Bring Your Own Control to Additive Synthesis
Adrian Freed
Introduction and Overview
- History and Motivation
- Related Work
- Examples of BYO Control Functions
History
- In 1992 I developed the HTM (Hear the Music) software synthesis
system:
- portable
- reactive (real-time)
- efficient unit generator library
- In 1993 Xavier Rodet suggested and guided my implementation of
additive synthesis by IFFT, a method he patented with Phillippe Depalle:
- 10-30 times more efficient than frequency and amplitude interpolated
oscillators
- efficient noise synthesis
- good potential for VLSI implementation
- The resulting additive synthesis system solves many of the difficulties of
previous hardware systems such as the 4A-4X and Reson8:
- Real-time control of hundreds of partials at 44.1kHz on a moderately priced
workstation ~$5000
- Over a thousand partials plus noise on high-end workstation ~$20,000
- Scalable from $300 embedded system to $300,000 multiprocessor without
custom hardware.
- Tight integration of control structure computations
Bring Your Own Control Structures
- BYO control structures are to spectral sound descriptions what unit
generators are for time domain signals.
- BYO is a layer between high level programming tools (such as IRCAM/Opcode's
MAX [Puckette & Zicaralli 90], Matlab, and the Apple Newton) and
interpolated additive synthesis
- BYO controls must be:
- efficient, because they are executed every frame for every
partial
- easy to write, because musicians will always need control functions
that are not already available
Related Work
- Patchwork-Chant (IRCAM Forum), not real-time, but encapsulates many
types of spectral description
- Nyquist (Roger Dannenberg), not real-time, but powerful enough to integrate
spectral descriptions efficiently
Video Demonstration
- Printed proceedings describes technical details of the BYO interface
- The video demonstrates how BYO control functions may be combined and
controlled
Conclusions
Benefits of timbre control by spectral description include:
- Perceptually relevant parameterizations
- Sample rate and hardware independent timbre description (difficult with FM
and physical modelling)
- Extra dimensions for synthesis resource optimization and allocation:
- sample rate (bandwidth)
- temporal and frequency masking
- partial pruning (timbral precision)
- adjustable frame rate (temporal precision)
- partial group assignment accross processors
- arithmetic stability (non-recursive)
Acknowledgments
- Paul Debevec
- Gibson Guitar Company
- Mark Goldstein
- Michael Goodwin
- Mike Lee
- David Petru
- Xavier Rodet
- Silicon Graphics Inc.
- David Wessel
- Matt Wright