A valve assembly comprising a rotary closure element which defines an axis of rotation and is selectively movable between a fully open position and a fully closed position. Mounted to and movable with the rotary closure element is an impedance assembly. The impedance assembly defines an inflow end and an outflow end, and comprises a plurality of fluid passageways of varying noise attenuating capability which extend from the inflow end to the outflow end. Also partially defined by the impedance assembly is a flow opening which extends from the inflow end to the outflow end.