In one aspect the present subject matter is directed to a system for suppressing acoustic noise within a combustion section of a gas turbine. The system includes at least one static structure disposed forward of a combustion chamber defined within the combustion section. The static structure at least partially defines a diffuser cavity upstream of the combustion chamber. A baffle plate is coupled to the static structure. The baffle plate and the static structure at least partially define an air plenum within the combustion section forward of the combustion chamber. The baffle plate includes an aperture that provides for fluid communication between the diffuser cavity and the air plenum. The at least one static structure and the baffle plate define a Helmholtz resonator within the combustion section.