The present disclosure relates to a tunable magnonic crystal device comprising a spin wave waveguide, a magnonic crystal structure in or on the spin wave waveguide, and a magneto-electric cell operably connected to the magnonic crystal structure. The magnonic crystal structure is adapted for selectively filtering a spin wave spectral component of a spin wave propagating through the spin wave waveguide so as to provide a filtered spin wave. The magneto-electric cell comprises an electrode for receiving a control voltage, and adjusting the control voltage controls a spectral parameter of the spectral component of the spin wave via an interaction, dependent on the control voltage, between the magneto-electric cell and a magnetic property of the magnonic crystal structure.