Analog Circuit Model for Loudspeakers including Eddy Current Behavior and Suitable for Time Domain Simulation

This paper presents two analog circuit models for the blocked electrical impedance for a moving coil loudspeaker. The first includes an exact model of the effects of eddy currents as derived by Vanderkooy. The model is implemented using a continued fraction expansion which allows an implementation using conventional electrical circuit components. An alternative circuit suggested by Leach uses fewer components and can model not only purely semi-inductive behavior, but also other frequency variations that are are sometimes observed. Because these eddy current models do not use frequency dependent components, they can be used in time domain simulations of loudspeaker behavior that are capable of modeling mechanical and magnetic nonlinearities.