A shroud for an air moving device includes a shroud body configured to at least partially surround one or more blades. The shroud body defines an annular cavity and an annular opening. The annular opening faces the one or more blades. The shroud also includes a Helmholtz resonator defined by the annular cavity and the annular opening. The Helmholtz resonator is configured to reflect sound generated by the one or more blades out of the shroud body.