Quick Facts
Born:
Sept. 11, 1884, Provo, Utah, U.S.
Died:
July 23, 1981, Provo (aged 96)
Notable Works:
“Speech and Hearing”

Harvey Fletcher (born Sept. 11, 1884, Provo, Utah, U.S.—died July 23, 1981, Provo) was a U.S. physicist, a leading authority in the fields of psychoacoustics and acoustical engineering.

Fletcher graduated from Brigham Young University in Provo, Utah, in 1907 and received a Ph.D. in physics from the University of Chicago in 1911. In 1916 he joined the staff of Bell Telephone Laboratories, where he worked for 33 years, primarily in the fields of speech, music, and hearing. Much of his work on the fundamentals of psychoacoustics is described in his book Speech and Hearing (1922).

Fletcher’s research group developed and demonstrated two separate but related methods for reproducing sound: binaural sound reproduction and stereophonic reproduction. He and his team gave the first public demonstration of stereophonic sound in 1934 in New York City. In 1949 he moved to Columbia University, where he established a department of acoustical engineering. In 1952 he was appointed director of research at Brigham Young University, becoming dean of the College of Physical Engineering Sciences (1954) and professor of physics (1958). In 1974 he became professor emeritus, continuing his research in acoustics until a few weeks before his death.

Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.
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This article was most recently revised and updated by Encyclopaedia Britannica.

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acoustics, the science concerned with the production, control, transmission, reception, and effects of sound. The term is derived from the Greek akoustos, meaning “heard.”

Beginning with its origins in the study of mechanical vibrations and the radiation of these vibrations through mechanical waves, acoustics has had important applications in almost every area of life. It has been fundamental to many developments in the arts—some of which, especially in the area of musical scales and instruments, took place after long experimentation by artists and were only much later explained as theory by scientists. For example, much of what is now known about architectural acoustics was actually learned by trial and error over centuries of experience and was only recently formalized into a science.

Other applications of acoustic technology are in the study of geologic, atmospheric, and underwater phenomena. Psychoacoustics, the study of the physical effects of sound on biological systems, has been of interest since Pythagoras first heard the sounds of vibrating strings and of hammers hitting anvils in the 6th century bc, but the application of modern ultrasonic technology has only recently provided some of the most exciting developments in medicine. Even today, research continues into many aspects of the fundamental physical processes involved in waves and sound and into possible applications of these processes in modern life.

Sound waves follow physical principles that can be applied to the study of all waves; these principles are discussed thoroughly in the article mechanics of solids. The article ear explains in detail the physiological process of hearing—that is, receiving certain wave vibrations and interpreting them as sound.