An inverse method for estimating the electromechanical parameters of moving-coil loudspeakers

Abstract

This article presents an inverse method for estimating the electromechanical parameters of a moving-coil loudspeaker with or without the eddy current and suspension creep effects. With known voice-coil displacement, voice-coil current, and stimulus signal as inputs, four calculation procedures for the direct problem, adjoint problem, sensitivity problem, and conjugate gradient method are involved in inversely solving the unknown electromechanical parameters. The proposed method features high efficiency in solving the direct problem through a hybrid spline difference method. It requires a small number of iterations for the computational algorithm, while offering excellent accuracy in parameter estimations. Analysis results demonstrate small differences between the estimated and measured electromechanical parameters under a variety of stimulus signals, excitation times, and initial guesses. The results are also confirmed by experimental measurements. These results indicate that the proposed method has a strong potential for estimating the electromechanical parameters of moving-coil loudspeakers.

Compensating the distortion of micro-speakers in a closed box with consideration of nonlinear mechanical resistance

“…7 Several methods have been proposed to estimate the loudspeaker parameters by measuring the impedance curve of loudspeakers. 2,8,9 System identification has also been used to estimate the nonlinear parameters by measuring the input voltage and voice-coil current. 7,10,11 Most loudspeaker nonlinearities are related directly to the geometry and the material properties of the motor, suspension, cone and enclosure.…”