My Blog: projects, sketches, works in progress, thoughts, and inspiration.

Tagged: software

For a while I’ve been interested in exploring sound as a new medium. Pure Data is a sound program which I’ve been particularly interested in. The program is something like a visual programming language, with a similar interface to quartz composer. Objects which represent chunks of code are placed on the canvas. These objects have inputs and outputs through which they send and receive data in the form of numbers, strings, and audio signals. Some graphic interface elements call also be added to control applications.

Starting to work with Pure Data is a little intimidating. Objects added to the stage are blank and you have to type into them what object the should be. Until you understand what the basic objects are and how they interact trying to get anything working isn’t easy. For at least a good while I’ve been opening up Pure Data every few months only to put it away again after beating my head against it for a while.

For my recent flash game, Pulsus, I decided to create the sound using Pure Data to force myself to learn the program. I managed to cobble together a basic understanding and build a few synthesizers and sound generators.


I used this first patch to create most of the sound effects in the game. For a number of oscillators the pitch and envelope can be changed. The pitches can create harmonics, harmonies, or dissonant chords. The envelope, the volume over the course of the sound, creates pulsing tones, short beats, and any other type of tone. I also added an amplitude modulator and a global envelope to add some more control.


In my next experiment I created a simple mono synthesizer. Key inputs, from my computer keyboard, are mapped into midi notes. When a key is pressed the frequency slides to that note if another note is still playing. Key presses trigger the envelope generator which reads data from an array (top right). The synth also has frequency and amplitude modulators and reads the waveform from a table to include harmonics.


Next I build a polyphonic synthesizer which has a separate oscillator for every note in the scale.

Here are the pure data files for these patches in case they might be useful to anyone, but again they are not super efficient, organized, or annotated.

These are my first moderately successful explorations with Pure Data. Some things, I realize, are not done as efficiently as possible, but I’m working things out in the next iteration. My next frustration is to find a way to control the instruments I build. I need a midi sequencer with which I can construct songs that could then send the midi info to Pure Data. I tried using a garage band plugin to output midi info from garage band but It came out pretty garbled in PD, I could be doing something wrong though. Any thoughts on how I should go about this?

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context free art spirals

If you are interested in geometric fractals, Context Free Art is a very interesting program it play with. The interface consists of a code area on the right, and a rendering area on the left. The very simple script only contains a few commands, but through recursion can create fantastic fractals.

The script allows you to draw squares, triangles, and circles, and to transform them in a few different ways and color them. You can create custom rules which transform whichever rule they contain. By creating recursive functions like this just about any geometric fractal can be created. Although the program is very limited, I find it very interesting how much can be created only with transformations of three basic shapes. The program also has the ability to export both raster (pixel based) and vector images, which makes it a useful tool for creating shapes and textures, and renders the script live. If you would like to go further with fractal generation, I recommend Processing, but Context Free Art is so simple to learn it’s a fun tool to play around with.

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Processing is an open source programming language and environment developed for artists and designers to quickly and easily develop programs for any application. The language is java based, fairly easy to learn, even for the non-programmer, which includes many functions to create dynamic graphics. The environment allows for easy debugging of scripts, testing, and finally exporting of your programs to web applets or to an application for any operating system. And best of all Processing is completely free to download and very well documented, with definitions and examples for every function.

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