On the Shortest Sounds Perceived by the Ear.

(A. Stefanini. Quante vibrazioni occorrono per riconoscere un suono? Il nuovo Cimento Ser. 6. Vol. 13. Fasc. 2—3 p. 65—1917).

For understanding the phenomena of resonance in the middle ear, the study of the perception of short sounds that produce the impression of sounds of a definite pitch appears very important. As early as 1830 Savart began these studies, which were continued by Villari, Maragnoni, Mach, Exner, Pfaundler, Auerbach, Götz-Martin, Kohlrausch, Perroune Yeo, Meyer, Abraham, Brühl and, finally, Leimbach, and showed that, for sounds of different pitch (from 100 to 4000 vibrations), from two vibrations (a sound lasting from \(\frac{1}{50}\) to \(\frac{1}{2000}\) of a second) to 16 vibrations are sufficient for the sound to be more or less clearly determined in pitch. The experiments of Abraham and Brühl showed that, with an increase in the pitch of the sound, an increase in the number of separate vibrations (the duration of action of the sound) is necessary for the sound to be quite clearly determined in pitch.

In Stefanini’s work we find a description of five methods for obtaining short sounds of definite pitch (the number of vibrations per second ranged from 64 to 4096, and the number of separate waves necessary to obtain a definite impression of pitch ranged from 2 to 80), and, with a rise in the pitch of the sound, the total number of waves necessary for a definite sensation increased.

As yet unpublished observations of Lazarev, reported at the Scientific Institute, have shown that, if the sounds are sufficiently strong, then in very broad limits only two condensations and rarefactions are needed to create the impression of a sound of definite pitch. A decrease in the strength of the sound requires an increase in the number of waves brought to the ear.

P. Lazarev.