INDEX 



339 



Efficiency, direct radiator, 112 



horn, 145 

 Electrical, abohm, 58 



analogies, 49 



elements,49, 50, 51,53 



impedance, 58 



reactance, 58 



resistance, 50, 58 



system, one degree of freedom, 54 



three degrees of freedom, 61 



two degrees of freedom, 60 



Electrodynamic driving system, 101 



Electromagnetic driving system, 102 



Elements, acoustical, 50, 51, 52, 53 



electrical, 49, 50, 51, 53 



mechanical, 50, 51, 52, 53 

 Energy density, sound, 14 

 Equation, continuity, 4 



motion, 5, 57 



wave, 4 

 Exponential horn, 31, 89 



directional characteristics, 31 



finite, 91 



infinite, 89 



multiple flare, 96 



Feedback, 135 



Field structure, loud speaker, 143, 171 

 Filters, (see wave filters) 

 Frequency, 3 



fundamental, 3 



range of, music, 326 

 speech, 326 



resonant, 59 



General announce system, 296 

 Generators of sound, (see loud speakers) 



sirens, 242 



whistles, 243 

 Geophysical, (see seismic) 

 Gyration, radius of, 38 



Harmonic, 3 



Head diffraction, 17, 325 



Hearing, aids, 



carbon, 241 



vacuum tube, 241 

 mechanism, 317 



response characteristics, 319 



nonlinearity, 323 

 Helmholtz resonator, 64 

 Horn, cellular, 32 



direct radiator combination, 133 

 directional characteristics, 31, 32 

 equation, 86 

 finite, characteristics, 92 



conical, 90 



exponential, 91 

 general, 85 

 infinite, conical, 88 



exponential, 89 



impedance, 89 



parabolic, 87 

 loud speaker, (see loud speaker horn) 

 manifold sections, 96 

 multiple flare, 96 

 Hot wire microphone, 212 



Impedance, acoustical, 59 

 table, 8 



bridge, 271 



ear, 270 



electrical, 58 



horns, 92 



mechanical, 59 



motional, 102 



orifice, 84 



oscillating sphere, 83 



pipe, 84, 85 



piston, 80 



pulsating sphere, 81 



slit, 78 



tube, 78 

 Inductance, 50 

 Inductor, microphone, 185 



telephone receiver, 232 

 Inertance, 51, 79 

 Inertia, 51 

 Intelligibility, 277 

 Intensity of sound, 14 

 Intercommunicating system, 297 



Kinetic energy, 55 



Labyrinth, 132 

 Lapel microphone, 212 



