Table Of Content

Audio Engineering The Newnes Know It All Series PIC Microcontrollers: Know It All Lucio Di Jasio, Tim Wilmshurst, Dogan Ibrahim, John Morton, Martin Bates, Jack Smith, D.W. Smith, and Chuck Hellebuyck ISBN: 978-0-7506-8615-0 Embedded Software: Know It All Jean Labrosse, Jack Ganssle, Tammy Noergaard, Robert Oshana, Colin Walls, Keith Curtis, Jason Andrews, David J. Katz, Rick Gentile, Kamal Hyder, and Bob Perrin ISBN: 978-0-7506-8583-2 Embedded Hardware: Know It All Jack Ganssle, Tammy Noergaard, Fred Eady, Lewin Edwards, David J. Katz, Rick Gentile, Ken Arnold, Kamal Hyder, and Bob Perrin ISBN: 978-0-7506-8584-9 Wireless Networking: Know It All Praphul Chandra, Daniel M. Dobkin, Alan Bensky, Ron Olexa, David A. Lide, and Farid Dowla ISBN: 978-0-7506-8582-5 RF & Wireless Technologies: Know It All Bruce Fette, Roberto Aiello, Praphul Chandra, Daniel Dobkin, Alan Bensky, Douglas Miron, David Lide, Farid Dowla, and Ron Olexa ISBN: 978-0-7506-8581-8 Electrical Engineering: Know It All Clive Maxfi eld, Alan Bensky, John Bird, W. Bolton, Izzat Darwazeh, Walt Kester, M.A. Laughton, Andrew Leven, Luis Moura, Ron Schmitt, Keith Sueker, Mike Tooley, D.F. Warne, and Tim Williams ISBN: 978-1-85617-528-9 Audio Engineering: Know It All Douglas Self, Richard Brice, Ben Duncan, John Linsley Hood, Ian Sinclair, Andrew Singmin, Don Davis, Eugene Patronis, and John Watkinson ISBN: 978-1-85617-526-5 Circuit Design: Know It All Darren Ashby, Bonnie Baker, Stuart Ball, John Crowe, Barrie Hayes-Gill, Ian Grout, Ian Hickman, Walt Kester, Ron Mancini, Robert A. Pease, Mike Tooley, Tim Williams, Peter Wilson, and Bob Zeidman ISBN: 978-1-85617-527-2 Test and Measurement: Know It All Jon Wilson, Stuart Ball, G.M.S de Silva, Tony Fischer-Cripps, Dogan Ibrahim, Kevin James, Walt Kester, Michael Laughton, Chris Nadovich, Alex Porter, Ed Ramsden, Steve Scheiber, Douglas Warne, and Tim Williams ISBN: 978-1-85617-530-2 Wireless Security: Know It All Praphul Chandra, Alan Bensky, Tony Bradley, Chris Hurley, Steve Rackley, James Ransome, John Rittinghouse, Timothy Stapko, George Stefanek, Frank Thornton, and Jon Wilson ISBN: 978-1-85617-529-6 For more information on these and other Newnes titles visit: Audio Engineering Douglas Self Richard Brice Ben Duncan John Linsley Hood Ian Sinclair Andrew Singmin Don Davis Eugene Patronis John Watkinson AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK • OXFORD PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Newnes is an imprint of Elsevier Newnes is an imprint of Elsevier 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA Linacre House, Jordan Hill, Oxford OX2 8DP, UK Copyright © 2009, Elsevier Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone: ((cid:2) 44) 1865 843830, fax: ( (cid:2) 44) 1865 853333, E-mail: [email protected]. You may also complete your request online via the Elsevier homepage (http://elsevier.com), by selecting “ Support & Contact ” then “ Copyright and Permission ” and then “ Obtaining Permissions. ” (cid:2)(cid:4) Recognizing the importance of preserving what has been written, Elsevier prints its books on acid-free paper whenever possible. Library of Congress Cataloging-in-Publication Data Audio engineering : know it all / by Ian Sinclair … [et al.]. p. cm. Includes bibliographical references and index. ISBN 978-1-85617-526-5 (alk. paper) 1. Sound—Recording and reproducing—Handbooks, manuals, etc. 2. Sound—Recording and reproducing—Digital techniques—Handbooks, manuals, etc. I. Sinclair, Ian Robertson. TK7881.4.A9235 2008 621.389(cid:3)3—dc22 2008033305 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN: 978-1-85617-526-5 For information on all Newnes publications v isit our Web site at www.books.elsevier.com Typeset by Charon Tec Ltd., A Macmillan Company (www.macmillansolutions.com) 09 10 11 12 13 14 15 16 5 4 3 2 1 Printed in The United States of America Contents About the Authors .............................................................................................................xv I: Fundamentals of Sound ..................................................................................................1 Chapter 1: Audio Principles ...............................................................................................3 1.1 The Physics of Sound ................................................................................................3 1.2 Wavelength ................................................................................................................4 1.3 Periodic and Aperiodic Signals .................................................................................5 1.4 Sound and the Ear ......................................................................................................6 1.5 The Cochlea ...............................................................................................................9 1.6 Mental Processes .....................................................................................................11 1.7 Level and Loudness .................................................................................................14 1.8 Frequency Discrimination........................................................................................16 1.9 Frequency Response and Linearity ..........................................................................20 1.10 The Sine Wave .........................................................................................................22 1.11 Root Mean Square Measurements ...........................................................................25 1.12 The Decibel ..............................................................................................................26 1.13 Audio Level Metering ..............................................................................................30 References ................................................................................................................32 Chapter 2: Measurement ..................................................................................................33 2.1 Concepts Underlying the Decibel and its Use in Sound Systems ...........................33 2.2 Measuring Electrical Power .....................................................................................38 2.3 Expressing Power as an Audio Level ......................................................................39 2.4 Conventional Practice ..............................................................................................40 2.5 The Decibel in Acoustics—L ,L , and L ..............................................................42 P W I 2.6 Acoustic Intensity Level (L), Acoustic Power Level (L ), I W and Acoustic Pressure Level (L ) ............................................................................44 P 2.7 Inverse Square Law ..................................................................................................46 2.8 Directivity Factor .....................................................................................................47 vi Contents 2.9 Ohm’s Law ..............................................................................................................47 2.10 A Decibel is a Decibel is a Decibel .........................................................................48 2.11 Older References .....................................................................................................48 2.12 The Equivalent Level (L ) in Noise Measurements ..............................................51 EQ 2.13 Combining Decibels ................................................................................................54 2.14 Combining Voltage ..................................................................................................58 2.15 Using the Log Charts ...............................................................................................58 2.16 Finding the Logarithm of a Number to Any Base ...................................................60 2.17 Semitone Intervals ...................................................................................................61 2.18 System Gain Changes ..............................................................................................62 2.19 The VU and the Volume Indicator Instrument ........................................................62 2.20 Calculating the Number of Decades in a Frequency Span ......................................68 2.21 Defl ection of the Eardrum at Various Sound Levels ...............................................69 2.22 The Phon ..................................................................................................................70 2.23 The Tempered Scale ................................................................................................73 2.24 Measuring Distortion ...............................................................................................73 2.25 The Acoustical Meaning of Harmonic Distortion ...................................................74 2.26 Playback Systems in Studios ...................................................................................76 2.27 Decibels and Percentages ........................................................................................77 2.28 Summary .................................................................................................................79 Further Reading .......................................................................................................79 Chapter 3: Acoustic Environment ....................................................................................81 3.1 The Acoustic Environment ......................................................................................81 3.2 Inverse Square Law .................................................................................................82 3.3 Atmospheric Absorption .........................................................................................84 3.4 Velocity of Sound ....................................................................................................85 3.5 Temperature-Dependent Velocity ............................................................................88 3.6 The Effect of Altitude on the Velocity of Sound in Air ..........................................88 3.7 Typical Wavelengths ................................................................................................89 3.8 Doppler Effect .........................................................................................................90 3.9 Refl ection and Refraction ........................................................................................91 3.10 Effect of a Space Heater on Flutter Echo ................................................................92 3.11 Absorption ...............................................................................................................94 3.12 Classifying Sound Fields .........................................................................................97 Contents vii 3.13 The Acoustic Environment Indoors ......................................................................102 3.14 Conclusion ............................................................................................................112 Further Reading.....................................................................................................113 II: Audio Electronics .......................................................................................................115 Chapter 4: Components ..................................................................................................117 4.1 Building Block Components .................................................................................117 Chapter 5: Power Supply Design ....................................................................................139 5.1 High Power Systems .............................................................................................139 5.2 Solid-State Rectifi ers.............................................................................................143 5.3 Music Power..........................................................................................................144 5.4 Infl uence of Signal Type on Power Supply Design ..............................................144 5.5 High Current Power Supply Systems ....................................................................146 5.6 Half-Wave and Full-Wave Rectifi cation ...............................................................147 5.7 Direct Current Supply Line Ripple Rejection .......................................................147 5.8 Voltage Regulator Systems ...................................................................................148 5.9 Series Regulator Layouts ......................................................................................150 5.10 Overcurrent Protection ..........................................................................................152 5.11 Integrated Circuit (Three Terminals) Voltage Regulator ICs ................................153 5.12 Typical Contemporary Commercial Practice ........................................................157 5.13 Battery Supplies ....................................................................................................159 5.14 Switch-Mode Power Supplies ...............................................................................159 Reference ..............................................................................................................159 III: Preamplifi ers and Amplifi ers ...................................................................................161 Chapter 6: Introduction to Audio Amplifi cation............................................................163 Chapter 7: Preamplifi ers and Input Signals ..................................................................167 7.1 Requirements ........................................................................................................167 7.2 Signal Voltage and Impedance Levels ..................................................................167 7.3 Gramophone Pick-Up Inputs ................................................................................169 7.4 Input Circuitry .......................................................................................................171 7.5 Moving Coil Pick-up Head Amplifi er Design ......................................................175 7.6 Circuit Arrangements ............................................................................................176 viii Contents 7.7 Input Connections .................................................................................................183 7.8 Input Switching .....................................................................................................184 7.9 Preamplifi er Stages ...............................................................................................186 7.10 Linearity ................................................................................................................188 7.11 Noise Levels ..........................................................................................................197 7.12 Output Voltage Characteristics ..............................................................................198 7.13 Voltage Amplifi er Design ......................................................................................200 7.14 Constant-Current Sources and “Current Mirrors” ................................................202 7.15 Performance Standards .........................................................................................209 7.16 Audibility of Distortion .........................................................................................212 7.17 General Design Considerations .............................................................................218 7.18 Controls .................................................................................................................219 References .............................................................................................................239 Chapter 8: Interfacing and Processing ..........................................................................241 8.1 The Input ...............................................................................................................241 8.2 Radio Frequency Filtration ...................................................................................252 8.3 Balanced Input ......................................................................................................253 8.4 Subsonic Protection and High-Pass Filtering ........................................................257 8.5 Damage Protection ................................................................................................263 8.6 What Are Process Functions? ...............................................................................267 8.7 Computer Control .................................................................................................278 References .............................................................................................................280 Chapter 9: Audio Amplifi ers ...........................................................................................283 9.1 Junction Transistors ..............................................................................................283 9.2 Control of Operating Bias .....................................................................................286 9.3 Stage Gain .............................................................................................................288 9.4 Basic Junction Transistor Circuit Confi gurations .................................................289 9.5 Emitter–Follower Systems ....................................................................................291 9.6 Thermal Dissipation Limits ..................................................................................294 9.7 Junction Field Effect Transistors (JFETs) ............................................................295 9.8 Insulated Gate FETs (MOSFETs) .........................................................................299 9.9 Power BJTs vs Power MOSFETs as Amplifi er Output Devices ..........................303 9.10 U and D MOSFETs ...............................................................................................305 9.11 Useful Circuit Components ...................................................................................307 Contents ix 9.12 Circuit Oddments ..................................................................................................309 9.13 Slew Rate Limiting ...............................................................................................311 References .............................................................................................................312 Chapter 10: Audio Amplifi er Performance ....................................................................313 10.1 A Brief History of Amplifi ers ...............................................................................313 10.2 Amplifi er Architectures.........................................................................................314 10.3 The Three-Stage Architecture ...............................................................................314 10.4 Power Amplifi er Classes .......................................................................................317 10.5 AC- and DC-Coupled Amplifi ers ..........................................................................325 10.6 Negative Feedback in Power Amplifi ers ...............................................................330 References .............................................................................................................334 Chapter 11: Valve (Tube-Based) Amplifi ers ...................................................................337 11.1 Valves or Vacuum Tubes .......................................................................................337 11.2 Solid-State Devices ...............................................................................................349 11.3 Valve Audio Amplifi er Layouts ............................................................................350 11.4 Single-Ended Versus Push–Pull Operation ...........................................................352 11.5 Phase Splitters .......................................................................................................355 11.6 Output Stages ........................................................................................................358 11.7 Output (Load-Matching) Transformer ..................................................................360 11.8 Effect of Output Load Impedance .........................................................................364 11.9 Available Output Power ........................................................................................365 References .............................................................................................................366 Chapter 12: Negative Feedback ......................................................................................367 12.1 Amplifi er Stability and Negative Feedback ..........................................................367 12.2 Maximizing Negative Feedback ............................................................................377 12.3 Maximizing Linearity Before Feedback ...............................................................378 Further Reading.....................................................................................................379 Chapter 13: Noise and Grounding .................................................................................381 13.1 Audio Amplifi er Printed Circuit Board Design ....................................................381 13.2 Amplifi er Grounding .............................................................................................390 13.3 Ground Loops: How They Work and How to Deal with Them ............................393 13.4 Class I and Class II................................................................................................400 13.5 Mechanical Layout and Design Considerations....................................................401