CONTENTS XV 



Chapter Page 



K. Radio Receiver Operating in an Automobile 299 



L. Absorption of Sound in Passing Through Air 300 



M. Sound Transmission Through Partitions 301 



N. Nonlinear Distortion Generated in a Plane Sound Wave 302 



12.3 Collection of Sound 303 



A. Sound Collecting System 303 



B. Broadcasting Studios 307 



C. Reverberation Time of a Broadcasting, Recording and Scoring 



Studio 308 



D. Synthetic Reverberation 309 



12.4 Complete Reproducing Systems 309 



A. Telephone '• 309 



B. Binaural Reproduction 310 



C. Auditory Perspective Reproduction 311 



D. Sound Motion Picture Reproducing System 312 



E. Radio Sound Reproducing System 314 



F. Phonograph Reproducing System 315 



XIII. SPEECH, MUSIC AND HEARING 



13.1 Introduction 317 



13.2 Hearing Mechanism 317 



13.3 Speech Mechanism 318 



A. Artificial Larynx ' 318 



B. Vocoder 319 



13.4 Response Frequency Characteristics of Ears 319 



13.5 Loudness of a Sound 320 



13.6 Change of Pitch With Loudness 322 



13.7 Masking 322 



13.8 NONLINEARITY OF THE EaR 323 



13.9 Effect of Phase Relations Among the Harmonics 324 



13.10 Modulation 324 



13.11 Auditory Localization 325 



13.12 The Frequency and Volume Ranges of Speech and Music and the 

 Effects of Frequency Distortion Upon Reproduced Sound 326 



13.13 Absolute Amplitudes and Spectra of Speech, Musical Instruments 



and Orchestras 328 



13.14 Effect of Nonlinear Distortion Upon the Quality of Reproduced 

 Speech and Music 328 



13.15 Combination Tones and Nonlinear Transducers 331 



13.16 Minimum Perceptible Differences 331 



13.17 Timbre (Tone Quality) 332 



13.18 Noise in Reproducing Systems 333 



13.19 Musical Scale . : 334 



