A professional who tests and adjusts optical, electrical, and audio-frequency equipment used to transmit, record, and reproduce sounds on motion picture set. Responsibilities include:

• Inspects sound circuit patch cords to ensure flow of current from sound stage to recording equipment.
• Tests sound circuits and equipment, such as light valves, galvanometers, microphones, and magnetic recording heads to verify standard operating condition; using portable testing instruments.
• Replaces defective components and wiring and adjusts equipment to correct defects, using handtools.