granular synthesis: an overview. overview sounds are made up of a large number of particles! ...
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Overview
Sounds are made up of a large number of particles!
Examples of granular sounds
LeavesTraffic
Babbling Brook
History
“All sound is an integration of grains, of elementary sonic particles, of sonic quanta.” – Xenakis 1971
First suggested as a computer music technique by Iannis Xenakis and Curtis Roads
Granular Synthesis particulars
Production of high density of small acoustic events called “GRAINS”
Allows time stretching or compression
Time and/or frequency-based processing
Numerous components in granular synthesis Grain size, type, source, envelope Grain density Temporal arrangement of grains
Grain sources
Granular synthesis can be generated from any sound source
True granular synthesis uses synthetic sound sources Wave table (I.e. sine wave) FM Synthesis
Can also granulate a sampled sound (sometimes called soundfile granulation)
“The Grain”
A “grain” is a slice of sound
Typically less than 50 ms in duration
Usually 10-30ms
Grains < 50ms = continuous texture
Grains > 50ms = discrete events
Grain Envelope
Each grain must have an envelope (ADSR)
Impacts how we perceive the resulting timbre
This is a “Hanning” envelope
Grain Density
How many grain events take place per second
Can range from several hundred to several thousand!
Grains can overlap or be separated by silence
Types of Granular Synthesis
There are three methods of performing granular synthesis: Pitch-synchronous Asynchronous Quasi-synchronous
Pitch-synchronous
Infrequently performed
Uses pitch detection and spectral analysis as a means to determine grains
Asynchronous
“Clouds of grains” or “Sonic Spray Gun”
Random distribution of grains over some period of time
Algorithms determined grain placement
Results in organic and complex timbres