抄録
In this abstract, extent of vibrato means the amount of pitch change in the pulsation, rate of vibrato means the number of vibrato pulsations per second, the intermediate zone means the zone between the upper and lower extremes of pitch change. Extent, distance, middle of the intermediate zone, etc, are used to refer to the size of interval expressed in cents (See Table V; 100 cents=one equal semitone), but not to the vibraticn difference.
Figures and tables noted refer to those inserted in the Japanese text, pp.793-846.
Introduction and problems: The vibrato, as often met in music, is in its physical nature, mere pulsation of vibration frequency. To take an illustration from string music, the player, by rolling his finger tip on the string, and thus alternately lengthening and shortening the length of the vibrating string, produces the vibrato. Thus the vibrato is, on its physical side, nothing more than periodical pulsation of frequency (not to speak of the intensity vibrato), but on its phenomenal side, it is more than mere fluctuation of a tone; it has one salient pitch more or less distinct, in addition to the pulsating effect. This fact presents a set of problems very important for the psychology of perception as well as for psychological acoustics.
The present study was undertaken to treat some of these problems concerning this principal pitch, which can be stated in the form of the following questions.
What is the necessary condition for producing the principal pitch in the vibrato?
Is the principal pitch heard as an intertone? Or does it coincide with one of the two extremes of the vibrato? What is its exact position? Is there any law concerning its position?
In what phenomenological ways the principal pitch comes into existence?
Does the position of the principal pitch changewith the rate of the vilbrato?
Is the principal pitch perceived only in the vibrato and not in the trill?
What is the difference between the vibrato and trill concerning the principal pitch?
Apparatus: The main apparatus used in this study was a vibrato generator which consisted of an ellectric tube oscillator and a series of rotating variable condensers, as shown in Figs. 3 and 4, pp.797 and 798. As the frequency of the vibrations from an oscillation circnit is defined bv the formula ƒ=1/2π√lc, so by changing the capacity c periodically between the two known values, other factors being kept constant, we can get periodical pulsation of a tone or the vibrato. For attaining this, we rotated the condensers by meahs of a moter.
Conditions in general: The form of the vibrato or the objective course of interval change in the vibrato used in this study is shown in Fig. 5; and the pitch regions in which the vibratos were observed were at 1500, 1100, and 900 cycles (for details, see Tables VI-VIII). The extent of the vibratos used in the experiments is shown in Table IV. Three observers, Wd., Tk. and Hr. were used in all series of experiments, whose discrimination threshold for pitch does not exceed 2 cycles at these regions.
Experiments: The present study consisted of a series of seven experiments. In Exp. I, the rate was changed from 1.5 to 6.0 p.s., the extents being constant, and the subjects were asked to report what they heard and especially to determine whether there was definite pitch or not in the sound they heard.
In Exp. II, the extent was changed in five stages from 12 to 48 cents, the rate being kept constant at three different stages. In Exp.
