338 



INDEX 



Circular, ring source, 28 



surface source, 29 

 Collection of sound, 303 



broadcasting studios, 307 



directional microphones, 189, 203, 213, 

 305 



nondirectional microphones, 185, 305 



reverberation time, 274, 280, 290, 308 



synthetic reverberation, 309 

 Combination tones, 331 

 Compliance, mechanical, 52 

 Compound horn, 168 

 Compressibility, 5 

 Condensation, 6 

 Condenser, driving system, 107 



microphone, 177 

 Cone, (see diaphragm) 

 Conical horn, 88, 90 

 Connectors, exponential, 94 

 Consonant sounds, 277, 318 

 Corrective networks, 62 

 Crystal, microphone, 180 



diaphragm actuated, 182 

 direct actuated, 182 



pickup, 235 



telephone receiver, 230 

 Curved, line source, 25 



surface source, 32 

 Cutoff frequency of, exponential horn, 89 



filter, 70 

 Cycle, 3 



Decibels, 15 



Density, various materials, table, 8, 48 

 Diaphragms, loud speaker, 142, 171 

 Difference tones, 331 

 Diffraction, 17 



Dimensions, table, acoustical, 76 

 electrical, 76 

 mechanical, 76 

 Directional, characteristics, circular sur- 

 face, 29 

 curved surface, 32 

 double source, 21 

 exponential horn, 31 

 line, circular, 28 

 curved, 25 

 straight, 24 



piston, 29 

 efficiency, 221 



microphones, 189, 203, 213, 305 

 Direct radiator loud speaker, (see loud 



speaker) 

 Dispersion of sound, 279 



absorption in passing through air, 300 

 articulation, 281 

 general announce system, 296 

 intercommunicating system, 297 

 noise, 291 



nonlinear distortion in plane wave, 302 

 paging system, 296 

 power requirements, 290 

 public address system, 292 

 radio receiver, operating in, automo- 

 bile, 290 

 living room, 298 

 reverberation time, studio, 308 



theatre, 290 

 sound, absorption, 279 

 table, 281 

 motion picture system, 282 

 re-enforcing system, 286 

 transmission through partitions, 301 

 Dissipation, 56 



Distortion, nonlinear, ear, 323 

 loud speaker, 136, 156, 262 

 microphone, 223, 251 

 phonograph, 238 

 subharmonic, 137, 162 

 Doppler effect, 16 

 Double source, 21 

 Driving systems, 101 

 condenser, 107 

 electrodynamic, 101 

 electromagnetic, 102 

 piezoelectric, 109 

 Dynamic, loud speaker, (see direct radia- 

 tor loud speaker) 

 microphone, 183 

 pickup, 238 

 telephone receiver, 230 

 Dyne, 6 



Ear, artificial, 270 

 mechanism, 317 

 response characteristics, 319 



