Page 15 - The Master Handbook Of Acoustics
P. 15
xiv CONTENTS
Chapter 14 The Schroeder Diffusor 289
Schroeder’s First Acoustic Diffusor 290
Maximum-Length Sequences 292
Reflection Phase-Grating Diffusors 292
Quadratic-Residue Diffusors 293
Primitive-Root Diffusors 296
Quadratic-Residue Applications 298
Performance of Diffraction-Grating Diffusors 298
Expansion of the QRD line 304
Solving flutter problems 304
Application of fractals 306
Diffusion in three dimensions 308
Acoustic concrete blocks 309
Measuring diffusion efficiency 311
Comparison of Gratings with Conventional
Approaches 312
Chapter 15 Modal Resonances in Enclosed Spaces 317
Resonance in a Pipe 318
Bathroom Acoustics 319
Reflections Indoors 320
Two-Wall Resonance 322
Waves vs. Rays 322
Frequency Regions 323
Dividing the Audio Spectrum 325
Wave Acoustics 326
Mode calculations—An example 328
Experimental Verification 331
Mode Identification 331
Mode Decay 333
Mode Bandwidth 334
Mode Pressure Plots 339
Modal Density 341
Mode Spacing and Coloration 342
Experiments with Colorations 344
Simplified Axial Mode Analysis 346
