Nagra-brand tape recorders were the de-facto standard sound recording systems for motion picture and single-camera television production from the 1960s 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. A Nagra recorder prominently appears in the 1981 movie Diva, which features an opera fan making bootleg tapes of his favorite opera singer; another Nagra (a Nagra III) features prominently in the 1981 John Travolta film Blow Out about a freelance sound effects engineer. The word "nagra" comes from Stefan Kudelski's mother tongue (Polish) and stands for "[it] will record".
The analogue Nagra recorders have a reputation for extreme ruggedness and reliability, essentially being the "Swiss watch" of audio tape recorders. Their cases are highly durable, and every component, from the transport rollers to the gain pots have the feel of excellent engineering. The feature that gave Nagra the edge in quality and film use was Stefan Kudelski's development of the Neo-Pilottone system, where synchronization data could be recorded on the tape in the middle of the audio track, but without crosstalk onto the program recording.
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."
Neopilot was the standard synchronization system used in filmmaking until the late 1980s, when timecode became the preferred standard. Nagra used a special, very narrow timecode track located in between the space of channel 1 and channel 2 on the stereo Nagra IV-S and T models. The advantage of timecode over Pilottone was in being able to slave the visual time code signal on a timecode slate, like the award winning Denecke model commonly used by major studios; similar slates were also manufactured by companies like Ambient of Germany and PSC of Valencia, California. By the mid-1990s, the use of analog 1/4" tape began to transition to DAT, which also used time code. By the mid-2000s, the industry trend was firmly set to non-linear recorders, such as Zaxcom's Deva and Aaton Cantar systems, along with lower-cost recorders from Sound Devices.
Nagra recorders are identified by their model number, which indicate their technological generation and features:
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 have also produced a series of miniaturised 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.
The SN range comprises the following models:
A special version of the SN using unique tape cassettes was made in cooperation with JBR Technology and widely used by US domestic intelligence agencies.
The Nagra IV-STC was the standard for film and classical music recording until the mid-1990s, when DAT recorders became reliable enough to use in the field. In response, Kudelski produced two digital recorders to compete:
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. Nagra's main business in the 2000s has diversified into digital security encrypting systems, including cable TV and satellite descrambling systems and other high-tech components, while audio occupies a smaller side of their manufacturing.
In 1997, Nagra launched the PL-P, a vacuum tube phono preamplifier, beginning a range of high-end audio equipement comprising preamplifiers, amplifiers and CD players. That range is intended for audiophile consumers (as opposed to exclusively professional equipment manufactured hitherto).
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.