microphone 5 sensor converting an acoustical signal into an electrical signal y t at output 9 which is supplied to the non inverting input of an amplifier 51 the transfer behavior of transducer system 1 is represented by eq 1 the input signal x t is also supplied via input 13 to a model 11 the model 11 describes the linear and nonlinear transfer behavior of transducer system 1 and generates an output signal y u2032 t at output 15 which is supplied to the inverting input of the amplifier 51 the nonlinear eq 8 describes the transfer behavior of the model 11 whereas the product of the linear parameter p l and linear gradient vector g l t is realized by using an fir filter the nonlinear term p n g n t is realized by using linear filter multiplier adder and scaling elements according to eqs 6 7 and 9 the error signal e t generated at output 49 of the amplifier 51 according eq 11 is supplied to input 35 of the nonlinear parameter estimator 23 and to input 31 of a linear parameter estimator 21 according to prior art designs both parameter estimators 21 and 23 minimize the error signal e t using.