The
technique of granular synthesis is becoming more common as a tool in computer
composition, yet it could be seen as more than just a basic tool. The development
in granular synthesis has now reached a point at which it is possible,
and relatively common, to create entire compositions using only this technique.
Granular synthesis involves generating thousands of tiny sonic events
known as grains. These grains can be considered the building blocks of
sound, or atomic sound particles. They can be combined to generate new
sounds, timbres, or sonic textures. Granular synthesis is unique because
it collapses the time and frequency domains within the concept of the grain.
This collapse in domain allows the limits of sonic perception to be exploited.
The textures that can
be created using granular synthesis are very exciting as they allow for
a soundscape that is totally controllable by the composer. Not only is
the composer in control of each timbre, each duration, and each pitch within
the piece, but also how these parts interact with each other. This advantage
of complete controllability of all aspects of the texture is carried out
at the macro, as well as the micro level. Unfortunately such a large amount
of control makes it difficult to keep control of all the levels. This is
overcome by using statistical forms of control.
Computer synthesis has
been common for a long time now. There are many forms of computer synthesis
including additive synthesis, subtractive synthesis, distortion synthesis,
frequency modulation, amplitude modulation, formant (FOF) synthesis, dynamic
stochastic synthesis, graphic synthesis, interpolation synthesis, table-lookup
synthesis, time-varying wave form synthesis, waveshaping synthesis, and
window function synthesis (Roads 1996a). Granular synthesis could be seen
as a form of additive synthesis but its approach and sonic results are
quite different from additive synthesis.
Until very recently
the techniques and means associated with granular synthesis were not available
to many people. This was due to the nature of granular synthesis, in that
it can contain literally thousands of parameterized events just to specify
one second of sound. Processing such large amounts of data required the
work of mainframe computers equipped with a digital to analog converter
(DAC). For many years Bell Telephone Laboratory in the USA was the only
place capable of any type of sound synthesis (Roads 1996a: 87). Later there
were facilities available at IRCAM in France (Risset 1985:11), University
of California (Roads 1996a: 169), and Massachusetts Institute of Technology
(Roads 1996a: 547).
Even with such large
computers the processing could take a week just to get basic results. Until
about 1990 the most prominent people involved with granular synthesis were
Iannis Xenakis, Curtis Roads, Barry Truax, Douglas Jones and Thomas Parks.
Xenakis actually completed his granular composition without the aid of
a computer. This was achieved by splicing and rearranging magnetic audio
tape, an even more difficult process (Roads 1996a: 169). Curtis Roads spent
10 years on a number of mainframe computers creating a 10 minute composition
called nscor (Roads 1985: 165-167).
Computers have come
a long way since 1990. They can process data at extremely high speeds.
They are all equipped to perform sound synthesis techniques including sampling
synthesis. They are small enough to use in the home. This step forward
in computer technology has meant that granular synthesis can now be realised
everywhere, including some commercial synths. As people come to learn about
granular synthesis techniques there is a growing understanding and popularity
of it's usefulness.
