Audio Engineering Explained

Copyright Page......Page 2
Preface......Page 3
Preface\r......Page 6
Introduction......Page 7
The decibel......Page 8
Frequency......Page 11
Wavelength......Page 14
Superposition......Page 17
Ohm’s law......Page 19
Human hearing......Page 21
Monitoring audio program material......Page 23
The point source......Page 24
The line source......Page 26
Bibliography......Page 27
Preface\r......Page 28
Outer ear function......Page 29
Middle ear function......Page 30
Inner ear function......Page 33
Critical bands......Page 35
Frequency and pressure sensitivity ranges......Page 38
Loudness perception......Page 40
Measuring loudness......Page 42
Loudness of simple sounds......Page 43
Loudness of complex sounds......Page 44
Noise-induced hearing loss......Page 46
Protecting your hearing......Page 48
Interaural time difference (ITD)......Page 50
Interaural intensity difference (IID)......Page 52
ITD and IID trading......Page 54
Stereophonic listening......Page 55
References......Page 57
Preface\r......Page 59
Basic wave generation and transmission......Page 60
Acoustical power......Page 61
The decibel......Page 63
The reverberant field......Page 65
Sound in a plane wave field......Page 67
Effects of humidity on sound transmission......Page 68
Diffraction effects at short wavelengths; directivity index (DI)......Page 70
References......Page 72
Preface\r......Page 73
Powering......Page 74
DC-to-DC conversion......Page 75
Recent developments in phantom powering......Page 76
Power supplies for older tube microphones......Page 79
The microphone output transformer......Page 80
Improper microphone loading......Page 81
Microphone splitters......Page 83
The stand-alone microphone preamp......Page 84
Physical characteristics of cables......Page 85
Ground loops......Page 86
Gain structure......Page 87
Summing multiple inputs into a single output channel......Page 89
Microphones using the rf (radio frequency) transmission principle......Page 90
Digital microphones......Page 91
References......Page 93
Preface\r......Page 94
Recording Studios......Page 0
Overview......Page 95
Input channels......Page 96
Output section......Page 98
In-line and split configurations......Page 100
Further aspects of the in-line design......Page 102
Channel grouping......Page 103
An overview of typical mixer facilities......Page 105
Routing section......Page 106
Equalizer section......Page 107
Channel and mix controls......Page 109
Master control section......Page 111
Patchbay or jackfield......Page 112
Principal EQ bands......Page 113
Input noise......Page 115
Frequency response......Page 116
Metering systems......Page 117
Problems with mechanical meters......Page 118
Electronic bargraph metering......Page 119
Meter take-off point......Page 120
Fader automation......Page 121
Storing the automation data......Page 124
Retrofitting automation......Page 125
Dynamic and static systems......Page 126
Assignable control surfaces......Page 127
Digital mixers – a case study......Page 128
Mixers with integrated control of digital workstations......Page 130
Introduction to mixing approaches......Page 132
Level setting......Page 133
Using audio groups......Page 134
Preface\r......Page 135
Calculating wire resistance......Page 136
Resistance and gage size......Page 138
Conductor parameters......Page 139
Stranded cables......Page 142
Skin effect......Page 143
Current capacity......Page 144
Wire current ratings......Page 145
Plastics and dielectric constant......Page 146
Wire insulation characteristics......Page 147
Teflon®......Page 148
Single conductor......Page 149
Pairs and balanced lines......Page 150
Analog multipair snake cable......Page 151
DVI......Page 153
IEEE – 1394 or firewire serial digital......Page 154
USB......Page 155
Premise/data category cables......Page 156
History of coaxial cable......Page 164
Coaxial cable construction......Page 165
CATV broadband cable......Page 166
Twist-on connectors......Page 167
Video triaxial cable......Page 168
RGB......Page 169
Cables and SDI......Page 170
Receiver quality......Page 171
Radio guide designations......Page 172
Velocity of propagation......Page 173
Braid......Page 174
Combination shields......Page 175
Shield current-induced noise......Page 176
Telescopic grounds......Page 177
UTP and Audio......Page 178
So why shields?......Page 179
Triboelectric noise......Page 180
Long line audio twisted pairs......Page 181
Delay and delay skew......Page 182
Characteristic impedance......Page 183
Characteristic impedance......Page 185
Twisted-pair impedance......Page 186
Loudspeaker cable......Page 187
Damping factor......Page 190
Crosstalk......Page 191
Designation and environmental areas......Page 193
Final considerations......Page 194
Plenum cable......Page 196
AC power cords and receptacles......Page 197
International power......Page 199
Bibliography......Page 205
Preface\r......Page 206
Basic electronics......Page 207
Circuit theory......Page 208
Capacitance, inductance, and impedance......Page 209
Single wires......Page 210
Cables and transmission lines......Page 211
Balanced and unbalanced interfaces......Page 212
Voltage dividers and impedance matching......Page 213
Line drivers and cable capacitance......Page 214
Capacitive coupling and shielding......Page 215
Inductive coupling and shielding......Page 216
Earth grounding......Page 218
Fault or safety grounding......Page 219
Signal grounding and EMC......Page 221
Grounding and system noise......Page 222
Parasitic transformers and inter-outlet ground voltage noise......Page 223
Interface problems in systems......Page 225
Degraded common-mode rejection......Page 226
The pin 1 problem......Page 228
Balanced cable issues......Page 231
Coupling in unbalanced cables......Page 233
Bandwidth and RF interference......Page 234
Observations, clues, and diagrams......Page 235
The ground dummy procedure......Page 236
Ground isolators......Page 238
Multiple grounding......Page 240
Unbalanced to balanced and vice versa......Page 242
RF interference......Page 243
Signal quality......Page 244
Tips for unbalanced interfaces......Page 245
Grounding from technical to bizarre......Page 246
Power-line isolation, filtering, and balancing......Page 247
Surge protection......Page 248
Exotic audio cables......Page 249
References......Page 250
Trademarks......Page 251
Preface......Page 252
The three-stage amplifier architecture......Page 253
The two-stage amplifier architecture......Page 254
The four-stage amplifier architecture......Page 255
Power amplifier classes......Page 256
Class-D......Page 257
Class-G......Page 258
Class-H......Page 259
The blomley principle......Page 260
Amplifier bridging......Page 261
Fractional bridging......Page 262
AC- and DC-coupled amplifiers......Page 263
The advantages of AC -coupling......Page 264
The advantages of DC-coupling......Page 265
Negative feedback in power amplifiers......Page 267
Some common misconceptions about negative feedback......Page 269
Amplifier stability and NFB......Page 271
Overall feedback versus local feedback......Page 277
References......Page 279
Preface......Page 281
How a Generic Amplifier Works......Page 282
The Distortion Mechanisms......Page 284
Distortion 4: VAS-Loading Distortion......Page 285
Distortion 11: Premature Overload Protection......Page 286
The Performance of a Standard Amplifier......Page 287
Direct Open-Loop Gain Measurement......Page 288
The Concept of the Blameless Amplifier......Page 290
References......Page 291
Preface\r......Page 292
The principles of class-G......Page 293
Introducing series class-G......Page 294
Efficiency of class-G......Page 295
Practicalities......Page 297
The linearity issues of series class-G......Page 298
The static linearity......Page 300
Controlling small-signal distortion......Page 302
The performance......Page 305
Adding two-pole compensation......Page 308
References......Page 311
Preface\r......Page 312
A brief look at the concept......Page 313
A little history and some background......Page 314
Some other problems......Page 315
Acoustic wave propagation......Page 316
Mechanical and acoustic impedance......Page 317
Impedance in loudspeakers......Page 318
The practical moving-coil cone loudspeaker......Page 319
The combined response......Page 320
Resistive and reactive loads......Page 321
The bigger picture......Page 326
References......Page 327
Preface\r......Page 328
Moving-coil cone loudspeakers......Page 329
Cones......Page 331
Surrounds......Page 334
Rear suspensions......Page 335
The chassis......Page 337
Magnet systems......Page 338
The complete system......Page 340
Hard and soft domes......Page 341
Compression drivers......Page 344
Ribbon loudspeakers......Page 346
Heil air-motion transformers......Page 347
Distributed-mode loudspeakers......Page 349
Panel/piston combinations......Page 352
Electrostatic loudspeakers......Page 353
Electromagnetic planar loudspeakers......Page 357
References......Page 358
Preface\r......Page 359
The concept of the infinite baffle......Page 360
The sealed box......Page 361
Reflex enclosures......Page 363
Acoustic labyrinths......Page 365
Modern transmission lines......Page 368
ABR systems......Page 370
Bandpass cabinets......Page 371
Series driver operation and isobaric loudspeakers......Page 372
Cabinet lining materials......Page 373
Cabinet shapes and diffraction effects......Page 374
Cabinet mounting......Page 377
References......Page 379
Preface\r......Page 380
What is a crossover?......Page 381
Reconstruction problems......Page 383
Orders, slopes and shapes......Page 386
Filter shapes......Page 390
Minimum and non-minimum phase effects......Page 393
Active versus passive crossovers......Page 394
Physical derivation of crossover delay......Page 398
Digital crossovers......Page 399
References......Page 401
Preface\r......Page 402
Digital signal processing......Page 403
Sequences......Page 404
Systems......Page 405
Linearity......Page 407
Linear time-invariant systems......Page 408
Frequency domain representation......Page 409
The Z-Transform......Page 411
Continuous to discrete conversion......Page 413
Sampling theory......Page 415
Quantization......Page 416
Algorithm development......Page 418
Digital signal processors......Page 419
DSP Arithmetic......Page 420
System delay......Page 421
Choosing a DSP......Page 422
Conclusion......Page 424
References......Page 425
Preface\r......Page 426
What MIDI isn’t......Page 427
The MIDI message......Page 428
MIDI channels......Page 429
MIDI modes......Page 430
Channel messages......Page 431
System messages......Page 435
Hardware systems within MIDI production......Page 440
The MIDI interface......Page 443
Hardware and software electronic instruments......Page 444
Performance and parameter controllers......Page 448
Sequencers......Page 450
A basic introduction to sequencers......Page 451
Other software sequencing applications......Page 453
Multimedia and the web......Page 458
MIDI-based synchronization......Page 459
MIDI real-time messages......Page 460
Song position pointer......Page 462
MIDI time code......Page 463
Preface\r......Page 465
What is a large room?......Page 466
Use of the Sabinian equations in large reverberant spaces......Page 467
The Sabine equation......Page 469
Specific versus statistical......Page 470
Improved reverberation time calculations......Page 471
Sound power level, LW......Page 472
Sound pressure level, LP......Page 473
Hopkins-Stryker—U.S. and SI......Page 475
Other terms derived from Hopkins-Stryker......Page 477
Differentiating between reverberant level and reverberation time......Page 479
Analyzing reflections and their paths......Page 480
Sound system near regeneration......Page 481
Variations in the measurement of reverberation......Page 482
Q versus Sā for controlling Dc......Page 483
Theory of Ma......Page 484
The effect of the N factor......Page 485
Bibliography......Page 487
Preface\r......Page 489
Early research on equalization......Page 490
Feedback defined......Page 491
Growth......Page 492
Decay......Page 493
Introduction of real-time analyzers......Page 495
Forty years later......Page 496
Band-rejection, bandpass, and band-boost filters......Page 497
Filter parameters......Page 499
Characteristics of successful filters......Page 500
Filter transfer characteristics......Page 503
Minimum-phase filters......Page 504
TEF analysis in equalization......Page 507
How to approach equalization......Page 508
Feedback is a single frequency......Page 509
What can an equalizer equalize?......Page 510
Mother nature’s way......Page 511
Degree of correction necessary......Page 512
Equalizing for playback......Page 513
House curves......Page 514
Checking Microphone Polarity......Page 515
Bibliography......Page 516
Preface\r......Page 517
Audible effects of a si ngle reflection......Page 518
Effects of a single reflection......Page 521
Reflections from different directions......Page 523
The IEC Room......Page 525
Real versus simulated rooms......Page 526
Experimental results with music and other sounds......Page 527
Threshold curve shapes for different sounds......Page 528
Single versus multiple reflections......Page 530
Measuring reflections......Page 531
References......Page 533
Preface\r......Page 535
Vibrational behavior......Page 536
Relevance to isolation......Page 537
Floating structures......Page 538
Floating system choices......Page 539
Practical floors......Page 542
Floors on weak sub-floors......Page 547
Ceiling isolation......Page 548
A trip through the ceiling......Page 550
Summing the results......Page 553
Wall isolation......Page 554
Reciprocity and impact noises......Page 555
The distance option......Page 558
Fibrous and cellular springs-thicknesses and densities......Page 559
The general situation with masses and springs......Page 560
Measured characteristics of various suspension materials......Page 565
Calculation of resonance frequency......Page 567
Summary......Page 568
Reference......Page 570
Preface\r......Page 571
Artificial light......Page 572
Ventilation and air-conditioning......Page 573
Ventilation......Page 574
Air-conditioning systems and general mechanical noises......Page 576
Headphone foldback......Page 579
Loudspeaker foldback......Page 580
AC mains supplies......Page 581
Phase......Page 582
Balanced power......Page 583
Earthing......Page 584
Reference......Page 585
B......Page 586
C......Page 587
E......Page 588
H......Page 589
L......Page 590
M......Page 591
P......Page 592
R......Page 593
S......Page 594
T......Page 595
Z......Page 596