Computer Sound Synthesis in 1951: The Music of CSIRAC

The Australian-built "automatic computer" initially known as the CSIR Mk1, and later known as CSIRAC, was one of the world's earliest stored-program electronic digital computers (Williams 1997). (See Figure 1.) Coincidentally, it may also have been the first computer to play music, even though later work done elsewhere in the 1950s is clearly the origin of computer music as we know the field today.

Developed in Sydney in the late 1940s by the Council for Scientific and Industrial Research (CSIR), the CSIR Mk1 ran its first program in November 1949. Geoff Hill, a mathematician and Australia's first real software engineer, programmed the CSIR Mk1 to play popular musical melodies through its loudspeaker starting in 1951, if not 1950. The CSIR Mk1 was moved to the University of Melbourne in June 1955 and renamed CSIRAC (McCann and Thorne 2000). It performed useful and trailblazing service there until 1964. During CSIRAC's time in Melbourne, the mathematics professor Thomas Cherry programmed it to perform music, developing a system and program such that anyone who understood standard musical notation could create a punched-paper data tape for CSIRAC to perform that music.

Although the music performed by the CSIR Mk1 may seem crude and unremarkable compared to the most advanced musical developments of the time, and especially to what is possible now, it is probably the first music in the world to be performed on a computer, and the means of production lay at the leading edge of technological sophistication at that time. These first steps of using a computer in a musical sense occurred in isolation, but they are still interesting, because the leap of imagination in using the flexibility of a general-purpose computer to create music and the programming ingenuity required to achieve it are significant. CSIRAC took some initial steps in that direction.

An Overview of CSIRAC

In the 1940s, modern physics had advanced to such a stage that the calculations required were enormous, manifold, and tedious. To address this problem, calculating machines had been developed, such as the "linear equations machine," the "differential analyzer," and the "multi-register accounting machine." However, these calculating machines still required much human intervention, so there was a desire to build an automatic calculator with some sort of memory to store the data and also the instructions of what to do with the data. Two major technological advances of the time allowed the realization of an automatic calculator with memory. One was the thermionic valve (the vacuum tube), which was used as a switching device or as an electronic relay. The other was mercury delay-line "memory," which had been used in radar systems during World War II. This memory system could be adapted for use in an automatic calculator.

The CSIR Radiophysics division was active during World War II, developing portable radar systems for Australian servicemen for jungle warfare. In 1941, Maston Beard joined the Radiophysics Laboratory, where, with Trevor Pearcey, he was instrumental in the development of Australia's first computer. This work was undertaken by the Radiophysics Laboratory as they were the leading experts in pulse technology and valve electronics (McCann and Thorne 2000).

Trevor Pearcey and Maston Beard officially began the "Electronic Computer" project in 1947. (Although the terms "electronic computer" and "automatic computer" may seem tautological today, in the 1940s to 1950s, the term "computer" typically denoted a secretary who operated a calculating machine.) In addition, in the same year the University of Pennsylvania published previously secret details of the computer known as ENIAC. In mid 1948, Pearcey completed and published the fundamental logical design of the computer in two papers. The overriding considerations of the logical design were engineering and programming simplicity, as this was intended to be a comprehensive prototype for a larger and more capable machine. The construction began in 1948. The first program, which simply multiplied two numbers, was run late in 1949, probably in November, but nobody recorded the exact date. Trevor Pearcey recalls, "We all shouted 'Hooray!' and went back to work" (Pearcey 1996).

Figure 1.

CSIRAC...