While music made with software feels ubiquitous today, due in part to electronic music and generative AI, it wasn't long ago that the thought of making music on a computer was incredibly impractical. Now, many songs can be produced through entirely digital means, and artificial intelligence programs can even generate complete songs by mimicking styles recognized in their neural webs. Computers in the early days often didn’t even have monitors, and in fact, most institutions had to rent them from the manufacturer because they were so expensive to own.  

One of the first computer science programs started at Purdue University, but WFIU’s home of Indiana University had a unique introduction to computer science – it would be offered by a composer gaining recognition in Europe for his mathematical approach to music composition. Iannis Xenakis came to IU in the fall of 1967, setting up camp in Jacobs’ music addition building, with the mission to install a computer system for making digital music without having to know how to read or write in musical notation.

The device would also simplify his personalized music composition process. Xenakis had been using computers up to this point to create what he calls stochastic music using traditional punch-card computer programming methods. Before computers had screens, you had to configure your code by punching out numbers on cards by hand. You would then feed the series of cards into the computer and wait for the results to get punched onto new cards. 

Xenakis would use mathematical functions to create the form of his songs, with pitch, volume, timbre, and other musical attributes as variables. He would then painstakingly convert the results into musical notation and arrange it for the orchestra. The new computer system he planned to build at IU would save hours of time using a visual-based programming method on an X/Y axis.  

The Polyagogic Information Unit (UPIC) makes it possible to draw your music composition visually. You first begin by drawing waveforms on a small electronic tablet. Traditional synthesizers of the era used analog oscillators to generate tones controlled by a keyboard. Oscillators can be understood as a circuit with an amplifier that enables a feedback loop, creating a certain sustained frequency. Combined with a filter, the frequency can take a variety of shapes - sine waves, square waves, and triangle waves, to name a few. The UPIC would enable a digital version of this phenomenon by creating the potential for customized waveforms that otherwise would not have been available in analog synthesizers.

After choosing a waveform, you could then use a larger electronic tablet – one that looks more like an architect’s easel – to begin drawing the layout of your composition. The X-axis represents time, so your composition would begin on the left and ended on the right, while the Y-axis represents pitch. If you wanted to draw a parabola for example, you would get a sound that is constantly bending its pitch in a direction - a musical tool known as the glissando - that is very characteristic of Xenakis’ style. You could also just scribble all over and get some very interesting, albeit chaotic sounds. In addition, you could apply different algorithms to the composition as a whole, reversing it, inverting it, and so on.

From 1967 to 1972, efforts made to construct this machine at Indiana University were delayed and eventually abandoned for a variety of reasons. But it was mainly due to costs of the necessary digital-to-analog conversion circuits – the main ingredient for converting the computer signals into audible sound. It was no simple task as digital audio was still experimental at the time. Only a few institutions had working audio synthesis and analog conversion, including Bell Labs and Princeton, which utilized the massive PDP-1. 

This computer was more specialized for the task - but at IU they likely only had something like the IBM 1130, a more accessible and economic choice of computing power in 1970. This combined with the fact that these rented computers often didn’t allow a whole lot of customization proved to be a challenge for the ambitious project.

The primary concern with getting analog sound into a computer has to do with the nature of how a computer works. Everything that makes up a computer - every file or instruction - must be represented by a unique string of ones and zeros. To get the computer to understand sounds from the real world, it has to be broken down in the same manner. Pulse Code Modulation (PCM) solves this problem by taking thousands of samples of the sound per second to create a binary representation of the waveform. This task required a lot of customized circuitry that had to be made from scratch. 

While the UPIC would not be completed at Indiana University, it did eventually take shape in 1977 in Issy les Moulineaux, Paris, France and would go on to influence electronic musicians like Aphex Twin and Autechre. You can even download an open-source version of the program for free! But that wasn’t the end of the story for IU’s computer music program - Xenakis’ Center for Automated and Computerized Music at IU would continue and eventually evolve into the Center for Electronic and Computer Music that we know today, comprising two recording studios and state of the art technology in the Music Arts Center, just right next door to where it all started.

In the video below, a realized composition made entirely on the UPIC:

For more about the science of sound, computers, and synthesizers, check out some of our other episodes:

• Your Thoughts Could Be Music: The Encephalophone
• Can tooth fillings pick up radio signals?
• How does Autotune work?
• FM vs AM Radio: Driving through a Tunnel
• The Paper Computer Chip

Sources

Turner, C. (2014) Xenakis in America. Tappan, NY: One Block Avenue.

https://120years.net/upic-system-iannis-xenakis-france-1977/ 

https://en.wikipedia.org/wiki/Electronic_oscillator

Learn more:

Iannis Xenakis was also interested in granular synthesis, or breaking down sound into its smallest parts - first discussed as a topic of quantum physics in 1940. Read about how it works and play with a granular synthesizer in this interactive Introduction to Computer Music textbook from the Center for Electronic and Computer Music website.

An introduction to Early Computing by PBS studios Crash Course

https://www.youtube.com/watch?v=O5nskjZ_GoI