A vibration absorber assembly including a disc shaped housing having a central rotational axis and a plurality of radially elongated cavities, and a plurality of movable masses, each movable mass being housed in, and movable within, one of the plurality of radially elongated cavities. The plurality of movable masses are movable in the plurality of radially elongated cavities to absorb torsional vibration, and/or alter moment of inertia of the vibration absorber assembly.