A rotatable sound attenuation device is provided comprising a central portion rotatable about a first axis, a radial portion extending outwardly from the central portion and a chamber having a closed first end and a second end opening radially outwardly of the radial portion and defining a second axis therein having a radial component thereto. A piston is disposed within the chamber and is moveable to a location along the second axis in response to a centrifugal force imparted on the piston by rotation of the central portion and the radial portion about the first axis. A biasing member operates to limit movement of the piston along the second axis. A quarter wave chamber is defined by the second, open end of the chamber and the piston and has a sound attenuating length defined by the location of the piston along the second axis of the chamber.

 
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