Talking pictures : how they are made and how to appreciate them (1937)

The Stage Is Set The present round microphone form allows the sound waves to pass smoothly around the microphone as air passes smoothly around a modern airplane wing, and distorting air bubbles are thus reduced. Perfect sound waves are spherical, just as the circles which spread out when a stone is tossed into a pool are circular. Two men control the microphone. One, the "boom man," operates the boom, moves it to follow the players as they move through a scene. The company recording engineer may be high above the set in a sound-proof booth with double glass windows put in a side of the upper part of the stage, or in a portable, equally sound-proof booth placed just off the set itself. Or he may wear head telephone receivers. In all instances his equipment is the same. His fingers are on several dials, not unlike those of a radio, which regulate the volume of sound delivered to the recording machines. His eyes watch a dial on which a needle flickers quickly, showing how much recording current the voices of the actors are generating. With his loud-speaker or headset he listens to what is being said to the microphone on the set in front of him. iVs the sound is delivered to his ears, his fingers on the dials raise or lower the volume at his trained discretion. In front of us is a strange appearing device called the "rotumbulator." This is a camera platform so constructed that in a second it can run noiselesslv to the top of a heavy eight-foot post. On its moving circular base it can move up and down and sideways. The whole structure is on rubber wheels and one man can move it noiselessly backward or forward on special aluminum [ i67]