Hunt, Frederick Vinton
HUNT, FREDERICK VINTON
(b. Barnesville, Ohio, 15 February 1905; d. Buffalo, New York, 20 April 1972)
Hunt was the youngest of the three children of Fred Hunt and Ella Shipley. The family lived in an agricultural town that was on a major railroad line. His father worked for the First National Bank of Barnesville and eventually became its president. His mother came form a substantial farming family. As a child Hunt received considerable encouragement in his studies from his family and teachers. His brother, Spencer, ten years older, who became an electrical engineer, introduced him to electricity and radio. He received bachelor’s degrees in physics (1924) and electrical engineering 91925) from Ohio State University.
Hunt then entered Harvard, where he remained throughout his career, working in acoustics, especially electroacoustical transduction. Harvard already had a tradition in acoustics, dating at least from Wallace C. Sabine’s studies of reverberation in 1895, that was being carried on by Frederick A. Saunders and George W. Pierce when Hunt arrived as a graduate student. He wrote doctoral dissertations in both physics and engineering. Hunt received the doctoral degree, only one being allowed, in physics (1934) and served on the faculty until he retired in 1971. He held the Gordon McKay professorship of applied physics from 1946 and the Rumford professorship of physics from 1953. He directed the Harvard Underwater Sound Laboratory (1941–1946) and then the Acoustics Research Laboratory.
Hunt’s doctoral dissertation in physics, written under Pierce, was in acoustical reverberation: he developed a technique for determining the decay curves for sound in a room and, by using a frequencymodulated sound source, obtained improved accuracy. In the late 1930’s Hunt and his first doctoral students investigated topics in the field of room acoustics. This work formed the basis for extensive studies of the acoustics of concert halls that his students later pursued.
Hunt’s other doctoral dissertation also dealt with a fundamental topic in acoustics: the measurement of audio frequencies. He developed a direct-reading frequency meter in which a current is proportional to the frequency of the source. This meter extended the limits within which frequency indication was not distorted by amplitude and wave form, and it was capable of responding to rapid variations in the frequency of the signal. This made it suitable for studying the variation of frequency in speech, for example. Used in conjunction with heterodyne methods, the meter also had the potential for measuring and controlling radio frequencies, and the General Radio Company manufactured it in great numbers.
Beginning in 1936, Hunt searched for ways to reduce distortion in reproducing sound from phonograph records. He considered primarily the reproducer (stylus and transducer). Pickup weight, the force of the stylus on the record, in the 1930’s was more than one hundred grams, because the design at the time required that the stylus should be ground while tracking in order to fit the groove. Hunt and J. A. Pierce developed a reproducer with a pickup weight of only five grams that did not need grinding. At about the same time (1938) they also gave a theoretical analysis of the distortion due to the fact that the reproducing stylus, having a different shape, does not follow the trajectory of the cutting stylus exactly. They suggested ways in which this “tracing” distortion could be reduced, one of which involved the use of light forces and a stylus with a much smaller tip (which would, as they noted, permit long-playing records). This analysis led to further theoretical studies by Hunt’s students and others. Over the years Hunt continued to encourage the development of lighter pickups, and in the 1960’s he was attempting to make one that weighed only 0.1 gram.
Hunt was particularly influential in the field of underwater acoustics. Extensive development of this field was due to the U.S. Navy’s projects to develop sonar. (The acronym, originally derived from “sonic azimuth and range,” is attributed to Hunt.)During World War I, at the U.S. Navy’s laboratory in New London, Connecticut, G. W. Pierce had made an important beginning in developing sonar devices. Hunt was named director of the Harvard Underwater Sound Laboratory (HUSL), established during World War II for research related to undersea warfare. At its peak the HUSL included 450 people, and Hunt was actively involved in all its projects. Central developments at the HUSL were the prototype of scanning sonar and the acoustically guided torpedo. The HUSL closed after the war, but Hunt remained in touch with the U.S. Navy.
In 1950 Hunt proposed that entire oceans be scanned with low-frequency sonar and encouraged the organization of the Navy’s Artemis underwater surveillance project. His final project, which he called sic transit sonitus, was to develop a technique for processing the sound signals received by a monitor to allow an “after-the-fact” detection of a moving source (a propeller-driven ship, for example). With this technique, which Hunt first described in 1965, a sequence of averaged intensity readings is analyzed statistically to discriminate between a moving source and a random fluctuation. By 1972 Hunt was able to detect, with a probability of 90 percent, a source which had a signal-to-noise-level difference no higher than-10.6 dB, with an extremely low false alarm rate.
Hunt’s writing style was conversational and lucid, and he produced effective review articles. He had planned to write a textbook on physical acoustics but instead published the monograph Electroacoustics (1954). It contains a long historical chapter extensively based on Patent Office publications. He also left a manuscript, Origins in Acoustics, part of which, covering the period from antiquity through the seventeenth century, was published in 1978. Hunt wrote some four dozen research papers and technical reports and held about a dozen patents. Thirty-eight students received their doctorates under his direction.
In 1932 Hunt married Katharine Buckingham, a graduate of M.I.T. in architecture; they had one son, Thomas Kintzing, born in 1937. In 1925 Hunt had made a 16, 000-mile tour of the West in a Model T Ford, and he continued to pursue automobile touring with his family. He received many honors, including an honorary Sc.D. from Harvard in 1945, the Presidential Medal of Merit in 1947. the U.S. Navy’s Distinguished Public Service Medal in 1970. and medals and awards of the Acoustical Society of America and of the Audio Engineering Society. An oceanographic research ship was named for him in 1965. He died of a heart attack while atttending a convention of the Acoustical Society of America.
1. Original Works. An extensive list of Hunt’s publications, technical reports, talks, and patents is in Harry A.Schenck, Journal of the Acoustical Society of America. 57 (1975), 1255–1257. The majority of his papers appeared in Journal of the Acoustical Society of America Journal of the Audio Engineering Society, and Review of Scientific Instruments. A number of his papers are reprinted in H. E. Roys. ed., Disc Recording and Reproduction (Stroudsburg, Pa., 1978). There is a collection of Hunt’s papers and technical reports in the Hunt Reading Room of the McKay Library at Harvard University. An interview of the Niels Bohr Library at the Center for the History of Physics. American Institute of Physics.
Hunt’s publications include “On Frequency Modulated Signals in Reverberation Measurements.” in Journal of the Acoustical Society of America. 5 (1933), 127–138; “A Direct-Reading Frequency Meter Suitable for High Speed Recording.” in Review of Scientific Instruments, 6 (1935). 43–46; “HPA: A Radical Departure in Phonograph Pick-up Design,” in Electronics, 11 (March 1938), 9–12, with J. A. Pierce: “On Distortion in Sound Reproduction from Phonograph Records,” in Journal of the Acoustical Society of America 10 (1938). 14–28. with J.A. Pierce; “Analysis of Sound Decay in Rectangular Rooms.” ibid., 11 (1938), 80–94. with L.L. Beranek and D. Y. Maa; Electroacoustics: The Analysis of Transduction. and Its Historical Background (Cambridge, Mass., 1954): “Propagation of Sound in Fluids,” in American Institute of Physics Handbook (New York, 1957, 1963, 1972), see 3c: “Electroacoustics and Transducers.” in Journal of the Acoustical Society of America. 30 (1958), 375–377: “The Rational Design of Phonograph Pickups,” in Journal of the Audio Engineering Society. 10 (1962), 274–289: “The Past Twenty Years in Underwater Acoustics: Introductory Retrospection.” in Journal of the Acoustical Society of America. 51 (1972), 992–993: “Signal Rate Processing for Transit Detection,” ibid., 1164–1185; and Origins in Acoustics, Robert E. Apfel, ed. (New Haven, 1978).
II. Secondary Literature, There are accounts of Hunt by John V Bouyoucos, “Pioneers of Underwater Acoustics Medal. 1965: Frederick V Hunt,” in Journal of the Acoustical Society of America, 39 (1966). 765– 769; and by Laurence Batchelder, “Frederick V. Hunt,” ibid., 52 (1972). 52–54. The Hunt memorial issue, ibid., 57, no. 6, pt. 1 (1975), 1239–1401. includes articles about Hunt and his work by colleagues and students. The collection Epistolae pro Frederick V Hunt (n.p., n.d), written in connection with the award of the Underwater Acoustics Medal of the Acoustical Society, describes Hunt’s role at the HUSL. The work done at the HUSL is described in the Summary Technical Reports of Division 6, National Defense Research Committee (declassified 1960).