The computer as a musical tool

The direct synthesis of sound by computer was first described in 1961 by Max Mathews and coworkers at the Bell Telephone Laboratories, Murray Hill, N.J., U.S. Computer sound synthesis involves the description of a sound waveform as a sequence of numbers representing the instantaneous amplitudes of the wave over very small successive intervals of time. The waveform itself is then generated by the process of digital-to-analog conversion, in which first the numbers are converted to voltage steps in sequence and then the steps are smoothed to produce the final waveform.

Unlike the electronic music synthesizers of the 1960s and '70s, in which electronic circuits performed specific waveform generation and processing functions, computer-based music composition systems are capable of performing any function that can be described as a computational procedure, or algorithm. The algorithm is written by a composer or programmer as a series of instructions that are stored in digital media (i.e., punched cards, magnetic tape, or magnetic disks) and "loaded" into the computer when the music is to be realized. The composer then also writes a score that specifies properties of the individual sound events that make up the composition.

A great variety of sound-synthesis and music-composition algorithms have been developed at research institutions around the world. Music V, created in 1967-68, is the most widely used sound-synthesis program to have been developed at Bell Laboratories. Music V consists of computer models of oscillator and amplifier modules, plus procedures for establishing interactions among the modules. Another widely used synthesis algorithm is Frequency Modulation (FM) Synthesis. Described by John Chowning of Stanford University (Palo Alto, Calif., U.S.) in 1973, FM produces a wide variety of complex timbres by rapidly varying the frequency of one waveform in proportion to the amplitude of another waveform.

As computer technology developed and computers became more powerful and less expensive during the 1970s and '80s, the flexibility and sound-production capability of computer-based music systems attracted an increasing proportion of experimental music composers. By the end of the 1980s, computer music systems surpassed tape studio techniques and analog synthesizers as the electronic composition medium of choice among modern and experimental music composers.