Granular synthesis
Sound synthesis method involving samples shorter than 0.1 seconds
Granular synthesis is a sound synthesis method that operates on the microsound time scale.
It is based on the same principle as sampling. However, the samples are split into small pieces of around 1 to 100 ms in duration, called grains. Multiple grains may be layered on top of each other, and may play at different speeds, phases, volume, and frequency, among other parameters.
At low speeds of playback, the result is a kind of soundscape, often described as a cloud, that is manipulated in a manner unlike that of natural sound sampling or other synthesis techniques. At high speeds, the result is heard as a note or notes of a novel timbre. By varying the waveform, envelope, duration, spatial position, and density of the grains, many different sounds can be produced.
Both have been used for musical purposes: as sound effects, raw material for further processing by other synthesis or digital signal processing effects, or as complete musical works in their own right. Conventional effects that can be achieved include amplitude modulation and time stretching. More experimentally, stereo or multichannel scattering, random reordering, disintegration and morphing are possible.
01History
In 1947, Dennis Gabor introduced the idea that sounds can be represented by a series of elementary "grains," each grain being a short pulse containing both temporal and frequency information. Greek-French composer Iannis Xenakis is known as the inventor of granular synthesis, having expanded upon Gabor's theoretical foundation.
The composer Iannis Xenakis (1960) was the first to explicate a compositional theory for grains of sound. He began by adopting the following lemma: "All sound, even continuous musical variation, is conceived as an assemblage of a large number of elementary sounds adequately disposed in time. In the attack, body, and decline of a complex sound, thousands of pure sounds appear in a more or less short interval of time
." Xenakis created granular sounds using analog tone generators and tape splicing. These appear in the composition Analogique A-B for string orchestra and tape (1959).
American composer Curtis Roads was the first to implement granular synthesis on a computer in 1974. In 1986, Canadian composer Barry Truax implemented real-time granular synthesis using the DMX-1000 Signal Processing Computer.
02Microsound
This includes all sounds on the time scale shorter than musical notes, the sound object time scale, and longer than the sample time scale. Specifically, this is shorter than one tenth of a second and longer than 10 milliseconds, which includes part of the audio frequency range (20 Hz to 20 kHz) as well as part of the infrasonic frequency range (below 20 Hz, rhythm).
These sounds include transient audio phenomena and are known in acoustics and signal processing by various names including sound particles, quantum acoustics, sonal atom, grain, glisson, grainlet, trainlet, microarc, wavelet, chirplet, fof, time-frequency atom, pulsar, impulse, toneburst, tone pip, acoustic pixel, and others. In the frequency domain they may be named kernel, logon, and frame, among others.
Micromontage is musical montage with microsound.
Microtime is the level of "sonic" or aural "syntax" or the "time-varying distribution of...spectral energy".
05Discography
- Curtis Roads (2004). CD with Microsounds. MIT Press. ISBN 0-262-18215-7. Contains excerpts of nscor and Field (1981). Microsounds at Discogs.
- nscor (1980), New Computer Music (1987) Wergo 2010-50 at Discogs (list of releases)
- Iannis Xenakis. Analogique A-B (1959), on Alpha & Omega at Discogs and Music For Strings at Discogs
- Truax, Barry (1987). Digital Soundscapes Digital Soundscapes at Discogs
Sources and credits
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