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Harvey Fletcher (September 11, 1884 – July 23, 1981) was an American physicist. Known as the "Father of stereophonic sound" he is credited with the invention of the audiometer[dubious] and hearing aid.[1] He is remembered as a trail-blazing investigator into the nature of speech and hearing, and for his numerous contributions in acoustics, electrical engineering, speech, medicine, music, atomic physics, sound pictures, and education.

Early career[]

Fletcher was born in Provo, Utah. He graduated from Brigham Young High School in 1904. He enrolled at Brigham Young University (BYU) and graduated in 1907 with a bachelor's degree. As a graduate student at the University of Chicago, his dissertation research was on methods to determine the charge of an electron. This included the now famous Millikan oil drop experiment commonly attributed to his advisor and collaborator, Robert Millikan. Professor Millikan took sole credit, in return for Fletcher claiming full authorship on a related result for his dissertation.[2] Millikan went on to win the 1923 Nobel Prize for Physics, in part for this work, and Fletcher kept the agreement a secret until his death.[3]

Later years[]

Among the work that he is best known for are Fletcher's contributions to the theory of speech perception. He showed that speech features are usually spread over a wide frequency range, and developed the articulation index to approximately quantify the quality of a speech channel.[4] He also developed the concepts of, equal-loudness contours, loudness scaling and summation, and the critical band.[5] As Director of Research at Bell Labs, he oversaw research in electrical sound recording, including more than 100 stereo recordings with conductor Leopold Stokowski in 1931-2.[6][7]

Much of his research is considered to be authoritative, and his books, Speech and Hearing and Speech and Hearing in Communication, are landmark treatises on the subject.


Dr. Fletcher was elected an honorary fellow of Acoustical Society of America in 1949, the second person to receive this honor after Thomas Edison. He was president of the American Society for Hard of Hearing, an honorary member of the American Otological Society and an honorary member of the Audio Engineering Society. In 1924 he was awarded the Louis E. Levy Medal for physical measurements of audition by the Franklin Institute. He was President of the American Physical Society which is the leading Physics society in America. In 1937 he was elected vice-president of the American Association for the Advancement of Science. He was a member of the National Academy of Sciences. He was also a member of the National Hearing Division Committee of Medical Sciences. He was given the Progress Medal Award by the American Academy of Motion Pictures, in Hollywood. For eight years he acted as National Councilor for the Ohio State University Research Foundation.

Fletcher was the Founding Dean of the BYU College of Engineering (now the Ira A. Fulton College of Engineering and Technology).

He died on July 23, 1981, after a stroke.


  1. Signals, sound, and sensation By William M. Hartmann
  2. Template:Cite magazine
  3. Harvey Fletcher (June 1982). My Work with Millikan on the Oil-drop Experiment. Physics Today: 43.
  4. Jont B. Allen (2005). Articulation And Intelligibility, Morgan & Claypool.
  5. William Morris Hartmann (1997). Signals, Sound, and Sensation, Springer.
  6. Leopold Stokowski, Dr. Harvey Fletcher and The Experimental Recordings of Bell Laboratories
  7. William Ander Smith, The mystery of Leopold Stokowski. Fairleigh Dickinson Univ Press, 1990, p.175.

External links[]

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