Nagra – the pioneer in audio recording


Nagra-brand tape recorders were the standard sound recording systems for motion picture and single-camera television production until the 1990s. Their physical appearance, with the single transport selector and large reel-to-reel tape deck are still the stereotypical image most people have of a professional tape recorder. Nagra recorders are produced by Kudelski SA, based in  Switzerland. The machines were initially designed by Polish inventor Stefan Kudelski, and his company won numerous technical awards for their precision and reliability.

The reputation of Nagra equipment is firmly established among audio professionals. Whether in the television and cinema industries or among radio journalists, Nagras are always appreciated for their sound quality and reliability. Equipment such as the Nagra 4.2 and the Nagra IV-S Time Code are seen as benchmarks in terms of sound recording for cinema productions and have been used on film sets the world over. The performance of this equipment has been recognized with three Oscars® and an Emmy® Award.

It was in 1951, that the Nagra takes a concrete form: a portable audio tape recorder with exceptional specifications, i.e. light, small, self-contained, portable and high quality. In 1952 the first customers, Radio Lausanne and Radio Geneva placed official orders for the Nagra I. Production of the Nagra II began in 1953. The Nagra II is quite sophisticated, driven by a Gramophone spring from language laboratory equipment, and with excellent subjective and audio quality. In 1958 the Nagra III sees the light of day. It was a solid-state machine employing an electric motor with closed loop servo speed control. It was a fully transistorized machine with all the modules enclosed in metal cases. It was powered by conventional “D” type batteries. Moreover, it was equipped with a true peak meter called a “Modulometer”.

Stefan Kudelski invented the “Neopilot” system, and the first Nagra III machines equipped with the system were sold in 1962. Kudelski SA defines Neopilot as follows: “Full track monophonic recorders (Nagra models III, E, IV and 4.2) use a patented system in order to control the speed of the NAGRA during playback to ensure it turns at the exact same speed as the reference (Projector / Camera / Perfo-tape machine). The frequency of the pilot signal is 50/60 Hz and is often derived from the mains. The signal is recorded as a twin track signal 180° out of phase so as to be invisible to the full track playback head. The start point is indicated by the clap of the film clapper board and the synchronization to the magnetic film is maintained using the pilot signal throughout the take.”

Nagra recorders are identified by their model number, which indicates their technological generation and features:

  • Nagra I – The very first prototype with clockwork motor and miniature tubes, appearing in 1951.
  • Nagra II – The first production model, miniature tubes equipped, clockwork motor, appearing in 1953.
  • Nagra II CI – The second generation fitted with printed circuit boards replacing chassis wiring, appearing in 1955.
  • Nagra III NP – The first Nagra usable for film work, appearing in 1962.
  • Nagra IV-L – Monaural, featuring two microphone inputs and a built in audio limiter. Introduced in 1968.
  • Nagra 4.2 – Same as the IV-L, but added powering for microphones and built-in equalizers. Introduced in 1972.
  • Nagra IV-S – Stereo Nagra, recording two-track stereo. It had dual level pots, limiters, and equalizer presets. It was introduced in 1971. Originally it was available with a pilottone crystal, and then in 1984, with timecode support. With timecode support an IV-S became a Nagra IV-STC.
  • Nagra IV-SJ – Stereo Nagra for instrumentation and logging. Pots are replaced with switches to set gain in precise steps, no limiters, and when present, the microphone inputs are for high-voltage unbalanced instrumentation mics rather than low impedance balanced with T-power and phantom.
  • NAGRA E – A simple, single-speed (7.5ips), mono recorder aimed at radio reporters was introduced in 1976.

In addition to these field recorders, Kudelski S.A. produced a studio recorder called the Nagra T-Audio, designed mainly for use in telecines for transferring dailies. All of the above machines use 1/4″ tape.

Kudelski SA has also produced a series of miniaturized reel-to-reel recorders using 1/8″ tape. These machines are referred to as SN (for Série Noire) and production was originally ordered by President Kennedy for the United States Secret Service.

Aside from its line of motion picture sound recorders, Kudelski S.A. originally produced and continues to produce high-quality recorders for electronic news gathering, radio, and music recording. The ARES-PII hand-held recorder for journalists, and the Universal digital recorder, the ARES-BB+, both introduced in 2004, are state-of-the-art digital recorders recording to compact flash PC cards. They offer USB file download and can record both linear PCM or MPEG compressed audio.

Although digital recording is now the norm for most dialog recording in motion pictures and television series, sound effects recordists still use analog Nagra tape recorders for certain kinds of background sounds, particularly explosions, gunshots, and other loud sounds of extreme dynamic range. Engineers advise that while digital recording is technically more accurate, analog tape recording still has the edge in terms of being able to handle unexpected signal overloads.


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