Terry Riley's "In C"

A Journey Through a Musical Possibility Space

Posted on by Tero Parviainen

In early 2015 I came across a piece of music that was unlike anything I'd ever heard before. It was called "Africa Express Presents: Terry Riley's In C Mali," which didn't ring any bells for me at the time, though it involved a number of musicians I like, including Brian Eno.

When I hit "play," I was surrounded by a cloud of music that seemed to contradict itself at every turn — as if it was in a state of suspended animation, but it kept changing all the time. It was filled with energy and forward motion, yet it was somehow calming. It was highly repetitive but organic. It was rhythmically intricate but it grooved. It was often hard to pin down, but it didn't seem very complicated.

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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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