computer music, term used to describe music composed or performed with the aid of a computer. The first substantial piece of music composed on a computer was the Illiac Suite (1956) by the avant-garde composer Lejaren Hiller (1925–94). Computer music can be divided into two distinct production techniques: MIDI (Musical Instrument Digital Interface—see electronic music) and software synthesis. In MIDI production a computer is used to control the outputs of synthesizers and signal-processing devices. Software synthesis, however, involves the use of a computer to mathematically represent and manipulate sounds. This technique was created in the late 1950s by a team headed by Max Mathews at Bell Laboratories in Murray Hill, N.J. The techniques were further advanced by Godfrey Winham and Hubert Howe at Princeton. Today major centers of software synthesis include the Institute for Research and Coordination of Acoustics and Music (IRCAM) in Paris, the Center for Computer Research in Music and Acoustics (CCRMA) at Stanford Univ., the Computer Audio Research Laboratory (CARL) at the Univ. of California at San Diego, and the Media Lab at the Massachusetts Institute of Technology. Software synthesis frequently involves the use of sampling, a technique that represents a sound as a series of discrete measurements of amplitude (loudness). This digital representation of a sound can then be manipulated by various techniques, including filtering, which reduces the loudness of a specific part of the frequency spectrum; time delay, which can be used to simulate various types of echo or reverberation; and frequency shifting, which is used to alter the pitch of a sound.
Sounds can also be directly created by the computer, allowing it to act as a synthesizer. Some recent research into sound production by computers utilizes a technique called physical modeling, which attempts to model the physics of natural instruments or sounds. Computers can also be used to compose music by a process known as algorithmic composition. In this technique various details of a composition are determined by the computer according to a specific program written by the composer. Another area of computer music involves the interaction of humans and machines in live performance. Various techniques have been developed to enable a performer to actively control the output of a computer while a performance is under way.
See C. Roads, Composers and Computers (1985); F. R. Moore, Elements of Computer Music (1990); R. Dobson, A Dictionary of Electronic and Computer Music Technology (1992).