Electroacoustic music is a genre of popular and Western art music in which composers use technology to manipulate the timbres of acoustic sounds, sometimes by using audio signal processing, such as reverb or harmonizing, on acoustical instruments. It originated around the middle of the 20th century, following the incorporation of electric sound production into compositional practice. The initial developments in electroacoustic music composition to fixed media during the 20th century are associated with the activities of the Groupe de recherches musicales at the ORTF in Paris, the home of musique concrète, the Studio for Electronic Music in Cologne, where the focus was on the composition of elektronische Musik, and the Columbia-Princeton Electronic Music Center in New York City, where tape music, electronic music, and computer music were all explored. Practical electronic music instruments began to appear in the early 20th century.
Musique concrète
Tape music is an integral part of musique concrète, which uses the tape recorder as its central musical source. The music can utilise pre-recorded sound fragments and the creation of loops, which can be altered and manipulated through techniques such as editing and playback speed manipulation. The work of Halim El-Dabh is perhaps the earliest example of tape (or, in this case, Wire recording) music. El-Dabh's The Expression of Zaar, first presented in Cairo, Egypt, in 1944, was an early work using musique concrète–like techniques similar to those developed in Paris during the same period. El-Dabh would later become more famous for his work at the Columbia-Princeton Electronic Music Center, where in 1959 he composed the influential piece Leiyla and the Poet.
Composer John Cage's assembly of the Williams Mix serves as an example of the rigors of tape music. First, Cage created a 192-page score. Over the course of a year, 600 sounds were assembled and recorded. Cut tape segments for each occurrence of each sound were accumulated on the score.