Architectural Acoustics Illustrated

MICHAEL ERMANN is an associate professor at Virginia Tech's School of Architecture + Design, and a past undergraduate architecture program co-chairman. He teaches architectural acoustics, design studio, and environmental building systems. Prior to joining the VT faculty, Professor Ermann was an acoustical consultant at Artec in New York, NY and Siebein Associates in Gainesville, FL.

Acknowledgments xi Introduction xiii 1. Basic Theory 1 Sound Level 2 Sound Level 2 Source Path Receiver 4 Measuring Sound Level 5 Measuring Sound Level 8 Multiple Sound Sources 9 Decibel Addition 10 Sound Propagation 11 Sound Propagation 11 Directivity 12 Sound Frequency 13 Frequency 13 Octave Bands 17 Sound Level Perception and Frequency 19 A-Weighted Decibels 20 The Special Case of Low-Frequency Sound 22 2. Sound Absorption 25 Principles of Absorptive and Reflective Surfaces 26 Absorption Coefficient 27 Types of Sound Absorbers 29 Room Constant 33 Room Average Absorption 33 Noise Reduction Coefficient (NRC) 36 Sound Absorption Data 38 3. Room Acoustics 57 Room Acoustics Qualities 58 Impulse Response 58 Reverberance 60 Optimal Reverberation Time 65 Clarity 66 Variable Acoustics 70 Reverberation Time Calculation Checklist 74 Room Shaping for Speech and Music 75 Loudness 76 Balconies 80 Sightlines 82 Warmth 83 Concert Hall Types 85 Spatial Impression 87 Intimacy 94 Diffusion 95 Theater Planning 97 Stage Acoustics 97 Orchestra Pits 101 What Makes a Good Room for Music? 102 Performance Venue Seats 106 Acoustic Defects 109 Acoustic Defects 109 Performance Venues 114 Room Acoustics History 114 Performance Venues to Visit 117 Design Checklists 118 Rooms for Unamplified Music Performance Checklist 118 Other Types of Rooms Checklist 119 Sound System Design 123 Electronic Sound Reinforcement 123 4. Noise Control 131 Sound Isolation Principles 132 Apartment Layout Graphic Quiz 132 Flanking 133 Flanking Graphic Checklist 134 Flanking Noise Checklist 134 Measures of Airborne Sound Isolation 140 Transmission Loss (TL) 140 Sound Transmission Class (STC) 142 How to Measure Sound Transmission Class (STC) 144 Target STC Ratings 146 Noise Reduction (NR) 147 Achieving Higher Acoustical Privacy 148 Background Noise 152 Background Noise 152 Noise Criteria (NC) 153 Speech Intelligibility and Noise 155 Open-Plan Office Acoustics 157 Sound Transmission Loss Data 162 Noise Reduction Example Problem 175 Air-Structure-Air Flanking 178 Acoustic Privacy Checklist 179 Apartment Layout Quiz Answer 180 Door and Window Sound Isolation 182 Doors 182 Noise Isolation and Windows 184 Impact Noise 185 Impact Noise Isolation 185 How to Measure IIC 190 Impact Noise Checklist 192 Recommended Floor-Ceiling Assemblies 195 Resiliently Mounted Room Surfaces 197 Community Noise 202 Principles of Community Noise 202 Building-in-Building Design 202 Noise Sources 204 Community Noise Research 207 Community Noise Example Problem 208 Outdoor Barriers 209 Outdoor Barriers Checklist 210 Outdoor Barrier Example Problem 212 Wind Turbine Noise 214 Community Noise Checklist 215 Mechanical System Noise 217 Principles of Mechanical System Noise 217 Ducted Fan Noise 220 Mechanical Room Graphic Checklist 224 Ducted Air Turbulence Noise 225 Vibration Isolation 229 Mechanical Noise Checklist 232 Plumbing Noise 237 Isolating Pipes from Structure 238 Plumbing Noise Checklist 239 Index 243