About the Authors xix

Preface xxi

Preface to the Unfinished Manuscript of the Book xxiii

Introduction 1

1 How to Study and Develop Communication Acoustics 7

1.1 Domains of Knowledge 7

1.2 Methodology of Research and Development 8

1.3 Systems Approach to Modelling 10

1.4 About the Rest of this Book 12

1.5 Focus of the Book 12

1.6 Intended Audience 13

References 14

2 Physics of Sound 15

2.1 Vibration and Wave Behaviour of Sound 15

2.2 Acoustic Measures and Quantities 23

2.3 Wave Phenomena 26

2.4 Sound in Closed Spaces: Acoustics of Rooms and Halls 34

Summary 41

Further Reading 41

References 41

3 Signal Processing and Signals 43

3.1 Signals 43

3.2 Fundamental Concepts of Signal Processing 46

3.3 Digital Signal Processing (DSP) 56

3.4 Hidden Markov Models 62

3.5 Concepts of Intelligent and Learning Systems 63

Summary 64

Further Reading 64

References 64

4 Electroacoustics and Responses of Audio Systems 67

4.1 Electroacoustics 67

4.2 Audio System Responses 71

4.3 Response Equalization 76

Summary 77

Further Reading 78

References 78

5 Human Voice 79

5.1 Speech Production 79

5.2 Units and Notation of Speech used in Phonetics 84

5.3 Modelling of Speech Production 90

5.4 Singing Voice 96

Summary 96

Further Reading 97

References 97

6 Musical Instruments and Sound Synthesis 99

6.1 Acoustic Instruments 99

6.2 Sound Synthesis in Music 104

Summary 108

Further Reading 108

References 108

7 Physiology and Anatomy of Hearing 111

7.1 Global Structure of the Ear 111

7.2 External Ear 112

7.3 Middle Ear 113

7.4 Inner Ear 115

7.5 Otoacoustic Emissions 123

7.6 Auditory Nerve 123

7.7 Auditory Nervous System 127

7.8 Motivation for Building Computational Models of Hearing 130

Summary 131

Further Reading 131

References 131

8 The Approach and Methodology of Psychoacoustics 133

8.1 Sound Events versus Auditory Events 133

8.2 Psychophysical Functions 135

8.3 Generation of Sound Events 135

8.4 Selection of Subjects for Listening Tests 138

8.5 What are We Measuring? 138

8.6 Tasks for Subjects 141

8.7 Basic Psychoacoustic Test Methods 142

8.8 Descriptive Sensory Analysis 145

8.9 Psychoacoustic Tests from the Point of View of Statistics 149

Summary 149

Further Reading 150

References 150

9 Basic Function of Hearing 153

9.1 Effective Hearing Area 153

9.2 Spectral Masking 156

9.3 Temporal Masking 161

9.4 Frequency Selectivity of Hearing 163

Summary 169

Further Reading 169

References 169

10 Basic Psychoacoustic Quantities 171

10.1 Pitch 171

10.2 Loudness 179

10.3 Timbre 188

10.4 Subjective Duration of Sound 189

Summary 191

Further Reading 191

References 191

11 Further Analysis in Hearing 193

11.1 Sharpness 193

11.2 Detection of Modulation and Sound Onset 195

11.3 Roughness 198

11.4 Tonality 200

11.5 Discrimination of Changes in Signal Magnitude and Phase Spectra 201

11.6 Psychoacoustic Concepts and Music 206

11.7 Perceptual Organization of Sound 212

Summary 216

Further Reading 217

References 217

12 Spatial Hearing 219

12.1 Concepts and Definitions for Spatial Hearing 219

12.2 Head-Related Acoustics 222

12.3 Localization Cues 226

12.4 Localization Accuracy 235

12.5 Directional Hearing in Enclosed Spaces 239

12.6 Binaural Advantages in Timbre Perception 241

12.7 Perception of Source Distance 243

Summary 246

Further Reading 246

References 246

13 Auditory Modelling 249

13.1 Simple Psychoacoustic Modelling with DFT 250

13.2 Filter Bank Models 255

13.3 Cochlear Models 260

13.4 Modelling of Higher-Level Systemic Properties 263

13.5 Models of Spatial Hearing 265

13.6 Matlab Examples 270

Analysis 272

Summary 274

Further Reading 274

References 274

14 Sound Reproduction 277

14.1 Need for Sound Reproduction 277

14.2 Audio Content Production 279

14.3 Listening Set-ups 280

14.4 Recording Techniques 284

14.5 Virtual Source Positioning 293

14.6 Binaural Techniques 298

14.7 Digital Audio Effects 302

14.8 Reverberators 303

Summary 306

Further Reading and Available Toolboxes 306

References 307

15 Time-Frequency-domain Processing and Coding of Audio 311

15.1 Basic Techniques and Concepts for Time-Frequency Processing 311

15.2 Time-Frequency Transforms 317

15.3 Time-Frequency-Domain Audio-Processing Techniques 328

Summary 332

Further Reading 332

References 332

16 Speech Technologies 335

16.1 Speech Coding 336

16.2 Text-to-Speech Synthesis 338

16.3 Speech Recognition 345

Summary 346

Further Reading 347

References 347

17 Sound Quality 349

17.1 Historical Background of Sound Quality 350

17.2 The Many Facets of Sound Quality 351

17.3 Systemic Framework for Sound Quality 352

17.4 Subjective Sound Quality Measurement 353

17.5 Audio Quality 356

17.6 Quality of Speech Communication 360

17.7 Measuring Speech Understandability with the Modulation Transfer Function 363

17.8 Objective Speech Quality Measurement for Telecommunication 370

17.9 Sound Quality in Auditoria and Concert Halls 374

17.10 Noise Quality 377

17.11 Product Sound Quality 378

Summary 380

Further Reading 380

References 380

18 Other Audio Applications 383

18.1 Virtual Reality and Game Audio Engines 383

18.2 Sonic Interaction Design 386

18.3 Computational Auditory Scene Analysis, CASA 387

18.4 Music Information Retrieval 387

18.5 Miscellaneous Applications 389

Summary 390

Further Reading 390

References 390

19 Technical Audiology 393

19.1 Hearing Impairments and Disabilities 393

19.2 Symptoms and Consequences of Hearing Impairments 396

19.3 The Effect of Noise on Hearing 401

19.4 Audiometry 405

19.5 Hearing Aids 409

19.6 Implantable Hearing Solutions 414

Summary 416

Further Reading 417

References 417

Index 419