Sound motion pictures : from the laboratory to their presentation (1929)

252 SOUND MOTION PICTURES closed that persons differ significantly in their keenness of function. Further, the test shows that there is frequent disparity in the sensibility of the two ears; that high notes are more readily perceived than low ones; that the upper limitation of audition varies considerably for different normal individuals; and that the hearing of men is apparently better than the hearing of women, but that such difference is very slight. The reaction of listeners not musically trained is one of great delight in the simpler compositions. When a composition is intricately constructed and requires mental effort the sound is likely not to be pleasant unless the hearer has been schooled in musical appreciation. It is too remote from his normal background. In the same way the degree to which the listener enjoys an unfamiliar work depends upon the degree of its simplicity. The tone quality of sound, like the pitch, may be accurately measured and may be examined and preserved for comparative study. The principal methods heretofore employed for making such records are the Phon-autograph of Koenig, the phonograph invented by Edison, the telephone of Bell, used in connection with the Oscillograph and the Manometric Flame devised by Koenig and developed by Nichols and Merritt. An interesting way to study sound waves is to be found in the phonograph. We can make the phonograph disk record the waves corresponding to an orchestra or to any kind of sound, simple or complicated, music or mere noise, and the marks made upon the wax by the needle can be studied by means of the microscope or may be greatly magnified and photographed. In addition to these is the Phonodeik devised by Dayton C. Miller, Professor of Physics, in the Case School of Applied Science at Cleveland. By the use of his instrument it is possible to photograph and measure sound waves, both vocal and instru