Main Group 45: FOF Synthesis


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01 FOF Tutorial
1 minimum instrument
2 LINSEG amplitude envelope
3 exaggerated vibrato
4 moving from granular texture to timbre
5 octaviation coefficient
6 striated formant frequency
6B smooth formant frequency
6C FM modulated formant frequency
7 rise of granules
8 middle decay of granules
9 decay of granules
10 duration and decay of granules
11 rise and middle decay: band- and skirtwidth
33 Summed FOF Generators
1 aaah...

Overview

Designed in the first place for rich vocal imitation, and developed from the CHANT program, the FOF unit generator produces a complex, periodic signal with one spectral formant region.

FOF's model is closely related to the source/filter paradigm of natural instruments and the voice: a complex source is amplified by a complex resonator. On the other hand, FOF produces series of very short, often overlapping excitations, that can be considered to be granules. (Clarke, J.M. 1988)


Suggested Reading

Bennet, G. 1981.
"Singing Synthesis in Electronic Music."
In Research Aspects of Singing, ed. J. Sundberg.
Publication 33. Stockholm: Royal Swedish Academy of Music, pp. 34-50.

Bennet, Gerald and Xavier Rodet. 1989.
"Synthesis of the Singing Voice."
in Mathews, M.V. and J.R. Pierce, eds.1989.
Current Directions in Computer Music Research.
MIT press, pp. 19-44.

Clarke, J.M, P.D. Manning, R. Berry and A. Purvis. 1988.
"VOCEL: New Implementations of the FOF Synthesis Method."
Proceedings of the 1988 International Computer Music Conference.
San Francisco: International Computer Music Association.

Clarke, J.M. 1988.
"FOF Synthesis on the Atari ST."
in FOF Manual, Appendix 1.
York, England: Composers' Desktop Project, pp. 8-14.

Clarke, J.M. 1989.
"An FOF Synthesis Tutorial."
in Csound Manual, Appendix 3.
Available via anonymous ftp from cecelia.media.mit.edu:
pub/Csound/csbeta/csman.ps.Z of feb 5, 1993, pp. 114-117.

Rodet, X. 1984.
"Time-Domain Formant-Wave-Function Synthesis."
Computer Music Journal 8(3):9-14.

Rodet, X., Yves Potard, and Jean-Baptiste Barrière. 1984.
"The CHANT Project: From the Synthesis of the Singing Voice to
Synthesis in General."
Computer Music Journal 8(3):15-31.

Sundberg, J. 1975.
"Formant Technique in a Professional Female Singer."
Acustica 32:89-96.

Sundberg, J. 1978.
"Synthesis of Singing."
Swedish Journal of Musicology 60(1):107-112.

Sundberg, J. 1979.
"On Coupling between Vocal Tract and Voice Source."
Rapports IRCAM, Vol. 21.

Sundberg, J. 1979.
"Chest Vibrations in Singers."
Rapports IRCAM, Vol. 22.

Sundberg, J. 1987.
The Science of the Singing Voice.
Dekalb, IL: Northern Illinois University Press, 216 pp.

Zera, J., J. Gauffin and J. Sundberg. 1984.
"Synthesis of Selected VCV-Syllables in Singing."
Proceedings of the 1984 International Computer Music Conference.
San Francisco: International Computer Music Association.


FOF Tutorial

Sub group 01 holds all of the FOF tutorial instruments. Please refer to Appendix 4 of the Csound manual for a detailed discussion of these instruments. (Vercoe 1993b: pp. 114-117)

Please note:
The FOF unit generator has been subject to changes in the last years. In the FOF group below, we use the currently valid input parameters, as described in the Csound manual of 1993. Earlier versions of the Csound manual should not be used aside with these instruments!


45_01_1

additional parameters: none

This is the minimum FOF configuration with some ordinary parameter values

[flowchart]

Orchestra and Score

WAV and mp3


45_01_2

additional parameters: none

A simple amplitude envelope applied to FOF.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_3

additional parameters:

This design shows how to add an exaggerated vibrato to the fundamental frequency.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_4

additional parameters:

The design on this page shows a transition from granular texture to timbre, from pulse to pitch. This is achieved by varying the fundamental frequency from 5 Hz to 200 Hz (see below). Long duration of 10 sec is required.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_6B

additional parameters:

Smooth variation of the formant frequency at audio rate.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_6C

additional parameters:

FM modulation of the formant frequency at audio rate.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_7

additional parameters:

Variation of the rise parameter of the granules.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_8

additional parameters:

Variation of the middle decay of the granules. The rate of the build-in exponential decay is controlled by kband. The bigger kband the steeper the decay; zero means no decay.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_9

additional parameters:

Variation of the exponential decay of the granules.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_10

additional parameters:

Variation of duration and exponential decay of successive granules.

[flowchart]

Orchestra and Score

WAV and mp3


45_01_11

additional parameters:

Variation of middle decay and rise of the granules, corresponding to band- and skirtwidth in the spectral domain.

[flowchart]

Orchestra and Score

WAV and mp3


45_33_1

additional parameters:

This instrument synthesizes the vocal [a] for a male person. The four formant peaks (500, 850, 2500 and 3500 Hz) are specified by four FOF generators. Each FOF generator runs at a different amplitude. The result is summed. (Vercoe 1993: testfiles/fof.orc)

[flowchart]

Orchestra and Score

WAV and mp3


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