Additive Synthesis And the Harmonic Series

Posted on by Tero Parviainen

Sine waves are simple things and provide a nice entry point to learning audio signal processing. So far we've been able to discuss things like frequency and amplitude using nothing but individual sine wave oscillators.

But the thing is, a solitary sine wave is not very interesting to listen to. It's a blank slate, devoid of any color, character, or drama.

Things start to get much more interesting when we have multiple sine wave oscillators at our disposal. What we can do is combine them to produce more complex sound waves. This technique is called additive synthesis.

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Controlling Frequency and Pitch

Posted on by Tero Parviainen

In the first article we constructed sine wave oscillators that had one particular frequency: 440Hz, or the A4 standard note. In this article we'll see how we can vary the frequency and how this results in different audible pitches.

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JavaScript Systems Music

Learning Web Audio by Recreating The Works of Steve Reich and Brian Eno

Posted on by Tero Parviainen

Systems music is an idea that explores the following question: What if we could, instead of making music, design systems that generate music for us?

This idea has animated artists and composers for a long time and emerges in new forms whenever new technologies are adopted in music-making.

In the 1960s and 70s there was a particularly fruitful period. People like Steve Reich, Terry Riley, Pauline Oliveros, and Brian Eno designed systems that resulted in many landmark works of minimal and ambient music. They worked with the cutting edge technologies of the time: Magnetic tape recorders, loops, and delays.

Today our technological opportunities for making systems music are broader than ever. Thanks to computers and software, they're virtually endless. But to me, there is one platform that's particularly exciting from this perspective: Web Audio. Here we have a technology that combines audio synthesis and processing capabilities with a general purpose programming language: JavaScript. It is a platform that's available everywhere — or at least we're getting there. If we make a musical system for Web Audio, any computer or smartphone in the world can run it.

With Web Audio we can do something Reich, Riley, Oliveros, and Eno could not do all those decades ago: They could only share some of the output of their systems by recording them. We can share the system itself. Thanks to the unique power of the web platform, all we need to do is send a URL.

In this guide we'll explore some of the history of systems music and the possibilities of making musical systems with Web Audio and JavaScript. We'll pay homage to three seminal systems pieces by examining and attempting to recreate them: "It's Gonna Rain" by Steve Reich, "Discreet Music" by Brian Eno, and "Ambient 1: Music for Airports", also by Brian Eno.

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