“…Considering loudspeakers with enclosure, e.g., a closed box, in addition to the two aforementioned subcircuits, the low-frequency electrical equivalent often also includes a third subcircuit that is coupled with the mechanical one and is characterized by acoustical parameters depending on the geometric properties of the enclosure [23,Chapter 16], [24,Chapter 7]. Nonlinear extensions of the Thiele-Small model presented in [2] are still considered the most effective compromise between accuracy and efficiency and have been employed in many recent publications on the digital modeling of acoustic transducers [28,29,30,31,32,33,27,14].…”