Master Handbook of Acoustics by Everest, F. Alton -- Read -- Imperial Library of Trantor

Index

Introduction 1 Fundamentals of Sound The Sine Wave Sound in Media

Particle Motion Propagation of Sound Speed of Sound

Wavelength and Frequency Complex Waves

Harmonics Phase Partials

Octaves Spectrum Electrical, Mechanical, and Acoustical Analogs 2 Sound Levels and the Decibel Ratios versus Differences

Expressing Numbers

Logarithms Decibels Reference Levels Logarithmic and Exponential Forms Compared Acoustic Power Using Decibels

Example 1: Sound-Pressure Level Example 2: Loudspeaker SPL Example 3: Microphone Specifications Example 4: Line Amplifier Example 5: General-Purpose Amplifier Example 6: Concert Hall Example 7: Combining Decibels

Measuring Sound-Pressure Level Sine-Wave Measurements 3 Sound in the Free Field The Free Field Sound Divergence Sound Intensity in the Free Field Sound Pressure in the Free Field

Examples: Free-Field Sound Divergence

Sound Fields in Enclosed Spaces

Hemispherical Field and Propagation

4 The Perception of Sound Sensitivity of the Ear Ear Anatomy

The Outer Ear Directional Cues: An Experiment The Ear Canal The Middle Ear The Inner Ear Stereocilia

Loudness versus Frequency

Loudness Control Area of Audibility

Loudness versus Sound-Pressure Level Loudness and Bandwidth Loudness of Impulses Audibility of Loudness Changes Pitch versus Frequency

An Experiment in Pitch The Missing Fundamental

Timbre versus Spectrum Localization of Sound Sources Binaural Localization Law of the First Wavefront

The Franssen Effect The Precedence Effect

Perception of Reflected Sound The Cocktail-Party Effect Aural Nonlinearity Subjective versus Objective Occupational and Recreational Deafness Summary 5 Signals, Speech, Music, and Noise Sound Spectrograph Speech

Vocal Tract Molding of Speech Formation of Voiced Sounds Formation of Unvoiced Sounds Frequency Response of Speech Directionality of Speech

Music

String Instruments Wind Instruments Nonharmonic Overtones

Dynamic Range of Speech and Music Power in Speech and Music Frequency Range of Speech and Music Auditory Area of Speech and Music Noise

Noise Measurements Random Noise White and Pink Noise

Signal Distortion

Harmonic Distortion

Resonance Audio Filters 6 Reflection Specular Reflections

Flutter Echoes

Doubling of Pressure at Reflection Reflections from Convex Surfaces Reflections from Concave Surfaces Reflections from Parabolic Surfaces

Whispering Galleries

Standing Waves The Corner Reflector Mean Free Path Perception of Sound Reflections

The Effect of Single Reflections Perception of Spaciousness, Images, and Echoes Effect of Angle of Incidence, Signal Type, and Spectrum on Audibility of Reflection

7 Diffraction Wavefront Propagation and Diffraction Wavelength and Diffraction Diffraction of Sound by Obstacles Diffraction of Sound by Apertures Diffraction of Sound by a Slit Diffraction by the Zone Plate Diffraction around the Human Head Diffraction by Loudspeaker Cabinet Edges Diffraction by Various Objects 8 Refraction The Nature of Refraction Refraction of Sound in Solids Refraction of Sound in the Atmosphere Refraction of Sound in Enclosed Spaces Refraction of Sound in the Ocean 9 Diffusion The Perfectly Diffuse Sound Field Evaluating Diffusion in a Room

Steady-State Measurements

Decay Beats Exponential Decay Spatial Uniformity of Reverberation Time Geometrical Irregularities Absorbent in Patches Concave Surfaces Convex Surfaces: The Polycylindrical Diffuser Plane Surfaces 10 Comb-Filter Effects

Comb Filters Superposition of Sound Tonal Signals and Comb Filters

Combing of Music and Speech Signals Combing of Direct and Reflected Sound

Comb Filters and Critical Bands Comb Filters in Multichannel Playback Reflections and Spaciousness Comb Filters in Microphone Placement Comb-Filter Effects in Practice: Six Examples Estimating Comb-Filter Response

11 Reverberation

Growth of Sound in a Room Decay of Sound in a Room Idealized Growth and Decay of Sound Calculating Reverberation Time

Sabine Equation Eyring-Norris Equation Air Absorption

Measuring Reverberation Time

Impulse Sources Steady-State Sources Measuring Equipment Measurement Procedure

Reverberation and Normal Modes

Analysis of Decay Traces Mode Decay Variations Frequency Effect

Reverberation Characteristic

Reverberation Time Variation with Position

Decay Rate and the Reverberant Field Acoustically Coupled Spaces Electroacoustically Coupled Spaces Eliminating Decay Fluctuations Influence of Reverberation on Speech Influence of Reverberation on Music Optimum Reverberation Time

Bass Rise of Reverberation Time Initial Time-Delay Gap Listening Room Reverberation Time

Artificial Reverberation Reverberation Time Calculations

Example 1: Untreated Room Example 2: Modified Room

12 Absorption

Dissipation of Sound Energy Absorption Coefficients

Reverberation Chamber Method Impedance Tube Method Tone-Burst Method

Mounting of Absorbents Mid/High-Frequency Absorption by Porosity Glass Fiber Insulation Materials

Glass Fiber: Boards Glass Fiber: Acoustical Tile

Effect of Thickness of Absorbent Effect of Airspace behind Absorbent Effect of Density of Absorbent Open-Cell Foams Drapes as Sound Absorbers Carpet as Sound Absorber

Effect of Carpet Type on Absorbance Effect of Carpet Underlay on Absorbance Carpet Absorption Coefficients

Sound Absorption by People Sound Absorption in Air Panel (Diaphragmatic) Absorbers Polycylindrical Absorbers

Poly Construction

Bass Traps: Low-Frequency Absorption by Resonance Helmholtz (Volume) Resonators Perforated Panel Absorbers Slat Absorbers Placement of Materials Reverberation Time of Helmholtz Resonators

Reducing Room Modes with Absorbers

Increasing Reverberation Time Modules

13 Modal Resonances

Early Experiments and Examples Resonance in a Pipe Reflections Indoors Two-Wall Resonance Frequency Regions Room-Mode Equation

Mode Calculations—An Example Experimental Verification

Mode Decay Mode Bandwidth Mode Pressure Plots Mode Density Mode Spacing and Timbral Defects

Audibility of Timbral Defects

Optimal Room Shape

The Bonello Criterion

Splaying Room Surfaces

Nonrectangular Rooms

Controlling Problem Modes Simplified Axial Mode Analysis Summary

14 Schroeder Diffusers

Experimentation Reflection Phase-Grating Diffusers Quadratic-Residue Diffusers Primitive-Root Diffusers Performance of Diffraction-Grating Diffusers Reflection Phase-Grating Diffuser Applications

Flutter Echo Application of Fractals Diffusion in Three Dimensions Diffusing Concrete Blocks Measuring Diffusion Efficiency

Comparison of Gratings with Conventional Approaches

15 Adjustable Acoustics

Draperies Adjustable Panels: Absorption Hinged Panels Louvered Panels Absorption/Diffusion Adjustable Panels Variable Resonant Devices Rotating Elements Portable Units

16 Control of Interfering Noise

Approaches to Noise Control Airborne Noise

Transmission Loss

Effect of Mass and Frequency

Coincidence Effect Separation of Mass

Composite Partitions Porous Materials Sound Transmission Class Comparison of Wall Structures Sound-Insulating Windows Sound-Insulating Doors Structureborne Noise

Noise Transmitted by Diaphragm Action

Floating Floors

Floating Walls and Ceiling Noise and Room Resonances

Noise Standards and Specifications

17 Noise Control inVentilating Systems

Selection of Noise Criterion Fan Noise Machinery Noise and Vibration Air Velocity Natural Attenuation Duct Lining Plenum Silencers Packaged Attenuators Reactive Silencers Tuned Silencers Duct Location ASHRAE Active Noise Control Some Practical Suggestions

18 Acoustics of Listening Rooms

Playback Criteria Peculiarities of Small-Room Acoustics

Room Size and Proportion Reverberation Time

Low Frequency Considerations

Modal Anomalies Control of Modal Resonances Bass Traps for the Listening Room

Mid-High Frequency Considerations

Identification and Treatment of Reflection Points Lateral Reflections and Control of Spaciousness

Loudspeaker Placement

19 Acoustics of Small Recording Studios

Ambient Noise Requirements Acoustical Characteristics of a Studio

Direct and Indirect Sound Role of Room Treatment

Room Modes and Room Volume

Mode Analysis for Different Room Sizes

Reverberation Time

Reverberation in Small Rooms Optimal Reverberation Time

Diffusion Noise Studio Design Example

Absorption Design Goal Proposed Room Treatment

20 Acoustics of Control Rooms

Initial Time-Delay Gap Live End-Dead End Specular Reflections versus Diffusion Low-Frequency Resonances in the Control Room Initial Time-Delay Gaps in Practice Loudspeaker Placement and Reflection Paths The Reflection-Free-Zone Control Room Control-Room Frequency Range Outer Shell and Inner Shell of the Control Room

21 Acoustics of Audio/Video Rooms

Design Factors Acoustical Treatment Audio/Video Work Place Example

Appraisal of Room Resonances Control of Room Resonances Absorption Calculation Proposed Treatment Specialized Treatment

Voice-Over Booth

Dead versus Live Ambience Early Reflections

Live End-Dead End Voice Studio

22 Acoustics of Large Halls

Essential Design Criteria Reverberation and Echo Control Hall Design for Speech

Volume Hall Geometry Absorption Treatment Ceiling, Walls, and Floor

Speech Intelligibility

Speech Frequencies and Duration Subject-Based Measures Analytical Measures

Concert Hall Acoustical Design

Reverberation Clarity Brilliance Gain Seating Capacity Volume Spaciousness Apparent Source Width Initial Time-Delay Gap Bass Ratio and Warmth

Concert Hall Architectural Design

Balcony Ceiling and Walls Raked Floor

Virtual Image Source Analysis Hall Design Procedure

Case Studies

23 Acoustic Distortion

Acoustic Distortion and the Perception of Sound Sources of Acoustic Distortion

Coupling of Room Modes Speaker-Boundary Interference Response Comb Filtering Diffusion Diffusion Measurement

Design Approach

24 Room Acoustics Measurement Software

Acoustic Measurements Basic Analysis Instruments Time-Delay Spectrometry Techniques Maximum-Length Sequence Techniques AcoustiSoft ETF Program

Frequency-Response Measurements Resonance Measurements Fractional-Octave Measurements Energy-Time Curve Measurements Reverberation Time

25 Room Optimizer

Modal Response Speaker-Boundary Interference Response Optimization Theory of Operation

Prediction of Room Response Optimizing Procedure Cost Parameter

Optimization Procedure Results of Operation

Stereo Pair Stereo Pair with Two Woofers per Loudspeaker 5.1-Channel Home Theater with Dipole Surrounds 5.1-Channel Home Theater with Matched Satellites Subwoofer

Summary

26 Room Auralization

History of Acoustic Modeling The Auralization Process

Scattering Coefficients Receiver Characterization Echogram Processing Room Model Data Room Model Mapping Binaural Playback

Summary Biblography Appendix Glossary Index

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