| Popis: |
The importance of constant record speed in machines used for reproduction of music was realized by Thomas A. Edison and many other pioneers in sound recording. Crude performance from other standpoints made it hardly worth while for the earlier workers to attempt to obtain extremely high standards of speed constancy. — The flyball type of phonograph governor came into the picture and has been worked so well that it has not even yet been superseded, although with synchronous motor drives for certain types of equipment the governor is no longer necessary. — Recording sound photographically probably began with the work of Alexander Graham Bell who made records on glass disks; but not until long celluloid films were available and the motion picture thoroughly established did photographic sound recording become a competitor with the disk. As late as 1930, there were many engineers who advocated the disk for sound-picture work. While the same general principle applies to both mechanical and photographic records, the latter involves certain additional problems. — Among the earlier workers in this field, the expedients adopted by C. A. Hoxie and C. L. Heisler, of General Electric Company, deserve recognition. The paper gives brief descriptions and discussions of a number of ingenious arrangements for improving speed constancy that have been employed by various inventors and engineers. Some of these expedients have been applied to record turntables and some to film equipment. |
