342 



INDEX 



Phonograph, reproducing system, 315 

 "Pi " networks, 69 

 Piezoelectric, driving system, 109 

 microphone, 



diaphragm actuated, 180 

 direct actuated, 182 

 pickup, 235 



telephone receiver, 230 

 Pipes, closed, 47, 84 



open, 47, 84 

 Piston, vibrating, directional, 29 



impedance, 80 

 Pistonphone, 246 

 Pitch, 322 

 Plane waves, 7 

 amplitude, 9 

 particle velocity, 9 

 pressure, 9 

 Plate, circular clamped, 42 

 Point source, 19 

 Poisson's ratio, table, 48 

 Potential energy, 55 



Power, handling capacity of loud speak- 

 ers, 113, 163, 164 

 output of, loud speakers, 113, 163, 164 

 musical instruments, 328 

 speech, 328 

 Pressure, gradient microphone, 189 

 microphone, 172 

 sound, effective, 6 

 instantaneous, 6 

 maximum, 6 

 peak, 6 

 Public address system, 292 

 Pulsating sphere, impedance, 81 



Quantities, table, acoustical, 76 

 electrical, 76 

 mechanical, 76 



Radiation resistance, 80, 81, 83 

 Radio, receiver operating in, automobile, 

 299 

 living room, 298 

 sound reproducing system, 314 

 Rayleigh disk, 249 

 Reactance, acoustical, 59 

 electrical, 58 



mechanical, 59 

 Reflector, 213 

 Refraction, 17 

 Resistance, acoustical, 59 



electrical, 58 



mechanical, 59 



networks, 67 

 Resonant frequency, 59 



bars, longitudinal, 44 

 torsional, 46 

 transverse, 38 



definition, 59 



membrane, circular, 40 



one degree of freedom, 54 



plate, circular, 42 



pipes, 47 



string, 36 

 Response characteristics, (see ears, loud 

 speakers, microphones, tele- 

 phone receivers, testing) 

 Reverberation time, 274, 279, 290, 308 

 Ribbon microphone, 186, 194 

 Rochelle salt, (see piezoelectric) 

 Rotating microphone, 260 



Screen, motion picture, 285 

 Seismic detectors, 243 

 Sirens, 242 

 Sht, narrow, 78 

 Sound, 2 



distribution loud speaker, 143 

 energy density, 14 

 intensity, 14 

 pressure, effective, 6 

 instantaneous, 6 

 maximum, 6 

 peak, 6 

 Source, circular, ring, 28, 29 

 surface, 29 

 curved, line, 25 



surface, 32 

 double, 21 



exponential horn, 31 

 point, 19 

 straight line, 24 

 Speech, artificial larynx, 318 

 frequency range, 326 

 mechanism, 318 



