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frequency was abbreviated as f instead of ν; vectors, phasor, and other complex variables were distinguished by bold fonts). Kinsler and Frey also added stand-alone chapters on applications like loudspeaker, microphones, speech, hearing, community noise, and architectural acoustics. Most importantly, from the perspective of the NPS was a detailed chapter on underwater acoustics that included attenuation in seawater, transmission loss and the SONAR equation, refraction in a constant or piece- wise-linear sound speed gradient, bottom and surface scattering, and ambient noise.
The third (1982) and fourth (2000) editions were pro- duced by two other NPS physics faculty members, Alan B. Coppens and James V. Sanders, who are listed as coauthors. The third edition deleted some calculations (e.g., correction to frequency due to the spring’s mass in a harmonic oscillator) and expanded the underwater acoustics chapter. The fourth edition added an introduc- tion to detection and estimation theory to the underwater acoustics chapter and added two more chapters. The first new chapter, titled “Selected Nonlinear Acoustic Effects,” introduced some weak shock theory and the parametric array. The second, titled “Shock Waves and Explosions,” was a topic that was included in the acoustics curriculum at the NPS but is not a subject that was commonly taught to the larger audience of acoustics students.
Only Fluids
Several other acoustics textbooks were produced that did not follow the Lamb template because they only addressed acoustics in fluids. Two of the most influential of those textbooks include Blackstock’s textbook, Funda- mentals of Physical Acoustics (2000) that introduces the wave equation for fluids on page 2 and Pierce’s Acoustics (2019) that was first published in 1981 and introduces it on page 17. Both Pierce and Blackstock included more advancedtopics,asdidSkudrzyk(1971),Lighthill(1978), and Temkin (1981), so they were frequently used for more advanced courses.
An Alternative to the Legacy of Mid- Atlantic Theoreticians
For over sixty years, the four editions of Fundamentals of Acoustics have dominated acoustics education for stu-
dents of science and engineering between 1960 and 2020. In addition to asking why that textbook was so successful, it may be important to consider the possibility that the
perspectives and prejudices that are perpetuated in Kin- sler and Frey’s incarnation of the Lamb/Morse tradition are not optimal in an age dominated by computers. As D. A. Brown of the University of Massachusetts-Dart- mouth likes to say, “Virtually every engineering problem is [now] solved with an ‘Enter’ key,” and “Engineering without physics is faith” (email to author, April 7, 2021).
As argued in Historical Context, the sequence of acous- tics textbooks that followed The Theory of Sound in the twentieth century were written by individuals who considered themselves to be theoreticians, even though Rayleigh was a champion of both rigorous experimental investigations and structured laboratory classes. Those textbooks were written in the glow of the “golden age” of analysis. In addition to Rayleigh’s Theory of Sound and Lamb’s Hydrodynamics, Love published the first edition of A Treatise on the Mathematical Theory of Elasticity in 1893 (Love, 1927). The turn of that century was an era when the methods developed for the solution of dif- ferential equations were being successfully exploited to unify a mind-boggling number of physical problems in the mechanics of continua.
This theoretical prejudice was “baked in” by the Lamb/ Morse textbooks that include Kinser and Frey for the reasons already presented. Even though Kinsler and Frey taught in Monterey, California, their treatment reflected the mid-Atlantic perspectives that were formulated in the United Kingdom and Cambridge, Massachusetts. But start- ing in the 1950s, there was an authentically “Californian” alternative perspective that was emerging in the physics department at the University of California, Los Angeles (UCLA) that was already a leading force in architectural acoustics (Knudsen and Harris, 1950) and cinema under the direction of Knudsen and DelSasso (Shaw, 2011).
In 1948, after completing his PhD under Knudsen’s supervision and wartime research at Pennsylvania State University, University Park (Schilling, 1950), Isadore Rud- nick was hired as a junior faculty member in the physics department at UCLA, where he spent the remainder of his career (Garrett et al., 2017). In 1970, immediately after completing his Ph.D. on superfluid hydrodynam- ics (Putterman, 1974) under the supervision of the great Dutch physicist G. E. Uhlenbeck, Putterman was hired to work primarily as the theoretician for the Rudnick group. Uhlenbeck was a student of Ehrenfest, and Ehrenfest
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