1. ELECTRONIC MUSIC............

2. Electronic music is music that employs electronic musical instruments and electronic music technology in its production.[1] In general a distinction can be made between sound produced using electromechanical means and that produced using electronic technology.[2] Examples of electromechanical sound producing devices include the telharmonium, Hammond organ, and the electric guitar. Purely electronic sound production can be achieved using devices such as the Theremin, sound synthesizer, and computer.[3] Electronic music was once associated almost exclusively with Western art music but from the late 1960s on the availability of affordable music technology meant that music produced using electronic means became increasingly common in the popular domain.[4] Today electronic music includes many varieties and ranges from experimental art music to popular forms such as electronic dance music.

3. Late 19th century to early 20th century Telharmonium, Thaddeus Cahill, 1897. The ability to record sounds is often connected to the production of electronic music, but not absolutely necessary for it. The earliest known sound recording device was the phonautograph, patented in 1857 by Édouard-Léon Scott de Martinville. It could record sounds visually, but was not meant to play them back.[5] In 1878, Thomas A. Edison patented the phonograph, which used cylinders similar to Scott's device. Although cylinders continued in use for some time, Emile Berliner developed the disc phonograph in 1887.[6] A significant invention, which was later to have a profound effect on electronic music, was Lee DeForest's triode audion. This was the first thermionic valve, or vacuum tube, invented in 1906, which led to the generation and amplification of electrical signals, radio broadcasting, and electronic computation, amongst other things.

4. Before electronic music, there was a growing desire for composers to use emerging technologies for musical purposes. Several instruments were created that employed electromechanical designs and they paved the way for the later emergence of electronic instruments. An electromechanical instrument called the Telharmonium (sometimes Teleharmonium or Dynamophone) was developed by Thaddeus Cahill in the years 1898-1912. However, simple inconvenience hindered the adoption of the Telharmonium, due to its immense size. The first electronic instrument is often viewed to be the Theremin, invented by Professor Léon Theremin circa 1919–1920.[7] Another early electronic instrument was the Ondes Martenot, which was most famously used in the Turangalîla-Symphonie by Olivier Messiaen as well as other works by him. It was also used by other, primarily French, composers such as Andre Jolivet.

5. CHANCE MUSIC {JOHN CAGE}...... http://www.biographybase.com/biography/C age_John.html

6. "Open form" chance music Open form is a term sometimes used for mobile or polyvalent musical forms, where the order of movements or sections is indeterminate or left up to the performer. Roman Haubenstock-Ramati composed a series of influential "mobiles" such as Interpolation (1958). However, "open form" in music is also used in the sense defined by the art historian Heinrich Wölfflin (Renaissance und Barock, 1888) to mean a work which is fundamentally incomplete, represents an unfinished activity, or points outside of itself. In this sense, a "mobile form" can be either "open" or "closed". An example of a closed mobile musical composition is Stockhausen's Zyklus (1959). Terry Riley's In C (1964) was composed of 53 short sequences; each member of the ensemble can repeat a given sequence as many times as desired before going on to the next, making the details of each performance of In C unique though, because the overall course is fixed, it is a closed form.

7. Aleatoric music (also aleatory music or chance music; from the Latin word alea, meaning "dice") is music in which some element of the composition is left to chance, and/or some primary element of a composed work's realization is left to the determination of its performer(s). The term is most often associated with procedures in which the chance element involves a relatively limited number of possibilities. The term became known to European composers through lectures by acoustician Werner Meyer-Eppler at Darmstadt International Summer Courses for New Music in the beginning of the 1950s. According to his definition, "a process is said to be aleatoric... if its course is determined in general but depends on chance in detail" (Meyer-Eppler 1957, 55).

8. REFERENCES: http://www.googlehttp://www.google.com http://www.wikipedia.com