A resonating device for attenuating sound waves that are generated by a pneumatic surgical instrument is disclosed. The resonating device includes a manifold having a duct for accommodating a flow of fluid from the instrument. A plurality of canisters extend from the manifold for attenuating sound waves produced by the instrument. A neck extends into each canister and is in fluid communication with the duct and the canister. The canisters are mounted to and extend from the manifold in series. The canisters attenuate the sound waves in order from the highest frequency to the lowest frequency, thereby efficiently attenuating the sound waves.