A boom operator is an assistant of the production sound mixer. The principal responsibility of the boom operator is microphone placement, sometimes using a "fishpole" with a microphone attached to the end and sometimes, when the situation permits, using a "boom" (most often a "fisher boom") which is a special piece of equipment that the operator stands on and that allows precise control of the microphone at a much greater distance away from the actors. He or she will also place wireless microphones on actors when it is necessary.
References
The Boom Operator is the name of the host of the weekly radio program The Drive-in Speakerbox on KXUA.
