CHAPTER VI

RECORDING

59. Historical.-Just when sound was first recorded is not known, but it seems that the Chinese, who were first to devise means of printing, making gun powder and many of the other things which we call modern inventions, were the first to record sound about 4000 B.C. Practically nothing is known of the method they used as they did not keep a record of the details of the device. The story is that a Chinese prince, wishing to communicate with a friend in some disredt province without making the journey himself, would speak into a teak-wood box while turning a crank in the side of it. A courier would then carry the box to the prince's friend, who would, upon turning the crank, hear the reproduced sound message from the prince as it issued forth from a hole in the box. It is characteristic of that gifted race that no effort was made to exploit their discoveries, and it was not until after 6000 years, when Edison rediscovered a method of recording sound, that it came into general use. Edison discovered that indentations on a piece of lead foil could be used to actuate a diaphragm and produce sound. With characteristic resourcefulness, Edison set about developing this discovery, and in a short time produced a commercial machine which now goes by the name of "Phonograph."

Until recently the original sound energy of the source was used to actuate the stylus (cutting point) in making records. This required considerable sound energy, so that records could only be made in a special studio, and even with favorable conditions it was not possible to produce records which gave both faithful reproduction and ample volume. The records produced by this method were, therefore, a compromise between faithful reproduction and volume. The present method used by all up to date record producers employs electricity. The sound energy is first converted. into electrical energy, amplified in vacuum tube amplifiers, and the electrical energy is then used to actuate the mechanism which cuts the impression on the record. With this method no sacrifice in faithfulness is necessary to obtain the desired volume, with the result that extremely faithful reproductions are now possible from disc.

60. Methods of Recording Sound.-At present there are two basic methods of sound recording. One method is that of cutting a groove in a wax disc and the other is a photographic impression on film. The methods of recording on wax discs by different producers are very similar although there are slight differences in the apparatus used. There are two fundamentally different kinds of recording on film. One is called the variable area recording used by Photophone; the other is called variable density, and is used by Western Electric, Movietone, and others.

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