Granular synthesis

Granular synthesis is a basic sound synthesis method that operates on the microsound time scale. It is often based on the same principles as sampling but often includes analog technology. The samples are not used directly however, they are split in small pieces of around 1 to 50 ms in length, or the synthesized sounds are very short. These small pieces are called grains. Multiple grains may be layered on top of each other all playing at different speed, phase, volume, and pitch.

The result is no single tone, but a soundscape, often a cloud, that is subject to manipulation in a way unlike any natural sound and also unlike the sounds produced by most other synthesis techniques. By varying the waveform, envelope, duration, spatial position, and density of the grains many different sounds can be produced.

The result is usable as music, sound effects or as raw material for further processing by other synthesis or DSP effects. The range of effects that can be produced include amplitude modulation, time stretching, stereo or multichannel scattering, random reordering, disintegration and morphing.

Dennis Gabor researched how human beings communicate and hear. The result of his investigations was the theory of granular synthesis, although Greek composer Iannis Xenakis claimed that he was actually the first inventor of this synthesis technique. Xenakis 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).

Steve Reich has also claimed to use the tool of granular synthesis, particularly in pieces Three Tales, City Life, and an upcoming piece in regard to the 9/11 attacks.

Curtis Roads is often credited as the first person to implement a digital granular synthesis engine. Canadian composer Barry Truax was one of first to implement real-time versions of this synthesis technique.

The Malstrom synthesizer in Propellerhead's Reason virtual music studio employs a technique known as Graintable synthesis. It is a blending of granular synthesis and wavetable synthesis.

Books

• Roads, Curtis (2001). Microsound. Cambridge: MIT Press. ISBN 0-262-18215-7.
• Miranda, E. R. (2002). Computer Sound Design: Synthesis Techniques and Programming. Oxford: Focal Press. ISBN 0-240-51693-1.
• Roads, Curtis (1996). The Computer Music Tutorial. Cambridge: The MIT Press. ISBN 0-252-18158-4. {{cite book}}: Check |isbn= value: checksum (help)
• "Les techniques granulares dans la synthèse sonore by Manuel Rocha Iturbide. Doctoral Thesis. University of Paris VIII, Paris France, 1999.

Examples

Credits and info about the software used.

Articles

• Granular Synthesis by Eric Kuehnl
• "The development of GiST, a Granular. Synthesis Toolkit Based on an Extension of the FOF Generator" by Gerhard Eckel and Manuel Rocha Iturbide
• Searching for a global synthesis technique through a quantum conception of sound by Manuel Rocha Iturbide
• Going with the Grain a review of 10 granular synthesis programs by Dennis Miller (2008)
• Further articles on Granular Synthesis

Further reading

• Digital signal processing
• Micromontage audio montage on the time scale of microsounds
• Granular Synthesis Resource Web Site

Software

• Density Granular Synthesis 1.x Real (Mac/Win)
• MacPOD 2.x Real-time granular synthesizer (Mac OS X)
• WinPOD 2.x Real-time granular synthesizer (Windows XP/Vista)
• RTGS-X Real-Time Granular Synthesizer X (Mac OS X)
• REplay PLAYer generative granular synthesis software by Karlheinz Essl (Mac OS X)
• Kenaxis real-time sample manipulation environment with a powerful granular synthesis engine developed with input from Barry Truax (Mac OS X, Windows)
• Absynth Commercial real-time software synthesizer with graintable synthesis (Windows, Mac OS)
• Granulab real-time granular synthesizer (Windows)
• Chaosynth cellular automata granular synthesizer by Eduardo Reck Miranda (Mac OS X, Windows)
• crusherX-Live! granular synthesis system (Windows)
• WSOLA time scale modification of audio using granular synthesis
• Vocal Modeler special vocal effect for Reaktor that uses granular synthesis (Mac OS X, Windows)
• White FX a granular effect for Reaktor (Mac OS X, Windows)
• AudioMulch a real-time audio processing tool which also offers granular synthesis (Windows)
• Atomic Cloud real-time grain cloud generator (Windows)
• Cecilia / [1] granular synthesis based on CSound (Mac OS, MacOS X, Windows, Linux)
• Reason includes a virtual device called Malström which combines granular and wavetable synthesis techniques (Mac OS X, Windows)
• CDP granular synthesizer from the Composer's Desktop Project of Trevor Wishart et al.
• thOnk_0+2 non-realtime granular synthesis (Mac OS 9)
• ixiQuarks: a live improvisation software suite that contains a few sound granulators (Mac OS X)

Programming Languages

• Csound comprehensive music software including granular synthesis (overview over granular synthesis opcodes)
• SuperCollider programming language for real time audio synthesis
• Reaktor visual programming environment for sampling, granular sampling, sequencing and modular synthesis
• Max/MSP graphical authoring software for real-time audio and video
• Pure Data (Pd) graphical programming language for real-time audio and video
• ChucK audio programming language for real-time audio synthesis
• Real-time Cmix programming language for real-time audio synthesis, including several algorithms for granular synthesis.