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StandingWave: Live Musical Audio Synthesis in AS3

December 4, 2007 on 7:16 pm | In Flex, Music, Programming | 8 Comments

I’ve been working on a funky new homebrew software project called StandingWave: a musical audio processing engine built entirely in Flash. My goal in doing this is to explore a world of online interactive music applications in which audio is not merely played back, but generated on the fly — performed, in fact — from an underlying representation of musical events. Such applications might range from a traditional music notation editor to game-like music composition environments to… knows?

Computer music performance is hardly something new, of course. But embedding the capability in Flash, at this point in the world, can make musical applications accessible on the web and amenable to community use in a way that’s never been possible before. Think about what applications like Buzzword and Google Spreadsheets are doing for traditional “productivity apps”.

I’ve started with the audio engine because it’s an interesting technical challenge, although I’m working on some of the other pieces concurrently. I’ve put up an initial crude example that demonstrates sample-based waveform synthesis. This toy application can play back single notes, a chromatic scale and a sample MIDI file at various transpositions, tempos and volumes, and all of this is accomplished by actually synthesizing digital audio signals on the fly, starting from a set of recorded guitar samples and applying gain envelopes, frequency shifting and mixing. Musically, it’s hardly exciting, but it’s a start on the capabilities needed to concretely deliver music in the Flash Player with no external add-ons, and without leaning on the crappy, highly variable MIDI playback delivered by the browser’s native OS.

There’s no waveform audio output API in Flash, so how is this done? Read on…

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8 Comments