Audio and Hi-Fi Handbook

454 Pages·1998·4.73 MB·English

by  Ian Sinclair

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Audio and
Hi-Fi Handbook
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Audio and
Hi-Fi Handbook
Third Edition
Editor
IAN R. SINCLAIR
Newnes
OXFORD BOSTON JOHANNESBURG MELBOURNE NEW DELHI SINGAPORE
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Newnes
An imprint of Butterworth-Heinemann
Linacre House, Jordan Hill, Oxford OX2 8DP
225 Wildwood Avenue, Woburn, MA 01801–2041
A division of Reed Educational and Professional Publishing Ltd
A member of the Reed Elsevier plc group
First published as Audio Electronics Reference Book
by BSP Professional Books 1989
Second edition published by Butterworth-Heinemann 1993
Paperback edition 1995
Third edition 1998
© Reed Educational and Professional Publishing 1998
All rights reserved. No part of this publication
may be reproduced in any material form (including
photocopying or storing in any medium by electronic
means and whether or not transiently or incidentally
to some other use of this publication) without the
written permission of the copyright holder except in
accordance with the provisions of the Copyright,
Designs and Patents Act 1988 or under the terms of a
licence issued by the Copyright Licensing Agency Ltd,
90 Tottenham Court Road, London, England W1P 9HE.
Applications for the copyright holder’s written
permission to reproduce any part of this publication
should be addressed to the publishers
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library.
ISBN 0 7506 3636 X
Library of Congress Cataloguing in Publication Data
A catalogue record for this book is available from the Library of Congress.
Typeset by Jayvee, Trivandrum, India
Printed and bound in Great Britain by Clays Ltd, St Ives plc
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This book is dedicated to the memory of
Fritz Langford-Smith,
Mentor and Friend
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Contents
Preface xi Studio and control room acoustics 33
Chapter 4 Principles of Digital Audio 41
Chapter 1 Sound Waves 1 Allen Mornington-West
Dr W. Tempest
Introduction 41
Pure tones and complex waveforms 1 Analogue and digital 41
Random noise 2 Elementary logic processes 43
Decibels 2 The significance of bits and bobs 44
Sound in rooms 3 Transmitting digital signals 46
Reverberation 4 The analogue audio waveform 47
Reverberation, intelligibility and music 4 Arithmetic 51
Studio and listening room acoustics 4 Digital filtering 54
The ear and hearing 5 Other binary operations 58
Perception of intensity and frequency 6 Sampling and quantising 58
Pitch perception 7 Transform and masking coders 65
Discrimination and masking 7 Bibliography 65
Binaural hearing 8
The Haas effect 8
Distortion 9 Chapter 5 Compact Disc Technology 67
Electronic noise absorbers 12 Ken Clements
References 12
Introduction 67
The compact disc . . . some basic facts 67
The compact disc . . . what information it contains 68
Chapter 2 Microphones 14
Quantisation errors 69
John Borwick
Aliasing noise 69
Error correction 71
Introduction 14
How are the errors corrected? 71
Microphone characteristics 14
Interleaving 72
Microphone types 16
Control word 73
The microphone as a voltage generator 18
Eight to fourteen modulation 74
Microphones for stereo 24
Compact disc construction 74
Surround sound 27
The eight to fourteen modulation process 77
References 27
Coupling bits 77
Pit lengths 77
Sync. word 78
Chapter 3 Studio and Control Room Acoustics 28 Optical assembly 80
Peter Mapp Servo circuits 84
The decoder 86
Introduction 28 Digital filtering and digital to analogue conversion 87
Noise control 28 Bibliography 92
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viii Contents
Chapter 6 Digital Audio Recording 93 Dolby SR 152
John Watkinson Dolby S 155
Bibliography 156
Types of media 93
Recording media compared 96
Some digital audio processes outlined 97 Chapter 9 The Vinyl Disc 157
Hard disk recorders 104 Alvin Goldand DonAldous
The PCM adaptor 105
An open reel digital recorder 106 Introduction 157
Rotary head digital recorders 107 Background 157
Digital compact cassette 110 Summary of major steps and processes 157
Editing digital audio tape 110 The lathe 158
Bibliography 111 Cutting the acetate 158
In pursuit of quality 160
The influence of digital processing 161
Chapter 7 Tape Recording 112 Disc cutting – problems and solutions 161
John Linsley Hood Disc pressing 162
Disc reproduction 163
The basic system 112 Drive systems 163
The magnetic tape 112 Pick-up arms and cartridges 165
The recording process 113 The cartridge/arm combination 165
Sources of non-uniformity in frequency response 114 Styli 167
Record/replay equalisation 116 Specifications 168
Head design 117 Measurement methods 169
Recording track dimensions 120 Maintaining old recordings 169
HF bias 120 References 170
The tape transport mechanism 123
Transient performance 123
Tape noise 124 Chapter 10 Valve Amplifiers 171
Electronic circuit design 125 Morgan Jones
Replay equalisation 127
The bias oscillator 129 Who uses valves and why? 171
The record amplifier 130 Subjectivism and objectivism 172
Recording level indication 131 Fixed pattern noise 172
Tape drive control 131 What is a valve? 172
Professional tape recording equipment 131 Valve models and AC parameters 174
General description 132 Practical circuit examples 176
Multi-track machines 133 Other circuits and sources of information 183
Digital recording systems 134
Recommended further reading 138
Chapter 11 Tuners and Radio Receivers 186
John Linsley Hood
Chapter 8 Noise Reduction Systems 139
David Fisher Background 186
Basic requirements for radio reception 186
Introduction 139 The influence of the ionosphere 187
Non-complementary systems 140 Why VHF transmissions? 188
Complementary systems 142 AM or FM? 189
Emphasis 142 FM broadcast standards 190
Companding systems 143 Stereo encoding and decoding 190
The Dolby A system 147 The Zenith-GE ‘pilot tone’ stereophonic system 190
Telecom C4 148 The BBC pulse code modulation (PCM) programme
dbx 148 distribution system 192
Dolby B 149 Supplementary broadcast signals 195
Dolby C 150 Alternative transmission methods 195
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Contents ix
Radio receiver design 196 Chapter 15 Loudspeakers 276
Circuit design 212 Stan Kelly
New developments 213
Appendix 11.1 BBC transmitted MF and VHF Radiation of sound 276
signal parameters 214 Characteristic impedance 277
Appendix 11.2 The 57 KHz sub-carrier radio Radiation impedance 277
data system (RDS) 214 Radiation from a piston 277
Directivity 277
Sound pressure produced at distance r 277
Chapter 12 Pre-amps and Inputs 215 Electrical analogue 279
John Linsley Hood Diaphragm/suspension assembly 280
Diaphragm size 280
Requirements 215 Diaphragm profile 281
Signal voltage and impedance levels 215 Straight-sided cones 282
Gramophone pick-up inputs 216 Material 283
Input circuitry 217 Soft domes 284
Moving coil PU head amplifier design 219 Suspensions 284
Circuit arrangements 219 Voice coil 285
Input connections 223 Moving coil loudspeaker 285
Input switching 223 Motional impedance 286
References 289
Chapter 13 Voltage Amplifiers and Controls 226 Chapter 16 Loudspeaker Enclosures 290
John Linsley Hood Stan Kelly
Preamplifier stages 226 Fundamentals 290
Linearity 226 Infinite baffle 290
Noise levels 230 Reflex cabinets 292
Output voltage characteristics 230 Labyrinth enclosures 295
Voltage amplifier design techniques 231 Professional systems 296
Constant-current sources and ‘current mirrors’ 232 Networks 296
Performance standards 235 Components 298
Audibility of distortion components 237 Ribbon loudspeaker 298
General design considerations 239 Wide range ribbon systems 299
Controls 240 Pressure drive units 300
Electrostatic loudspeakers (ESL) 303
Chapter 14 Power Output Stages 252
Chapter 17 Headphones 310
John Linsley Hood
Dave Berriman
Valve-operated amplifier designs 252
A brief history 310
Early transistor power amplifier designs 253
Pros and cons of headphone listening 310
Listener fatigue and crossover distortion 253
Headphone types 311
Improved transistor output stage design 255
Basic headphone types 314
Power MOSFET output devices 255
Measuring headphones 316
Output transistor protection 258
The future 317
Power output and power dissipation 259
General power amplifier design considerations 261
Slew-rate limiting and transient intermodulation Chapter 18 Public Address and Sound
distortion 262 Reinforcement 319
Advanced amplifier designs 263 Peter Mapp
Alternative design approaches 269
Contemporary amplifier design practice 272 Introduction 319
Sound quality and specifications 274 Signal distribution 319
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x Contents
Loudspeakers for public address and sound Resistance and electrical effects of current 381
reinforcement 322 Capacitive effects 383
Cone driver units/cabinet loudspeakers 322 Magnetic effects 384
Loudspeaker systems and coverage 325 Characteristic impedance 387
Speech intelligibility 328 Reactive components 388
Signal (time) delay systems 330 Interconnection techniques 390
Equalisers and sound system equalisation 332 Connectors 397
Compressor-limiters and other signal processing
equipment 333
Amplifiers and mixers 334 Chapter 22 NICAM Stereo and Satellite Radio
Cinema systems and miscellaneous applications 335 Systems 404
References and bibliography 336 Geoff Lewis
Chapter 19 In-Car Audio 337 The signal structure of the NICAM-728 system 404
Dave Berriman The NICAM-728 receiver 406
The DQPSK decoder 407
Modern car audio 337 Satellite-delivered digital radio (ASTRA digital
FM car reception 337 radio ADR) 407
Power amplifiers 338 Coded orthogonal frequency division multiplex
Separate power amps 339 (COFDM) 411
Multi-speaker replay 340 The JPL digital system 413
Ambisonics 340 Reality of digital sound broadcasting 414
Cassette players 341
Compact disc 343
Digital audio tape 344 Chapter 23 Modern Audio and Hi-Fi Servicing 415
Loudspeakers 345 Nick Beer
Installation 352
The future for in-car audio 360 Mechanism trends 415
Circuit trends 417
Chapter 20 Sound Synthesis 362 Tuners 418
Mark Jenkins Power supplies 418
System control 419
Electronic sound sources 362 Microprocessors 419
Synthesizers, simple and complex 362 Amplifiers 419
Radiophonics and sound workshops 363 Discrete output stage failures 422
Problems of working with totally artificial Digital signal processing 423
waveforms 366 Mini-disc 423
Computers and synthesizers (MIDI and MSX) 368 Test modes 424
Mode messages 373 Surface mounted and VLSI devices 424
Real time 376 Obsolete formats 425
References 377 Software problems 425
Good servicing practice 426
Chapter 21 Interconnections 378 Test equipment 426
Allen Mornington-West Conclusion 426
Target and scope of the chapter 378 Index 427
Basic physical background 378