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Contents
Introduction xiii
Forward xv
Early Stereophonics 1.1
The First Stereo 1.3
Stereo in the 1930s 1.4
Blumlein’s Contributions 1.5
Fletcher’s Work at Bell Laboratories 1.5
How Stereo Information Is Conveyed 2.1
The Monophonic System 2.4
The Stereophonic System 2.5
Intensity Effects in Stereo 2.8
Time Effects in Stereo 2.12
Interaural Coherence 2.15
Spaciousness 2.16
Stereo and the Auditory System 3.1
Subjective/Objective Distinctions 3.1
Structure of the Ear 3.2
The Pinna 3.4
The Auditory Canal 3.4
The Middle Ear 3.5
The Inner Ear 3.5
Masking and the Auditory Filters 3.6
Binaural Unmasking 3.7
Perceptual Space 3.9
Binaural Unmasking vs. Frequency 3.1
Understanding Speech in High Background Noise 3.11
Transfer Functions 3.12
Effects of Reflected Sound 3.13
The Law of the First Wavefront 3.15
Echoes 3.16
Effect of Reflections on Music and Speech 3.16
Localization of Sound in the Median Plane 3.17
Philosophical and Pragmatic Approaches to Stereo 4.1
Fundamental Decisions 4.1
The Five W’s 4.1
Recreating an Event 4.2
Creating a New Event 4.2
The Listener’s Perspective 4.3
The “Two by Two” Matrix 4.3
Technical Considerations 4.4
Amplitude 4.4
Dynamics 4.5
Phase 4.5
Spectrum 4.5
Distortion 4.5
Recording Formats 4.6
Sonic and Visual Images 4.7
The “Law of Compromises” 4.7
Two-Microphone Stereo Techniques 5.1
Inverse Square Law 5.1
The Monophonic Sound System 5.2
The Conventional Stereo System 5.3
The “Phantom Center” Image 5.4
Phantom Stereo Imaging 5.6
The “Hole in the Middle” Effect 5.7
Reverberation 5.8
Critical Distance 5.9
Reverberation in Mono vs. Stereo 5.9
Basic Stereo Perspectives vs. Multiple-Microphone Systems 5.1
“Super Stereo” 5.1
Binaural Recording and Reproduction 6.1
Requirements of the Dummy Head 6.4
Dummy Head Recording 6.4
Binaural Reproduction by Headphones 6.5
Binaural Reproduction via Loudspeakers 6.6
Avoiding Crosstalk with Headphones 6.7
Avoiding Crosstalk with a Barrier 6.8
Cancellation of Crosstalk Electronically 6.8
The Promise of Super-Stereo Electronics 6.9
Dummy Head Developments 6.11
Informal Approaches to Dummy Heads 6.11
The Neumann Head 6.12
The Kemar Manikin 6.12
The Aachen Head 6.13
The B&K Head and Torso Simulator 6.14
A Ghostly Dummy Head 6.15
Quasi-Binaural Devices 6.15
Binaural Sound Processing 6.16
Marketing of Binaural Audio 6.16
Coincident-Microphone Stereo Techniques 7.1
Introduction 7.1
Intensity Stereo 7.1
Monophonic Compatibility 7.2
The “Blumlein” Technique 7.2
Bidirectional Microphones 7.3
Absolute Polarity 7.4
Blumlein Stereo 7.5
Other Polar Patterns 7.9
XY Stereo Techniques 7.12
Matching the Microphones 7.13
The Mid/Side Technique 7.14
Advantages of the M/S Technique 7.17
Criticisms of Coincident Stereophony 7.22
Subjective Evaluation 7.23
Audibility of Reflections 8.1
Effects of Reflected Sound 8.1
Threshold Perceptions 8.2
Audibility of Reflections of Different Signals 8.3
Audibility and Reflection Angle 8.4
Audibility and Reflection Spectrum 8.5
Audible Effects of Reflected Sounds 8.5
What Is a Comb Filter? 8.6
Tonal Signals and Comb Filters 8.7
Combing of Music and Speech Signals 8.8
Combing of Direct and Reflected Sound 8.9
Comb Filters and Critical Bands 8.12
Coloration and Spaciousness 8.14
Combing in Stereo Microphone Pickups 8.14
Common Comb Filter Sources 8.15
Comb Filters in Stereo Listening 8.16
Spaced Microphone Stereo Techniques 9.1
Introduction 9.1
Near-Coincident Microphone Arrays 9.1
The O.R.T.F. Technique 9.2
The N.O.S. Technique 9.3
The OSS Technique 9.3
The Stereo Ambient Sampling System 9.5
Arrangement of Microphones 9.5
Widely Spaced Microphones 9.5
Lateral Imaging 9.6
Phase-Related Problems 9.9
Observing Stereo Phase Relationships Using an XY
Oscilloscope and Lissajous Patterns 9.9
Spaced Omnidirectional Microphones 9.11
Spaced Directional Microphones 9.12
More about Interference Problems 9.13
The “Decca Tree” 9.14
Two New Species of the Decca Tree 9.16
Flanking and Widely Spaced Microphones 9.17
Multi-Microphone Techniques 10.1
Introduction 10.1
Intensity Stereo Revisited 10.1
The “Panpot” 10.2
The World of Non-Real Time 10.3
The Mixdown 10.4
Basic Rules of Microphone Usage 10.5
Directional Patterns 10.5
Microphone Random Energy Efficiency 10.6
Microphone Distance Factor 10.6
The “Two-to-One” Ratio 10.6
The “Three-to-One” Rule 10.7
Microphone Sensitivity and Sound Pressure Levels 10.7
Multiple-Microphone Concepts 10.8
Multiple Stereo Overlays 10.8
Multiple-Microphone Stereo 10.1
Placement of Spot Microphones 10.12
Creating the Illusion 10.13
Selection of Microphones 10.14
Placement of Microphones 10.15
USING THE NULLS 10.15
One from Many 10.15
Pseudostereo 11.1
Pseudostereo by Frequency Response Differences 11.1
Pseudostereo by Reverberation Chamber 11.3
Pseudostereo by Signal Delay 11.4
Pseudostereo by Complementary Comb Filters 11.4
Pseudostereo by Phase Shifting 11.6
Auditory Spaciousness 12.1
Definition vs. Auditory Spaciousness 12.1
Delayed Sound and Spatial Impression 12.2
Reverberation and Spaciousness 12.2
Spaciousness in Mono 12.3
Spatial Impression by Lateral Reflections 12.4
Spaciousness, a Psychoacoustical Effect 12.4
Reflection Level and Spaciousness 12.4
Reflection Spectrum and Spaciousness 12.5
The Time Window of Spaciousness 12.5
Designing for Spaciousness 12.7
Perception of Distance to Source 12.7
Multi-Dimensional and Surround Sound Systems 13.1
Introduction 13.1
“Fantasound” 13.2
Three-Channel Stereo 13.2
Rear-Channel Sound 13.3
Four-Channel Surround Systems 13.5
Matrixed Quad Systems 13.6
Surround Sound and Ambience Enhancement Systems 13.8
Audio-Follow-Video 13.9
How Many Channels Are Enough? 13.1
How Many Channels Do We Really Need? 13.11
Ambisonics 13.12
Ambisonic Playback 13.15
SoundField Microphone and 5.1 Surround 13.18
Binaural Systems Revisited 13.21
Production Techniques for Surround Sound 13.21
What to Put into the Center Channel 13.21
What to Put into the LFE Channel 13.22
Ambience Recording 13.23
Enhanced Ambience Recording 13.24
Localization in Surround Sound Recordings 13.25
Surround Sound and the Illusion of Reality 13.26
Optimizing the Listening Environment 14.1
Confinement of Sound in an Enclosure 14.2
Axial Mode Resonances 14.3
Tangential and Oblique Modes 14.5
Low Frequency Sound Absorbers 14.6
Mid-High Frequency Region and Delay Effects 14.8
Reflections on and in the Listening Room 14.8
Reflections and the Auditory System 14.9
Effect of Early Reflections 14.1
Diffusion of Sound 14.1
Stereo Geometry 14.11
Low-Frequency Reflections from Nearby Surfaces 14.12
Size of the Listening Area 14.13
Room treatment: low-frequency region 14.13
Room Treatment: Mid-High Frequency Region 14.14
Summary 14.16
British Patent Specification No. 394,325 by A.D. Blumlein A.1
Introduction A.1
Improving the Spatial Illusion A.1
Spatial Perception A.1
Microphone Techniques A.2
Surround Sound A.2
The Stereo Phonograph Record A.2
Stereo Radio Transmission A.2
Acknowledgment A.2
British Patent # 394,325 A.3
Application Date: Dec. 14, 1931 A.3
Complete Accepted: June 14, 1933 A.3
Complete Specifications A.3
Improvements in and relating to Sound-transmission,
Sound-recording and Sound-reproducing Systems A.3
Glossary G.1