Application of laser vibrometer for the study of loudspeaker dynamics

This paper presents an experimental and numerical study of vibrations of loudspeakers. The experimental part consisted of measuring vibrational responses of cones of the loudspeakers to the sine sweep excitation signal. Acquisition was performed by means of a laser vibrometer. The numerical analysis employed finite element simulations of the cone and suspensions, based on estimation of viscoelastic properties for loudspeaker components. Having acquired accelerations of hundreds of points on the radiating surface, the radiated sound pressure level at one-meter distance has been computed. Confronting SPLs obtained from the two approaches the authors attempted to match the numerical model with the experiment. The matching was confirmed by the comparison between the simulated and measured operational deflection shapes.