Monday, April 25, 2011

A Lot from a Little: See and Try Generative Music

When you hear complex music, you might imagine a serious-minded composer, choosing each note with a learned and discerning ear. Instead, imagine clicking a few cells on a grid, then clicking “Play.”

It’s called generative music, and it will surprise you. For example, this 17-second video is a musical piece that took all of nine clicks in Otomata, a tool you can try for yourself in a Web page.

Before recording the video, I had lit up nine cells by clicking them. The music came from Otomata’s executing a simple set of rules on the lit cells:

  • Each lit cell has a direction: up, down, left, right.

  • On each beat, all the lit cells move one step in their respective directions.

  • If a cell hits the grid’s edge, the cell bounces back the opposite way. On the bounce, a tone will sound. The pitch (low to high) depends on the position, like a piano key’s pitch depends on its position along the keyboard.

  • If a cell hits another cell, each cell changes direction 90 degrees clockwise.

To avoid overly dissonant results, Otomata uses a limited set of pitches. This enforces a similar feel to Otomata pieces. However, within the general similarity is a world of potential variations.

Having experimented for a while, below is the best Otomata piece I created.

I like the way the piece moves through many different tonal relationships and densities. It was the result of my having clicked eleven cells, plus a few extra clicks to change certain cells’ directions.

Otomata is an implementation of cellular automata, a computational technique that combines simple elements and rules to create complex results—or, I should say, potentially complex results. Depending on your starting state, you can end up with simple cycles or highly complex variations on a theme.

If you try it, a little experimentation should quickly get you interesting results. (For a shortcut, you can start by running or tweaking my second piece.)

While Otomata won’t replace the serious-minded composer, it’s a fun way to see how generative music can make a lot out of a little. Thanks go to Batuhan Bozkurt for creating it and making it freely available.

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