Applications of the Buchmann-Meyer Effect in the Calibration of Phonograph Recording and Reproducing Equipment

Abstract

Buchmann and Meyer have shown that the optical patterns reflected from a modulated phonograph record can be evaluated quantitatively in terms of the stylus-point velocity at the time of recording. If a record is illuminated with parallel rays of light, the width of the luminous band is directly proportional to the lateral velocity. Thus, the over-all frequency-response characteristic of a recording mechanism may be readily and quickly determined. Also, the characteristic of a reproducing system may be determined from a record of known lateral velocities at various frequencies. The effect may also be used to determine the magnitude of recording turntable speed fluctuations, surface noise level of a record, and the state of the division of the particles constituting the surface of a record. The paper develops the theory of the effect, and its practical applications will be demonstrated in the University recording laboratories.