Abstract Two adaptive feedforward control structures based on the filtered-x LMS algorithm have been developed for the active control of broadband vibration in structures. In the first control structure, the conventional filtered-x LMS control configuration is modified such that the transfer function between the control input and the error output is represented by an infinite impulse response (IIR) filter. An IIR filter will most efficiently model the resonances and antiresonances which are characteristic of a structure, but they introduce stability requirements that must be satisfied. In order to remove these stability problems, the equation error control configuration is developed by first filtering the error signal by the system poles before minimizing it. The control signal is obtained in both configurations by filtering the reference signal through an adaptive finite impulse filter (FIR). Both control configurations are experimentally investigated on a simply supported beam, and power reductions of up to 20 dB are observed.