High Definition Audio for the Digital Home

Proven Techniques For Getting It Right The First Time

by David Roach, Scott Janus, and Wayne Jones

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Table of Contents


 
 

Foreword   XV

  • High-Fidelity Audio Everywhere XV
  • High-Fidelity Audio for Everyone XVI

Preface   XIX

  • Market Challenges and Motivations XX
  • Acknowledgements XXI
  • High Definition Audio System Diagram – Companion to this book XXIV

Chapter 1   Audio Basics   1

  • The Audio History of Entertainment 2
  • Early Phonograph Players 2
  • Radio 3
  • Record Players 3
  • Home Appliances and the Radio, Stereo System 3
  • Home Theater 4
  • Portable and “Personal” Stereo Devices (MP3 Players) 4
  • PC Music “Jukeboxes”  and Digital Home Media Centers 5
  • Human Auditory Perception and Acoustics 6
  • Frequency Range of Human Hearing 6
  • Frequency or Pitch Scale 7
  • The Harmonic Series 8
  • Amplitude Units (dB) 9
  • Absolute dB units 10
  • Acoustic Levels (dBSPL) 10
  • Dynamic Range 11
  • Sound Levels 12
  • Frequency Response vs. Audible Level 14
  • Masking 15
  • Analog Audio 16
  • Critical Measurement Parameters 17
  • Establishing Reference Levels 17
  • Frequency Response 18
  • Noise 21
  • Nonlinear Distortion 30
  • Crosstalk 35
  • Interchannel Phase Difference 37
  • Digital Audio 39
  • Digital Audio Sampling Theory 39
  • Oversampling 44
  • Quantizing 45
  • Quantization Error and Dithering 47
  • Noise Shaping 48
  • Resolution or Bit Depth 48
  • Reconstructing Analog From Digital 48
  • Other Errors 48
  • Putting It All Together 49
  • Advantages of Digital Audio 50

Chapter 2   Audio Interfaces   51

  • Analog Interfaces 51
  • Analog Connectors 52
  • PC Color Coding 63
  • Jack-Presence Detection 67
  • Circuit Topologies 68
  • Signal Levels and Impedances 77
  • Digital Interfaces 78
  • S/PDIF Inputs and Outputs 78
  • Encoding 84
  • Other Digital Audio Formats 86
  • ADAT Optical 87
  • I2S 88
  • DSD 89
  • MIDI 91
  • FireWire/IEEE-1394 91
  • USB 94
  • HDMI 97
  • 1394 versus USB versus HDMI 103

Chapter 3   Basics of Surround Sound and Signal Processing   105

  • Surround Sound and Multiple Channels 105
  • Historical Background 106
  • Fitting 6, 7, or 8 Channels into 2 107
  • Channels and Bass Management 108
  • Spatial Perception 109
  • Speaker Placement in the Listening Environment 110
  • Surround Sound Formats 110
  • Equalization 114
  • Cut/Boost Bandpass EQ 115
  • Graphic EQ 116
  • Parametric EQ 116
  • Equalizer Implementations 118
  • Bass Management 119
  • Dynamics Processing 120
  • Compression 121
  • Limiting 122
  • Expansion 123
  • Noise Gate 123
  • Multi-band Compression and Limiting 124
  • 3D Virtualization 125
  • 2-to-N Spreaders 126
  • Encoders and Decoders for Compressed Audio 126
  • Uncompressed Audio 127
  • Lossless Compression 127
  • Lossy Compression 128
  • Economics of Lossy Compression 129
  • Input and Capture 131
  • Speech Usage Scenarios 132
  • Beamforming Array Microphones 133
  • Acoustic Echo Cancellation (AEC) 133
  • Noise Suppression 134
  • VoIP Application 134
  • Commercially Available Signal Processing for PCs 135
  • Dolby† Processing Algorithms 136
  • Dolby† PC Entertainment Experience (PCEE) 137
  • DTS 139
  • SRS 139
  • Sonic Focus 139
  • MaxxBass by Waves 140
  • Intellisonics by Knowles Acoustics 141
  • Professional Audio Applications 142

Chapter 4   Introduction to Intel® High Definition Audio   143

  • Hardware 144
  • Controller 145
  • Link 146
  • Topology 147
  • Data and Timings 149
  • Codec 150
  • Introducing…the Widget 151
  • Widgets in Practice 155
  • Command and Data Flow 156
  • Verbs 156
  • Responses 158
  • Hardware Volume Scaling 159
  • Pin Widget Control 163
  • Standard Packaging 164
  • Pins, Pin Widgets, and Ports 165
  • Verb Tables 168
  • Sending Verb Tables to the Codec 170
  • Muting and Startup Work-arounds 171
  • Pin Configuration Registers 174
  • Associations and Sequences 180
  • Resource Sharing 186
  • Resource Allocation 192
  • Unsolicited Response 192
  • Jack Detection 193
  • Modifying the Pin Configuration in the BIOS 194
  • System Bring-up Trick Using the Microsoft UAA class driver for Intel HD Audio 194

Chapter 5   Motherboard Layout Guidelines for Increased Audio Fidelity   197

  • The Art of Audio Design 197
  • Multiple Complaints about Audio in today’s PCs 199
  • Everything Affects Audio 200
  • Motherboard Development Cycles 200
  • Schematic Design 201
  • Gerber Plots 201
  • Hardware Prototypes 202
  • System Test 202
  • Commonly Encountered Problems 202
  • Electrical Noise Sources 203
  • Passive Components 203
  • Capacitors 204
  • Capacitor Tolerance and Variation 207
  • Power Supplies 207
  • Isolation 209
  • One Port, One Jack 210
  • Ground Planes and Shielding 210
  • Star Grounding 211
  • Laptops and All-in-One Systems 212
  • Speech and Real Time Communications 213
  • Front Panel Considerations 213
  • Analog Microphones 214
  • Challenges in mic Array Implementation 215
  • The Benefits of a Digital Microphone Array 216
  • Electromagnetic Interference  and Electrostatic Discharge 219
  • EMI 219
  • ISOLATE 223
  • BITCLK 224
  • EMI and ESD Suppression Circuits 224
  • ESD 226
  • Troubleshooting and Debugging 231
  • Test Equipment 232
  • Troubleshooting: Power Supply 232
  • Troubleshooting: Signal Tracing 233
  • Troubleshooting Pops and Clicks 233
  • Troubleshooting SNR and THD+N 234
  • Troubleshooting Frequency Response 235
  • Troubleshooting Active Outputs 235
  • “Golden” Passive Components 235

Chapter 6   Recommendations for Media PCs   237

  • Audio Attributes of a Media PC 237
  • Pops and Clicks 239
  • System Start-up (Cold Boot) 242
  • System Shutdown (Power off) 243
  • Suspend 245
  • Resume 245
  • Software-induced Pops and Clicks 245
  • DC Offsets 247
  • Zipper Noise 248
  • External Pop Suppression Circuits 248
  • Series Pop Suppression Circuits 248
  • Shunt Pop Suppression Circuits 250
  • Pop Suppression for Built-in Headphone and Speaker Amplifiers 253
  • Interfacing to Consumer Electronics Equipment 254
  • Interfacing to 2V RMS Input Signals from Consumer Devices 254
  • Interfacing 2V RMS Line Output to Consumer Devices 256
  • Guidelines for RCA Jacks for Analog Line Level I/O 258

Chapter 7   Intel® HD Audio Software: Control Layer   263

  • Sounds and Audio Devices Properties 263
  • CD Audio: Analog or Digital? 266
  • Sticky Keys, Toggle Keys, and the 8253 Timer 268
  • WAVE_FORMAT_EXTENSIBLE 271
  • Multi-channel Speaker Configurations 273
  • Bit Depths and Sample Rates for Windows XP 279
  • Plug and Play 280
  • INF Files 283
  • UAA Class Drivers 284
  • UAA Intel HD Audio Bus Driver 285
  • Drivers for X64 Versions 285
  • Installing an Audio Driver 286
  • Applications Installers 287
  • Linux and Intel HD Audio 287
  • Working with Audio Devices in Linux 288
  • Linux Applications for High Definition Audio 289

Chapter 8   Intel HD Audio Software: Signal Processing and Volume Control   291

  • Modes of Operation 292
  • The Differences Between ISR, DPC, and SMI 293
  • Windows XP Audio Stack 295
  • SNDVOL32: The Misunderstood Windows Mixer 296
  • MIXERLINE and SNDVOL32 302
  • Master Volume in Windows XP 302
  • Direct Mode and Hardware Volume Events 304
  • Indirect Mode and Software Volume Events 306
  • Linear and Log Volume Scales 309
  • Volume Tables for Audio Taper 311
  • Volume Remapping 314
  • Master Volume: Analog vs. Digital 315
  • Signal Processing in Windows XP 315
  • Signal Processing in DirectShow 315
  • Signal Processing in an Upper Filter Driver 317
  • Signal Processing in the Miniport Driver 317
  • Windows Vista 318
  • What Won’t Change In Vista Audio? 319
  • WaveRT 319
  • User Mode Audio (UMA) 321
  • Per-application Volume Control 322
  • Audio Processing in the Global Audio Engine 323
  • Preparing Audio Subsystems for Windows Vista 324

Chapter 9   The Intel HD Audio System as a Whole   329

  • Multiple Layers 330
  • The Real World Layer 330
  • The Motherboard or System Layer 331
  • The Intel HD Audio Codec Layer 333
  • The Intel HD Audio Bus, Controller, and Bus Driver 334
  • The Kernel-Mode Software Layer in Windows XP 334
  • The User-Mode Software Layer in Windows XP 337
  • The User Mode Audio Engine Layer in Windows Vista 337
  • The Application Layer in Windows Vista 339
  • Putting It All Together 339

Chapter 10   Security and Content Protection   341

  • Important Disclaimer 342
  • Content Protection Basics 343
  • Compliance and Robustness 343
  • Open versus Closed Systems 344
  • User Accessible Buses 345
  • Types of Content 346
  • Cryptography Basics 346
  • Secret Key Encryption 346
  • Public Key Encryption 347
  • Contemporary Systems 349
  • SCMS 349
  • HDCP 350
  • HDMI 353
  • Windows Media Digital Rights Management 353
  • Content Scramble System (CSS) 356
  • Content Protection for Pre-recorded Media (CPPM) 356
  • Digital Transmission Content Protection (DTCP) 357
  • Advanced Access Content System (AACS) 358
  • Content Protection on the PC 359
  • SAP 359
  • PMP 362
  • Protected Environment 363
  • Media Interoperability Gateway 365
  • Protected User Mode Audio 367
  • PAP 368

Chapter 11   Testing and Certification   371

  • The Ever-growing Unwieldy Test Matrix 371
  • Per-Unit Testing 372
  • Audio Codec Manufacturing Verification Testing 372
  • Motherboard Manufacturing Verification Testing 373
  • System Level Verification Testing 373
  • System Design Validation Testing 374
  • Usability Testing 374
  • Acoustic Fidelity Testing 375
  • Acoustic Noise Emission Testing 375
  • Functional Software Testing 375
  • Automated Software Testing 376
  • Windows Driver Kit (WDK) 376
  • Audio Fidelity Testing 377
  • Test Setup 377
  • Testing Technologies 383
  • Acoustic Measurements 386
  • Acoustic Noise Emission testing 388
  • Audible Mechanical Defects (Rub & Buzz) 389
  • Testing Intel HD Audio Systems 390
  • Interfacing to the System Under Test 391
  • Digital Interface 395
  • Interfacing to the Digital Domain 395
  • Separating the Paths 399
  • Establishing Reference Levels 400
  • Detailed Test Procedure Descriptions 401
  • Digital to Analog (Playback) Paths 410
  • Additional Tests 418

Appendix A   Pin Configuration  Verb Tables   425

  • Subsystem ID 426
  • Front Panel Headphone Output 427
  • Rear Panel Line Input 428
  • Rear Panel Line Output 429
  • Front Panel Microphone Input 430
  • Rear Panel S/PDIF Output 431
  • Rear Panel 5.1 Surround Line Outputs 432
  • Rear Panel 7.1 Surround Line Outputs 435
  • Rear Panel Line Out w/ Redirected Front Panel HP Out 438
  • Internal Speaker w/ Redirected Front Panel HP Out 440
  • Internal Speaker w/ Redirected Rear Panel Line Out 442
  • Shared Input Mux with Line In, CD In, and Microphone In 444
  • Shared Input Mix with Line In, CD In, and Microphone In 446
  • Rear Panel 5.1 Surround Line Outputs with  Redirected Front Panel Headphone Output 448
  • Set All DACs to Mute 451
  • Set All Pin Widgets to Disabled State 452

Appendix B   PC Audio Hardware History:  Then and Now   453

  • The ISA Era 454
  • The PCI Era 454
  • The Chipset Era 455
  • AC97 457
  • CNR 458
  • AC97 in Practice 460
  • High Definition Audio 460

Appendix C   Audio Drivers from DOS to Windows† XP   461

  • Windows 3.0 and Multi-Media Extensions 461
  • Windows† 3.1 462
  • Windows NT 462
  • DirectSound 463
  • Windows 95 464
  • Windows 98 and WDM Drivers 464
  • Windows 2000 465
  • Windows Millennium Edition (ME) 465
  • Windows XP 465
  • Universal Audio Architecture 466

Appendix D   Jack Retasking   467

  • Jack Detection 468
  • Switchable Microphone Bias 468
  • Redirection 470
  • Impedance Sensing 471
  • Analog Device Classification 471
  • Usability 472
  • UAA Class Driver Support 472
  • Types of Retasking Circuits 472
  • Line Out and Headphone Out (LO/HP) 473
  • Line In, Line Out, and HP Out (LI/LO/HP) 474
  • Line In and Line Out (LI/LO) 475
  • Microphone In and Line In (MI/LI) 476
  • Microphone In, Line In, and Line Out (MI/LI/LO) 478
  • Mic In, Line In, Line Out, & HP Out (MI/LI/LO/HP) 479
  • Recommendations for Retasking 481

Glossary   483


References   513


Index   517