Architectural Acoustics

433 Pages·2007·46.74 MB·English

by  M. David Egan

Architectural
Acoustics
J. Ross Publishing; All Rights Reserved
Classics
TITLES IN THE SERIES
Architectural Acoustics
M. David Egan
ISBN 13: 978-1-932159-78-3, ISBN 10: 1-932159-78-9, 448 pages
Earth Anchors
By Braja M. Das
ISBN 13: 978-1-932159-72-1, ISBN 10: 1-932159-72-X, 242 pages
Limit Analysis and Soil Plasticity
By Wai-Fah Chen
ISBN 13: 978-1-932159-73-8, ISBN 10: 1-932159-73-8, 638 pages
Plasticity in Reinforced Concrete
By Wai-Fah Chen
ISBN 13: 978-1-932159-74-5, ISBN 10: 1-932159-74-6, 474 pages
Plasticity for Structural Engineers
By Wai-Fah Chen & Da-Jian Han
ISBN 13: 978-1-932159-75-2, ISBN 10: 1-932159-75-4, 606 pages
Theoretical Foundation Engineering
By Braja M. Das
ISBN 13: 978-1-932159-71-4, ISBN 10: 1-932159-71-1, 440 pages
Theory of Beam-Columns,Volume 1: Space Behavior and Design
By Wai-Fah Chen & Toshio Atsuta
ISBN 13: 978-1-932159-77-6, ISBN 10: 1-932159-77-0, 732 pages
Theory of Beam-Columns,Volume 2: In-Plane Behavior and Design
By Wai-Fah Chen & Toshio Atsuta
ISBN 13: 978-1-932159-76-2, ISBN 10: 1-932159-76-9, 513 pages
J. Ross Publishing; All Rights Reserved
Architectural
Acoustics
by M. David Egan
J. Ross Publishing; All Rights Reserved
Copyright ©2007 by M.David Egan
ISBN-10:1-932159-78-9
ISBN-13:978-1-932159-78-3
Printed and bound in the U.S.A.Printed on acid-free paper
10 9 8 7 6 5 4 3 2 1
This J.Ross Publishing edition,first published in 2007,is an unabridged republication of the work originally
published by McGraw-Hill,1988.
Library ofCongress Cataloging-in-Publication Data
Egan,M.David.,1941-
Architectural acoustics / by M.David Egan.
p.cm.
Reprint.Originally published:New York :McGraw-Hill,c1988.
Includes bibliographical references and index.
ISBN-10:1-932159-78-9 (pbk :alk.paper)
ISBN-13:978-1-932159-78-3(pbk :alk.paper)
1. Acoustical engineering.2. Architectural acoustics. I.Title.
TA365.E33 2007
729'.29—dc22 2006101133
This publication contains information obtained from authentic and highly regarded sources.Reprinted material
is used with permission,and sources are indicated.Reasonable effort has been made to publish reliable data and
information,but the author and the publisher cannot assume responsibility for the validity ofall materials or for
the consequences oftheir use.
All rights reserved.Neither this publication nor any part thereof may be reproduced,stored in a retrieval
system,or transmitted in any form or by any means,electronic,mechanical,photocopying,recording or other-
wise,without the prior written permission ofthe publisher.
The copyright owner’s consent does not extend to copying for general distribution for promotion,for cre-
ating new works,or for resale.Specific permission must be obtained from J.Ross Publishing for such purposes.
Direct all inquiries to J.Ross Publishing,Inc.,5765 N.Andrews Way,Fort Lauderdale,FL 33309.
Phone:[phone]
Fax:[phone]
Web:www.jrosspub.com
J. Ross Publishing; All Rights Reserved
Jennie E. Brown
(1887-1966)
J. Ross Publishing; All Rights Reserved
J. Ross Publishing; All Rights Reserved
About the Author
M. David Egan, P.E., is a consultant in acoustics and part-time professor at
the College of Architecture, Clemson University. He has worked as a con
sultant in acoustics for Bolt Beranek and Newman (BBN) in Cambridge,
Massachusetts, and has been principal consultant of his own firm in
Anderson, South Carolina for over 15 years. His firm has consulted on over
400 building projects in the United States and abroad. A graduate of Lafay
ette College (B.S.) and the Massachusetts Institute of Technology (M.S.),
where he studied acoustics under the late Professor Robert B. Newman, Pro
fessor Egan also has taught at Tulane University, Georgia Institute of Tech
nology, University of North Carolina at Charlotte, and Washington University
(St. Louis), and has lectured at numerous schools of design. He is the
author of several books in the area of architectural technologies, including
Concepts in Architectural Acoustics (McGraw-Hill, "[97 2), Concepts in Thermal
Comfort (Prentice-Hall, 1975), Concepts in Building Firesafety (Wiley-lnter-
science, 1978 and Kajima Institute, Tokyo, 1981), and Concepts in Architec
tural Lighting (McGraw-Hill, 1983). In addition to consulting, teaching, and
writing. Professor Egan is a fellow of the Acoustical Society of America
(ASA), former director and two-term vice president of the National Council
of Acoustical Consultants (NCAC), associate editor for NOISE/NEWS pub
lished by the Institute of Noise Control Engineering (INCE), and national
awards coordinator for The Robert Bradford Newman Student Award Fund,
Lincoln Center, Massachusetts.
VII
J. Ross Publishing; All Rights Reserved
J. Ross Publishing; All Rights Reserved
Contents
Foreword xiii Reverberation Time 62
Preface XV Optimum Reverberation Time 64
Acknowledgements xvii Example Problem (Reverberation Time) 65
Introduction xix How to Compute Surface Areas 67
Room Noise Reduction 69
Chapter 1: BASIC THEORY 1 Example Problem (Room Noise Reduction) 70
Sound and Vibration 2 Noise Reduction for High-Noise Environments 72
Frequency of Sound 4 Transondent Facings 74
Wavelength 5 Perforated Facings 75
Sound Spectrum 6 Protective Facings for Wall Absorption 77
Velocity of Sound 7 Resonant Panels 78
Frequency Ranges of Audible Sounds 8 Suggested Sound-Absorbing Treatment for Rooms 79
Sensitivity of Hearing 9 Checklist for Effective Absorption of Sound 80
Inverse-Square Law 10
Decibels 12 Chapter 3: ROOM ACOUSTICS 81
Common Sounds in Decibels 13 Ancient Theaters 82
Noise Reduction with Distance 14 Directivity Contours for Speech 83
Logarithms Made Easy 15 Audience Seating 84
Example Problem (Inverse-Square Law) 19 Sight Line Basics 85
Changes in Sound Level 21 Sight Line Layouts 86
Example Problem (Music Man) 22 Checklist for Lecture Rooms 88
Decibel Addition 23 Reflection, Diffusion, and Diffraction 89
Human Ear 25 Wavelength and Frequency for Sound in Air 91
Noise Exposure Limits 27 Pattern of Reflected Sound 93
Loudness Perception 29 Ray Diagrams 95
Sound Level Meters 30 Ray-Diagram Graphics 97
A-Weighted Sound Levels 31 Sound Paths in Auditoriums 98
Sound Spectra for Common Noises 33 Ceilings 100
Noise Level Data 34 Echoes 101
Decibel Scales for Sound Intensity, Pressure, and Power 36 Echo Control Principles 102
Rear-Wall Echo Control Treatment 104
Chapter 2: SOUND ABSORPTION 37 Side Walls 105
Sound-Absorbing Treatment 38 Patterns of Reverberant Decay 108
Noise Reduction Outdoors and Within Enclosures 39 Articulation Index 110
Effect of Adding Sound-Absorbing Treatment to Rooms 41 Flutter Echo 112
Sound Absorption Coefficient 42 Small Rooms 113
Reverberation Rooms 44 Concave Surfaces 115
Effect of Thickness on Absorption Efficiency 46 Sound Reflectors 117
Relative Efficiency of Sound Absorbers 47 Checklist for Worship Spaces 119
Noise Reduction Coefficient 50 Air Absorption 123
Example Problem (NRC Computation) 51 Checklist for Multipurpose Auditoriums 124
Sound Absorption Data for Common Building Materials How to Compute Cubic Volume 127
and Furnishings 52 Example Problem (Volume Computation) 129
Laboratory Test Mountings 55 Example Problem (Reverberation Times) 131
Prefabricated Sound-Absorbing Materials 57 Optimum Reverberation Time 133
Area Effect for Spaced Sound Absorbers 59 Variable Sound Absorbers 134
Suspended Sound-Absorbing Panels and Units 60 Variable Volume Examples 136
Applications for Sound-Absorbing Materials 61 Basic Theater Stages 138
IX
J. Ross Publishing; All Rights Reserved