An air-cooled enclosure of an information handling system has a chassis that receives at least one heat-generating functional component. An air mover is positioned within the chassis to move air within the chassis to convectively cool the at least one heat-generating functional component. An acoustic resonator includes a resonator body having a cavity sized to resonate at an acoustic frequency corresponding to a selected acoustic noise frequency, such as blade passage frequency, associated with the fan. The resonator body has an opening to the cavity that is directed toward and positioned a distance from the fan to receive and attenuate acoustic noise.