A new measurement technique is presented for the estimation of the linear parameters of the lumped transducer model. It is based on the measurement of the electrical impedance and the voice coil displacement using a laser sensor. This technique identifies the electrical and mechanical parameters directly and dispenses with a second measurement of the driver using a test enclosure or an additional mass. Problems due to leakage of the enclosure or the attachment of the mass are avoided giving accurate and reliable results. The measurement of the displacement also allows identification of the mechanical compliance versus frequency (explaining suspension creep) which is the basis for predicting the radiated sound pressure response at low frequencies precisely. The linear parameters measured at various amplitudes are compared with the results of large signal parameter identification and the need for nonlinear transducer modelling is discussed.
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