On the physical origin of the electro-mechano-acoustical analogy

The electro-mechano-acoustical (EMA) analogy, introduced in the early 1900s, allows for the modeling of mechanical, acoustical, and EMA devices and systems using schematics of basic electrical elements, making possible the application of the well-established electrical network theory for studying, designing, and characterizing complex systems. By means of this elegant modeling, the behavior of intrinsically heterogeneous devices, such as microphones and loudspeaker drivers and systems, can be explained in each of the three domains and the mutual interactions between the electrical, mechanical, and acoustical parts can be precisely predicted. However, an open issue remains still unsolved: in all publications and textbooks, the EMA analogy has been always introduced only from the formal similarity of the equations describing the physical laws that regulate the basic EMA elements and a lack of insight into its physical fundamentals can be remarked. In this paper, an investigation on the existence of physical origins of the correspondences and similarities between the quantities and the laws describing the elements of electrical, mechanical, and acoustical domains is proposed and discussed. Historical research on the birth of EMA analogy theory with the fundamental contributions on its development given by the scientists and engineers is presented as well.