Some aspects of the psychophysics of the vibrato

The vibrato is roughly defined as the rapid pulsating effect heard in singing. The work reported in this paper is the result of an attempt to apply the traditional psychophysical approach to the vibrato. The apparatus adopted for the study consisted essentially of a siren disc, except that the disc intercepted a beam of light shining on a photo-electric cell instead of the customary blast of air. By repeatedly counting the number of beats in a given interval of time the accuracy of the apparatus was determined. The tone produced by the apparatus was also read on the Seashore tonoscope. It can be seen that if the holes on one side of the disc are slightly closer together than those on the other side, a frequency vibrato will be produced. The frequency of the sound wave will be higher when the closely spaced holes pass the photo-electric cell than when the more widely separated holes pass this point. The number of vibrato pulsations per second will be determined by the number of revolutions of the disc in a second. There are large individual differences in the ability to hear a frequency vibrato. There are large individual differences in the ability to hear an energy vibrato. The results of the intensive series indicate that the threshold frequency vibrato is not significantly influenced by the rate of the vibrato between the rates of five and eight vibrato pulsations per second. A vibrato with a superimposed energy may tend to cancel a very small frequency vibrato, but the effect is probably so slight as to be of no importance in music. (PsycINFO Database Record (c) 2016 APA, all rights reserved)