Fast Additive Synthesis
- 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 ~$7000
- Over a thousand partials plus noise on high-end workstation ~$20,000
- Scalable from $1000 embedded system to $300,000 multiprocessor without
custom hardware.
- Tight integration of control structure computations
- Compares well with previous methods:
Who
| What | When | Partials
| Fs | Freq. Control | Amp.
Control |
Thaddeus Cahill | Telharmonium
| 1897 | ? | Fixed
| . | . |
DiGiugno | 4A |
1976 | 256 | 8kHz
| . | linear (4kHz) |
Baudot
& Freed | Reson8 | 1988 | 350
| 22kHz | Fixed | Exponential
Decay |
Freed & Rodet | FFT-1
on SGI | 1995 | 400 |
44.1kHz | Variable | Linear breakpoint
|
The additive synthesis demonstration includes independent manipulation of
tempo and pitch and artifact free brick wall fixed and tracking filters.