Disclosed is a flutter damper including a first plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a first fan flutter mode, the first plurality of chambers in fluid communication with a flow surface, and a second plurality of chambers configured for peak acoustical energy absorption at a frequency range that is associated with a second fan flutter mode, the second plurality of chambers in fluid communication with the flow surface, and wherein the first plurality of chambers and second plurality of chambers are disposed in a grid pattern.