Combination Tones

Combination Tones

 

tones that arise in a nonlinear acoustic system in the presence of two or more sine-wave sound oscillations. The frequency of combination tones is expressed as a sum (summation tone) or a difference (difference tone) of the primary tones. The combination tones that arise in the human hearing apparatus when it is acted on by a high-intensity sound are called subjective tones (“Tartini tones”). The reason for the formation of such tones is the nonlinearity of the process of sound perception and of the mechanical system of the hearing apparatus. Differential subjective combination tones are of particular importance; because of these tones louder sounds appear to be richer in lower tones. Combination tones arising outside the human ear are called objective; such tones can arise because of nonlinearity of the sound source itself or of the sound-conducting medium. Combination tones are of great significance for the theory of musical instruments; they are also used in studying nonlinear distortions in acoustical apparatus.

REFERENCES

Helmholtz, H. L. F. Uchenie o slukhovykh oshchushcheniiakh kak fizicheskaia osnova dlia teorii muzyki. St. Petersburg, 1875. Chapters 7 and 11. (Translated from German.)
Gorelik, G. S. Kolebaniia i volny, 2nd ed. Moscow-Leningrad, 1959.
References in periodicals archive ?
Combination tones have been known for more than three centuries.
This type of variability is known in physics as a combination tone," said Fei-Fei Jin, professor of Meteorology and co-author of the study.
The unusual wind pattern straddling the equator during an El Nino is such a combination tone between El Nino events and the seasonal march of the sun across the equator," said co-author Axel Timmermann, climate scientist at the International Pacific Research Center and professor at the Department of Oceanography, University of Hawai'i.
It turns out that many climate models have difficulties creating the correct combination tone, which is likely to impact their ability to simulate and predict El Nino events and their global impacts," he added.