UPIC

Xenakis was an architect before he was a composer, and he thought in graphs. At his research centre CEMAMu outside Paris he built a system around a large drawing tablet and an electromagnetic pen. Horizontal was time, vertical was pitch, and every line drawn became a voice. Waveforms and envelopes were drawn the same way and assigned to the lines. The first piece made with it, Mycènes Alpha, appeared in 1978.

Early versions computed for a long while before anything could be heard. Only in the late 1980s, on a PC with dedicated sound hardware, could you draw and listen at the same time. UPIC was used in education as much as by composers — children grasp that a rising line sounds brighter long before they can read notation. The free program IanniX, from the 2000s, carries the same idea forward.