|Serway, Raymond A., Faughn, Jerry S. "Sound" College Physics Sixth Edition. Pacific Grove, C:. Brooks/Cole-Thompson Learning 2003.||20–12,000 Hz|
|Sound. Encyclopedia Britannica. Encyclopedia Britannica Premium Service. 23 May 2005.||"The frequency range of human hearing extends over three orders of magnitude, from about 20 hertz to about 20,000 hertz, or 20 kilohertz."||20–20000 Hz|
|Hamlin, Peter. Basic Acoustics for Electronic Musicians. St. Olaf College. January 1994, January 1997, January 1999.||"The human ear can hear frequencies ranging from about 20 cps. to about 20,000 cps (although an individual might have a considerably smaller range)."||20–20000 Hz|
|Fjeldsenden, Bjarne. Translation of Visual Information into Auditory Codes. Dept. of Psychology, NTNU. 1970-1972.||"He [Jacobson, H. "The informational capacity of the human ear." Science, 1950, 112, 143-144.] also calculated the total number of monoaural sounds to be 330,000."||330,000
|Homer, Jacobson. The Informational Capacity of the Human Ear. Department of Chemistry, Hunter College, NYC. 4 August 1950.||"A published estimate [Stevens, S.S., and Davis, H. Hearing, its psychology and physiology. New York: John Wiley, 1938] gives 330,000 as the approximate total number of monaurally distinguishable tones of all frequencies and intensities."||330,000
A frequency is the number of complete cycles of a periodic process occurring per unit time. In this study, the frequency was found in Hertz or c.p.s. (cycles per second, an older unit), the major units for measuring frequency. Frequency is affected by the wavelength and the speed of the sound. Frequency can be used in everyday life. The pitch of a person's voice can be measured, the pitch of a car's horn can be determined, the intensity of a fire alarm can be found, etc.
Sound frequencies are longitudinal waves. These waves travel parallel to the direction of energy transport. An example of a longitudinal wave is a stretched slinky in the horizontal direction. The first of the coils vibrate horizontally. Crests and troughs characterize sound waves. Crests are the upper parts of the wave and they indicate condensations. Troughs indicate rarefactions and are the lower parts of the wave.
The audible range of sound frequencies are known as ultrasonic. Depending on the environment one was raised in, the number of frequencies the ears will distinguish can be determined. A person raised in the city will have a low tolerance for noise. He would have a small range of distinguished frequencies due to the loud environment he was raised in. The maximum number of frequencies a human ear is able to distinguish is 330,000 frequencies. These frequencies range from 20 Hz to 20,000 Hz.
Source: Audiology Awareness
Agatha Cwalina -- 2005