Digital Audio Signal Processing

The fully revised new edition of the popular textbook, featuring additional MATLAB exercises and new algorithms for processing digital audio signals

Digital Audio Signal Processing (DASP) techniques are used in a variety of applications, ranging from audio streaming and computer-generated music to real-time signal processing and virtual sound processing.

Digital Audio Signal Processing provides clear and accessible coverage of the fundamental principles and practical applications of digital audio processing and coding. Throughout the book, the authors explain a wide range of basic audio processing techniques and highlight new directions for automatic tuning of different algorithms and discuss state- of-the-art DASP approaches. Now in its third edition, this popular guide is fully updated with the latest signal processing algorithms for audio processing. Entirely new chapters cover nonlinear processing, Machine Learning (ML) for audio applications, distortion, soft/hard clipping, overdrive, equalizers and delay effects, sampling and reconstruction, and more.

• Covers the fundamentals of quantization, filters, dynamic range control, room simulation, sampling rate conversion, and audio coding
• Describes DASP techniques, their theoretical foundations, and their practical applications
• Discusses modern studio technology, digital transmission systems, storage media, and home entertainment audio components
• Features a new introductory chapter and extensively revised content throughout
• Provides updated application examples and computer-based activities supported with MATLAB exercises and interactive JavaScript applets via an author-hosted companion website

Balancing essential concepts and technological topics, Digital Audio Signal Processing, Third Edition remains the ideal textbook for advanced music technology and engineering students in audio signal processing courses. It is also an invaluable reference for audio engineers, hardware and software developers, and researchers in both academia and industry.

Udo Zölzer is Professor of Signal Processing and Communication at Helmut Schmidt University, Hamburg, Germany. His research interests include audio and video signal processing and communications. He is the author of several books including DAFX: Digital Audio Effects.

Preface v

1 Introduction 1
U. Z¨olzer

1.1 Continuous-time Signals and Convolution 1

1.2 Continuous-time Fourier Transform and Laplace Transform 6

1.3 Sampling and Reconstruction 7

1.4 Discrete-time Signals and Convolution 8

1.5 Discrete-time Fourier Transform and Z-Transform 11

1.6 Discrete Fourier Transform 12

1.7 FIR and IIR Filters 12

1.8 Adaptive Filters 19

1.9 Exercises 22

References 24

2 Quantization 25
U. Z¨olzer

2.1 Signal Quantization 25

2.1.1 Classical Quantization Model 25

2.1.2 Quantization Theorem 29

2.1.3 Statistics of Quantization Error 34

2.2 Dither 41

2.2.1 Basics 41

2.2.2 Implementation 44

2.2.3 Examples 45

2.3 Spectrum Shaping of Quantization - Noise Shaping 48

2.4 Number Representation 53

2.4.1 Fixed-point Number Representation 54

2.4.2 Floating-point Number Representation 58

2.4.3 Effects on Format Conversion and Algorithms 62

2.5 JS Applet - Quantization, Dither, and Noise Shaping 64

2.6 Exercises 65

References 67

3 Sampling Rate Conversion 69
U. Z¨olzer

3.1 Basics 69

3.1.1 Upsampling and Anti-Imaging Filtering 70

3.1.2 Downsampling and Anti-Aliasing Filtering 71

3.2 Synchronous Conversion 72

3.3 Asynchronous Conversion 75

3.3.1 Single-stage Methods 78

3.3.2 Multistage Methods 80

3.3.3 Control of Interpolation Filters 83

3.4 Interpolation Methods 85

3.4.1 Polynomial Interpolation 85

3.4.2 Lagrange Interpolation 88

3.4.3 Spline Interpolation 89

3.5 Exercises 97

References 98

4 AD/DA Conversion 101
U. Z¨olzer

4.1 Methods 101

4.1.1 Nyquist Sampling 101

4.1.2 Oversampling 103

4.1.3 Delta-sigma Modulation 104

4.2 AD Converters 117

4.2.1 Specifications 117

4.2.2 Parallel Converter 120

4.2.3 Successive Approximation 121

4.2.4 Counter Methods 123

4.2.5 Delta-sigma AD Converter 124

4.3 DA Converters 125

4.3.1 Specifications 125

4.3.2 Switched Voltage and Current Sources 127

4.3.3 Weighted Resistors and Capacitors 128

4.3.4 R-2R Resistor Networks 129

4.3.5 Delta-sigma DA Converter 130

4.4 JS Applet - Oversampling and Quantization 131

4.5 Exercises 132

References 133

5 Audio Processing Systems 135
U. Z¨olzer, D. Ahlers

5.1 Digital Signal Processors 136

5.1.1 Fixed-point DSPs 136

5.1.2 Floating-point DSPs 137

5.2 Digital Audio Interfaces 138

5.2.1 Two-channel AES/EBU Interface 138

5.2.2 MADI Interface 142

5.2.3 Audio in HDMI 143

5.2.4 Audio Computer Interfaces 145

5.2.5 Audio Network Interfaces 145

5.3 Two-channel Systems 150

5.4 Multi-channel Systems 152

References 152

6 Equalizers 153
U. Z¨olzer

6.1 Basics 153

6.2 Recursive Audio Filters 157

6.2.1 Design 157

6.2.2 Parametric Filter Structures 168

6.2.3 Quantization Effects 175

6.3 Nonrecursive Audio Filters 196

6.3.1 Basics of Fast Convolution 196

6.3.2 Fast Convolution of Long Sequences 200

6.3.3 Filter Design by Frequency Sampling 207

6.4 Multi-complementary Filter Bank 208

6.4.1 Principles 209

6.4.2 Example: 8-Band Multi-complementary Filter Bank 214

6.5 Delay-based Audio Effects 220

6.6 JS Applet - Audio Filters 221

6.7 Exercises 223

References 227

7 Room Simulation 233
U. Z¨olzer, P. Nowak, P. Bhattacharya

7.1 Basics 233

7.1.1 Room Acoustics 233

7.1.2 Model-based Room Impulse Responses 234

7.1.3 Measurement of Room Impulse Responses 237

7.1.4 Simulation of Room Impulse Responses 242

7.2 Early Reflections 243

7.2.1 Ando’s Investigations 244

7.2.2 Gerzon Algorithm 244

7.3 Subsequent Reverberation 249

7.3.1 Schroeder Algorithm 249

7.3.2 General Feedback Systems 257

7.3.3 Feedback All-pass Systems 261

7.4 Approximation of Room Impulse Responses 265

7.5 JS Applet - Fast Convolution 268

7.6 Exercises 269

References 270

8 Dynamic Range Control 275
U. Z¨olzer, E. Gerat

8.1 Basics 275

8.2 Static Curve 276

8.3 Dynamic Behavior 279

8.3.1 Level Measurement 279

8.3.2 Gain Factor Smoothing 282

8.3.3 Time Constants 282

8.4 Implementation 283

8.4.1 Limiter 284

8.4.2 Compressor 284

8.4.3 Compressor, Expander, Noise Gate 286

8.4.4 Combination System 286

8.5 Realization Aspects 289

8.5.1 Sampling Rate Reduction 289

8.5.2 Curve Approximation 290

8.5.3 Stereo Processing 290

8.6 Multi-band DRC 291

8.7 Dynamic Equalizers 291

8.8 Source-Filter DRC 293

8.8.1 Introduction 293

8.8.2 Combination with DRC 295

8.8.3 Applications 295

8.9 JS Applet - Dynamic Range Control 298

8.10 Exercises 299

References 300

9 Audio Coding 303
U. Z¨olzer, P. Bhattacharya

9.1 Lossless Audio Coding 303

9.2 Lossy Audio Coding 305

9.3 Psychoacoustics 307

9.3.1 Critical Bands and Absolute Threshold 308

9.3.2 Masking 309

9.4 ISO-MPEG1 Audio Coding 314

9.4.1 Filter Banks 315

9.4.2 Psychoacoustic Models 318

9.4.3 Dynamic Bit Allocation and Coding 321

9.5 MPEG-2 Audio Coding 322

9.6 MPEG-2 Advanced Audio Coding 322

9.7 MPEG-4 Audio Coding 334

9.8 Spectral Band Replication 336

9.9 Constrained Energy Lapped Transform - Gain and Shape Coding 339

9.9.1 Gain Quantization 341

9.9.2 Shape Quantization 344

9.9.3 Range Coding 345

9.9.4 CELT Decoding 345

9.10 JS Applet - Psychoacoustics 346

9.11 Exercises 347

References 348

10 Nonlinear Processing 355
M. Holters, L. K¨oper

10.1 Fundamentals 355

10.2 Overdrive, Distortion, Clipping 357

10.3 Nonlinear Filters 361

10.4 Aliasing and its Mitigation 365

10.5 Virtual Analog Modeling 370

10.5.1 Wave Digital Filters 370

10.5.2 State-Space Approaches 376

10.6 Exercises 379

References 380

11 Machine Learning for Audio 383
P. Bhattacharya, P. Nowak, U. Z¨olzer

11.1 Introduction 383

11.2 Unsupervised and Supervised Learning 384

11.3 Gradient Descent and Backpropagation 386

11.3.1 Feedforward Artificial Neural Network 386

11.3.2 Convolutional Neural Network 390

11.4 Applications 392

11.4.1 Parametric Filter Adaptation 392

11.4.2 Room Simulation 401

11.4.3 Audio Denoising 406

11.5 Exercises 412

References 413

Index 419

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.