Stefan Kudelski was the inventor of the first professional-quality portable tape recorder, which revolutionized Hollywood moviemaking and vastly expanded the reach of documentarians, independent filmmakers and eavesdroppers on both sides in the Cold War.
The Polish-born Mr. Kudelski was an engineering student at a Swiss university in 1951 when he patented his first portable recording device, the Nagra I, a reel-to-reel tape recorder, about the size of a shoe box and weighing 11 pounds, that produced sound as good as that of most studio recorders, which were phone-booth-size. Radio stations in Switzerland were his first customers.
The bigger breakthrough came seven years later, when Mr. Kudelski introduced a high-quality tape recorder that could synchronize sound with the frames on a reel of film. Mr. Kudelski’s 1958 recorder, [the Nagra III](
http://www.filmsoundsweden.se/backspegel/kudelski.html), weighed about 14 pounds and freed a new generation of filmmakers from the conventions and high cost of studio production.
Along with the newly developed portable 16-millimeter camera, the Nagra recorder became an essential tool for the on-location, often improvisational techniques of New Wave directors like François Truffaut and Jean-Luc Godard, and American documentarians like D. A. Pennebaker, who used the Nagra to record the 1965 Bob Dylan tour featured in his classic film “Don’t Look Back,” released in 1967.
