A discrete Fourier transform (DFT) of a position error signal (PES) of a read/write head controlled by a currently-used controller is determined. A plurality of predicted PES spectra are determined based on the DFT of the PES and a plurality of sensitivity functions associated with a plurality of controllers. One of the plurality of controllers is selected based on respective deviation metrics of the plurality of PES spectra. Servo control of the read/write head changes to use the selected controller.