access to the sound data itself.
Fortunately, our patience has paid off. Where the audio element may have been lacking, the Web Audio API delivers. It gives us unprecedented control over sound and it’s perfect for everything from gaming to sophisticated sound editing. All this with a tidy API that’s really fun to use and well supported.
Let’s be a little more specific: Web Audio gives you access to the raw waveform data of a sound and lets you manipulate, analyze, distort or otherwise modify it. It is to audio what the canvas API is to pixels. You have deep and mostly unfettered access to the sound data. It’s really powerful!
This tutorial is the second in a series on Flight Arcade – built to demonstrate what’s possible on the web platform and in the new Microsoft Edge browser and EdgeHTML rendering engine. Interactive code and examples for this article are also located at: http://www.flightarcade.com/learn/
Even the earliest versions of Flight Simulator made efforts to recreate the feeling of flight using sound. One of the most important sounds is the dynamic pitch of the engine which changes pitch with the throttle. We knew that, as we reimagined the game for the web, a static engine noise would really seem flat, so the dynamic pitch of the engine noise was an obvious candidate for Web Audio.