Sound scattering observations in deep water are reported for the frequency range from 2 to 20 kc. An explosive sound source was employed to give a sound having high acoustic pressures throughout the frequency range. The receiver was directed vertically downward in the water; the recorder allowed simultaneous recording over several frequency bands....
Hersey, J. B., H. R. Johnson, and L. C. Davis. 1952. "Recent findings about the deep scattering layer." Journal of Marine Research 11, (1). https://elischolar.library.yale.edu/journal_of_marine_research/754