Analogies are often used in electronics, mechanics and acoustics, but also in other areas of engineering, such as hydraulics, to describe a system using models derived from another physically different system. Their use is particularly useful in the study of mixed systems, i.e. made up of components of a different nature; it is therefore easy to understand how useful they can be when applied to loudspeakers: complex systems that transform an electrical signal first into mechanical force and then into acoustic pressure.
For an analogy to work it is necessary that the equations underlying the physical phenomena it describes are formally similar. A very intuitive example is represented by the similarity between Ohm’s law and the equation that relates the force applied to a body with its speed and the mechanical resistance (friction) it opposes to movement: