Stefan Kudelski was born in Poland and educated in Switzerland, first at the Federal Institute of Technology and later at the Polytechnic College of Lausanne University. As a student he developed and patented several innovative electronic devices. Among his inventions was a self-contained portable audio recorder, the first ever of its kind. Named Nagra, it allowed precise synchronization of audio tape with film, providing filmmakers with studio sound quality during on-location filming.

Kudelski was awarded a Scientific or Technical award in 1965 and again in 1977 for the development and improvements of the Nagra production sound recorder. In 1978 he received the Oscar "for the continuing research, design and development of the Nagra Production Sound Recorder for Motion Pictures."