FRITZ INGERSLEV 1912-1994

BY PER V. BRÜEL

The acoustical scientific community has lost a great personality—"noise professor" Fritz Ingerslev, who died on February 5, 1994, at the age of eighty- one. The title "noise professor" characterizes Fritz Ingerslev well. He was not only a famous and dedicated professor who worked industriously with technical research projects, but he also managed to simplify for the layman difficult concepts in acoustics and especially noise. It is, to a great extent, due to the achievements of Professor Ingerslev that highly effective work is carried out in today's Europe to prevent and solve noise problems.

Professor Ingerslev was born in Aarhus, Denmark, on July 6, 1912. He received his doctorate in electrical engineering from the Technical University of Denmark in 1936. In 1945 he became head of the Acoustical Laboratory at the Academy of Technical Sciences, where he served until 1981. From 1954 to 1982 Fritz Ingerslev was both professor of building acoustics at the Technical University of Denmark and the head of the Acoustics Laboratory at the university. From 1955 to 1963 he was chairman of the Danish Acoustical Society, which he himself had founded. Professor Ingerslev was highly motivated for international cooperation. It was quite natural that he became a longtime member of the coordinating committee for the International Congress on Acoustics, which was founded in 1951. From 1974 to 1987 he was the founder and president of the International Institute of Noise Control Engineering, which has organized INTER—NOISE each year since 1972. Ingerslev was president for INTER— NOISE in 1973. He was elected a foreign associate of the U.S. National Academy of Engineering in 1982. Professor Ingerslev was the author of more than fifty technical publications.

Fritz Ingerslev's career started when Professor P. O. Pederson, who was then the headmaster of the Technical University of Denmark (Den Polytekniske Laereanstalt), decided to concentrate on research activities in acoustics and emphasize the teaching of room acoustics. In 1941 the Acoustical Laboratory was founded under the Academy of Technical Sciences and a few years later it came under his daily leadership. In 1949 Ingerslev's book on building acoustics for engineers was published, and in 1953 his Ph.D. thesis on distortion in electrodynamic loudspeakers. In 1954 Ingerslev was appointed professor of acoustics. Under his leadership, laboratory activities increased significantly as well as the interest in the teaching of acoustics. It is solely due to Ingerslev's merits and his indefatigable struggle for his profession that the Danish Technical University today has one of Europe's largest anechoic chambers for teaching and research purposes.

Ingerslev had a special interest for international standardization. From the early 1950s he was active in the International Electrotechnical Commission (IEC) Committee of Electroacoustics, where he was deeply involved with the international standards for hearing aids. Later it became his task, as the chairman of the International Standards Organization (ISO) Acoustic Committee over a period of twenty years, to coordinate the international points of view and formulate common standards for sound and especially various types of noise measurements. The contagious effects of his enthusiasm on his fellow workers in Danish industry can be seen from the high Danish influence on international standardization for acoustics. The secretariats for both IEC's and ISO's acoustic committees are administered by the Danish Standards Association.

Professor Ingerslev's expertise, combined with his incredible involvement in the struggle to protect the individual from noise pollution, made him well known. Large traffic projects—for example, expansion of Kastrup Airport in Copenhagen—were originally planned without due consideration to the serious noise problems it would cause for the nearby community. It was Ingerslev's way of dealing with these problems that made the authorities realize how serious a threat noise could be to the environment. It often required untiring efforts and a good portion of pedagogy to reconcile technical scientific results to the authorities. Because of his success, directives for noise protection are in place today.

Professor Ingerslev was deeply involved in the pioneering work for the present Danish Ministry for the Environment and was instrumental in formulating twenty years ago a farsighted environmental policy, which is used as a model in many countries today.

Fritz Ingerslev was a great initiator, who not only could inspire his coworkers and the students at the Danish Technical University, but also knew how to struggle politically for his profession. The Danish electroacoustic industry, research, and education have much to thank him for. Those who continue development of the acoustic field today are deeply indebted to Professor Ingerslev. His efforts and international reputation will be remembered for many years.