An acoustic damper includes an upstream wall with an inlet aperture and a downstream wall with an outlet aperture. The acoustic damper includes a first resonator that is supported by at least one of the upstream wall and the downstream wall. The acoustic damper also includes a second resonator that is supported by at least one of the upstream wall and the downstream wall. The first resonator and the second resonator are arranged in-parallel. Also, the first resonator and the second resonator are configured to cooperatively attenuate acoustic energy associated with a fluid flowing from the inlet aperture to the outlet aperture.