According to embodiments described herein, there are provided methods and apparatus for providing a driving signal to a transducer, wherein the driving signal is output by an amplifier. A method comprises receiving an indication of a voltage and a current of the driving signal; based on an electrical model of the transducer and the voltage and the current of the driving signal, estimating an estimated electrical response of the transducer representative of movement of a mass in the transducer; comparing the estimated electrical response to a desired electrical response; and controlling the driving signal based on the comparison.