Table Of Contentcomputer music D
Designing Sound e
Andy Farnell s
i
Designing Sound teaches students and professional sound designers to understand and create sound effects g
starting from nothing. Its thesis is that any sound can be generated from first principles, guided by analysis n
and synthesis. The text takes a practitioner’s perspective, exploring the basic principles of making ordinary,
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everyday sounds using an easily accessed free software. Readers use the Pure Data (Pd) language to construct
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sound objects, which are more flexible and useful than recordings. Sound is considered as a process, rather than
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as data—an approach sometimes known as “procedural audio.” Procedural sound is a living sound effect that
can run as computer code and be changed in real time according to unpredictable events. Applications include
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video games, film, animation, and media in which sound is part of an interactive process.
The book takes a practical, systematic approach to the subject, teaching by example and providing back- o
ground information that offers a firm theoretical context for its pragmatic stance. Many of the examples follow
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a pattern, beginning with a discussion of the nature and physics of a sound, proceeding through the develop-
ment of models and the implementation of examples, to the final step of producing a Pure Data program for n
Designing Sound
the desired sound. Different synthesis methods are discussed, analysed, and refined throughout. After master- d
ing the techniques presented in Designing Sound, students will be able to build their own sound objects for use
in interactive applications and other projects.
Andy Farnell has a degree in Computer Science and Electronic Engineering from University College London and
now specializes in digital audio signal processing. He has worked as a sound effects programmer for BBC radio
and television and as a programmer on server-side applications for product search and data storage.
“A monumental work. This surely has the potential of becoming the sound designer’s bible!”
—Kees van den Doel, Scientific Computing Laboratory, University of British Columbia
“An excellent, practical introduction to sound synthesis methods. The most useful resource on Pure Data that F
I’ve come across. Essential reading for anyone wanting to learn how to create sounds.” a
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—Karen Collins, Canada Research Chair in Interactive Audio, University of Waterloo n
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“Putting the creativity of every single sonic nuance in the hands of the sound designer—and the listener—is l
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the gift that Farnell brings through his book Designing Sound. What an empowering experience!”
—David Sonnenschein, Director, Musician, and author of Sound Design: The Expressive Power of Music, Voice,
and Sound Effects in Cinema
“Andy Farnell’s Designing Sound is a fantastic and incredibly inspiring book. With hundreds of fully working
sound models, this ‘living document’ helps students to learn with both their eyes and their ears, and to explore
what they are learning on their own computer. Perfectly balanced between theory and practice, the book will
help students and professionals alike to develop and refine the skills and understanding that they require to
synthesize the worlds of sounds around them and the sounds in the imagined worlds of advertising, TV, film,
computer games, and their own original audio art. A great textbook, a great workbook, a great way to actually
learn how to design sounds—I can’t wait to use Designing Sound in my classes.”
—Richard Boulanger, Professor of Electronic Production and Design, Berklee College of Music
The MIT Press Andy Farnell
Massachusetts Institute of Technology
Cambridge, Massachusetts 02142
http://mitpress.mit.edu
978-0-262-01441-0
Designing Sound
Designing Sound
Andy Farnell
TheMITPress
Cambridge,Massachusetts
London,England
(cid:1)c 2010AndyFarnell
Allrightsreserved.Nopartofthisbookmaybereproducedinanyformbyanyelectronicor
mechanical means (includingphotocopying, recording, orinformationstorage andretrieval)
withoutpermissioninwritingfromthepublisher.
Forinformationaboutspecialquantitydiscounts,pleaseemailspecial [email protected]
ThisbookwassetinCenturybyWestchester BookComposition.
PrintedandboundintheUnitedStates ofAmerica.
LibraryofCongressCataloging-in-PublicationData
Farnell,Andy,1969–.
Designingsound/AndyFarnell.
p. cm.
Includes bibliographicalreferencesandindex.
ISBN978-0-262-01441-0 (hardcover :alk.paper)
1. Computersoundprocessing. 2. Sound—Recordingandreproducing—Digital
techniques. 3. Sounds. 4. Motionpictures—Soundeffects. 5. Animatedfilms—Sound
effects. 6. Videogames—Soundeffects. I. Title.
TK7881.4.F365 2010
006.5—dc22
2009050741
10 9 8 7 6 5 4 3 2 1
To Kate
Contents
Acknowledgements xxiii
1 Introduction 1
I Theory 5
2 Theory Introduction 7
3 Physical Sound 9
3.1 Elementary Physics 9
Energy 9
Force 9
Pressure 9
Work 10
Systems 10
Power 10
Energy Sources 10
Matter and Mass 11
Force, Distance, and Acceleration 11
Displacement, Movement, and Freedom 12
Excitation 12
3.2 Materials 12
Elasticity and Restoration 13
Density 15
Plasticity 16
Structure and Strength 17
3.3 Waves 17
Wave Models 17
Exchange of Forces 18
Propagation 19
Wave Types 20
Amplitude 20
Speed 21
Group and Phase Velocity 22
Wavelength 23
Frequency and Period 23
Simple Wave Math 23
Phase 24
Superposition and Phase Cancellation 24
3.4 Boundaries 25
Phase of Bending Waves at Solid Boundaries 26
Coupling 28
Reflection and Standing Waves 28
Modes 29
Visualising Sound Waves 30
Shape 30
Entropy and Heat 31
Loss and Damping 31
3.5 Analogues 32
Potential 32
Energy Inlet 33
Flow 33
Resistance 33
Tap or Outlet 34
Capacitance 34
Example Network Analogy 35
Example System Analysis 36
Acknowledgements 37
References 37
4 Oscillations 39
4.1 Oscillators 39
Period and Frequency 39
Frequency of a Spinning Object 39
Relaxation 41
Frequency of Relaxation Systems 42
Quantisation 43
4.2 Simple Harmonic Oscillators 43
Frequency of a Mass on Spring 44
Frequency of a Pendulum 46
Frequency of an LC Network 46
4.3 Complex Harmonic Oscillators 48
Oscillation of a String 48
Oscillation of a Bar or Rod 49
Oscillation of Cones, Membranes, Laminas 50
4.4 Driven Oscillations and Resonance 51
References 53
5 Acoustics 55
5.1 Acoustic Systems 55
Vibrations in Air 55
Radiation 56
Radiation Patterns 56
Spherical, Cylindrical, and Planar Waves 57
5.2 Intensity and Attenuation 58
Sound Pressure Level 58
Position and Correlation 58
Acoustic Sound Intensity 59
Geometric Attenuation 60
Transmission and Absorption 61
5.3 Other PropagationEffects 62
Reflection 62
Scattering 62
Dispersion 63
Refraction 63
Diffraction 64
Diffusion 65
Ground Effects 66
Oblique Boundary Loss 66
Wind Shear 67
Aberration 67
The Doppler Effect 67
Room Acoustics 67
Reverb Time 68
Outdoor Acoustics 70
5.4 Acoustic Oscillations 70
Turbulence 70
Reynolds Number 71
Sounds of Turbulence 71
Pipes 71
Radiation from Pipes and Horns 73
Helmholtz Oscillator 73
Textbooks 74
Papers 74
Online Resources 74
6 Psychoacoustics 77
6.1 Perceiving Sounds 77
Ears 77
Frequency Range of Human Hearing 78
Nonlinearity 78
Threshold of Hearing 78
Just Noticeable Difference 79
Localisation 79
Interaural Time Difference 79
Interaural Intensity Difference 80
Head Response Transfer Function 80
Distance 80
