Pilottone
Encyclopedia
Pilottone and the related neo-pilottone are special synchronization
signals recorded by analog audio recorders designed for use in motion picture
production. Before the adoption of timecode by the motion picture industry in the late 1980s, pilottone-sync was the basis of all professional magnetic motion picture sound recording systems, whereas most amateur film formats used pre-striped magnetic coating
on the film itself for live-sound recording.
, camera operator and filmmaker at West-German Nordwestdeutscher Rundfunk
(NWDR) during the 1950s, pilottone was invented at the NWDR studio in Hamburg-Lokstedt
, West Germany by NWDR technical engineer Adalbert Lohmann and his assistant Udo Stepputat in the early 1950s for single-camera
16mm TV news gathering and documentaries. The first program featuring the use of pilottone was the documentary Musuri - Es geht aufwärts am Kongo ("Musuri: Upstream/progress at the Congo"), shot in early 1954 in Africa and first broadcasted on ARD
on March 31, 1954. The new technology required new editing suites, and Musuri camera operator Diercks turned to a small nearby 6-man workshop named Steenbeck
. The subsequent success of priorly shunned 16mm for TV program gathering facilitated by the pilotone system turned Steenbeck into a multinational corporation.
Neo-pilottone was invented in 1957 by Stefan Kudelski
with the Nagra III
tape recorder.
The new technology of pilottone was brought to international attention by its use by Richard Leacock
, former cameraman of filmmaker Robert Flaherty, in his documentary feature Primary
(1960), documenting the competing Democrat presidential nominee candidates Hubert Humphrey
and John F. Kennedy
. Diercks himself helped the spread of pilottone in the USA when he was the only Western reporter allowed to shoot in Havanna during the Bay of Pigs Invasion
in April 1961. CBS
secured the licensing rights to Diercks's material via Norddeutscher Rundfunk
(NWDR had split in 1956 into NDR and WDR), and brought it on air on May 14, 1961, ten days prior to the German broadcast of the same material. At a time when North-American TV program gathering was dominated by either Movietone
(see also Movietone News
) or magnetic pre-striping for live-sound recording, and the use of pilottone was still unheard of, according to Diercks the US TV networks were impressed with the system demonstrated by the 60-minute documentary feature.
The recorder has a double recording head, similar to a two-track recorder. Each of the two cores of the recording head records both the audio signal, and the pilot tone. The audio signal to be recorded is applied identically to both cores of the recording head, and the pilot tone sine wave is applied in a push-pull arrangement (180 degrees out-of-phase).
Unlike the recording head, the playback head has a single core. The playback head gap covers both of the tracks created by the record head. The magnetic field changes across the width of the gap are effectively added in the playback head, so the playback head reproduces the audio signal, which is the same in both tracks. But the pilot tone cancels itself in the playback head: at a point on the tape where it has a certain intensity on the upper track, it has the opposite intensity on the lower track, and so always sums to zero.
On playback, the record head is used as a push-pull playback head in order to reproduce the pilot tone. All speed variations of the camera and tape can be detected as deviations from 60/50 Hz, and compared at the time of playback with in built quartz reference oscillator. For cinematic audio, speed variations are rectified (resolved) at the time of transfer to the perforated 35mm/16mm audio tape. At that time the mains power supply frequency is also taken as reference. (The selection of the 60/50 Hz equipment depends on the power supply in the country where filming is being conducted. North America has a supply of 60 Hz whereas Europe and some Asian countries have 50 Hz.)
Normal audio tape recorders have good regulation of tape speed, but not sufficiently precise to guarantee that a playback machine will exactly match the speed of the recorder over long periods of time. Such a system would need to record exactly how much tape passes the head in such an amount of time, and would have to be accurate to a quarter inch after 800 feet or more. Pilottone provides such a system.
When the tape is played back on a pilottone-reading tape player, it needs to only resolve the pilottone signal on the tape. The player has a quartz oscillator
of its own, and when the operator hits play, the player tries to match the sine wave
of the recorded pilottone with the pilottone being generated by its own quartz crystal. When they match up, the player knows that the tape is moving across its play head exactly as fast as it was across the record head when it was originally recorded.
In such a situation where the speed of the camera and the recorder are absolutely free of any variation there remains no need for a synchronization pulse cable to run between the camera and the recorder. This has made the work of a sound man much simpler. It also give more freedom of movement to the camera at the time of motion picture filming.
Additionally the use of SMPTE time code
on source recordings simplifies finding match points in post production between picture and audio in both the film and television worlds.
Synchronization
Synchronization is timekeeping which requires the coordination of events to operate a system in unison. The familiar conductor of an orchestra serves to keep the orchestra in time....
signals recorded by analog audio recorders designed for use in motion picture
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
production. Before the adoption of timecode by the motion picture industry in the late 1980s, pilottone-sync was the basis of all professional magnetic motion picture sound recording systems, whereas most amateur film formats used pre-striped magnetic coating
Coating
Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...
on the film itself for live-sound recording.
History
According to Carsten DiercksCarsten Diercks
Carsten Diercks was a German documentary filmmaker.Diercks started his career after World War II at the radio station of the Nordwestdeutscher Rundfunk. 1952 he became cinematographer with NWDR TV station. In 1953 he participated in the first tests of pilot tone...
, camera operator and filmmaker at West-German Nordwestdeutscher Rundfunk
Nordwestdeutscher Rundfunk
Nordwestdeutscher Rundfunk was the organization responsible for public broadcasting in the German Länder of Hamburg, Lower Saxony, Schleswig-Holstein and North Rhine-Westphalia from 22 September 1945 until 31 December 1955. Until 1954, it was also responsible for broadcasting in West Berlin...
(NWDR) during the 1950s, pilottone was invented at the NWDR studio in Hamburg-Lokstedt
Hamburg
-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...
, West Germany by NWDR technical engineer Adalbert Lohmann and his assistant Udo Stepputat in the early 1950s for single-camera
Single-camera setup
The single-camera setup, or single-camera mode of production, is a method of filmmaking and video production. A single camera—either motion picture camera or professional video camera—is employed on the set and each shot to make up a scene is taken individually...
16mm TV news gathering and documentaries. The first program featuring the use of pilottone was the documentary Musuri - Es geht aufwärts am Kongo ("Musuri: Upstream/progress at the Congo"), shot in early 1954 in Africa and first broadcasted on ARD
Das Erste
Erstes Deutsches Fernsehen , marketed as Das Erste , is the principal publicly owned television channel in Germany...
on March 31, 1954. The new technology required new editing suites, and Musuri camera operator Diercks turned to a small nearby 6-man workshop named Steenbeck
Steenbeck
Steenbeck is a brand name that has become synonymous with a type of flatbed film editing suite which is usable with both 16 mm and 35 mm optical sound and magnetic sound film.The Steenbeck company was founded in 1931 by Wilhelm Steenbeck in Hamburg, Germany...
. The subsequent success of priorly shunned 16mm for TV program gathering facilitated by the pilotone system turned Steenbeck into a multinational corporation.
Neo-pilottone was invented in 1957 by Stefan Kudelski
Stefan Kudelski
Stefan Kudelski is a Polish audio engineer, famous for creating the Nagra series of professional audio recorders....
with the Nagra III
Nagra
Nagra is the trademark referring to any of the series of mostly battery-operated portable professional audio recorders produced by Kudelski SA, based in Cheseaux-sur-Lausanne, Switzerland....
tape recorder.
The new technology of pilottone was brought to international attention by its use by Richard Leacock
Richard Leacock
Richard Leacock was a British-born documentary film director and one of the pioneers of Direct Cinema and Cinéma vérité.-Early life and career:...
, former cameraman of filmmaker Robert Flaherty, in his documentary feature Primary
Primary (film)
Primary is a 1960 Direct Cinema documentary film about the 1960 Wisconsin Primary election between John F. Kennedy and Hubert Humphrey for the United States Democratic Party nomination for President of the United States....
(1960), documenting the competing Democrat presidential nominee candidates Hubert Humphrey
Hubert Humphrey
Hubert Horatio Humphrey, Jr. , served under President Lyndon B. Johnson as the 38th Vice President of the United States. Humphrey twice served as a United States Senator from Minnesota, and served as Democratic Majority Whip. He was a founder of the Minnesota Democratic-Farmer-Labor Party and...
and John F. Kennedy
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....
. Diercks himself helped the spread of pilottone in the USA when he was the only Western reporter allowed to shoot in Havanna during the Bay of Pigs Invasion
Bay of Pigs Invasion
The Bay of Pigs Invasion was an unsuccessful action by a CIA-trained force of Cuban exiles to invade southern Cuba, with support and encouragement from the US government, in an attempt to overthrow the Cuban government of Fidel Castro. The invasion was launched in April 1961, less than three months...
in April 1961. CBS
CBS
CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...
secured the licensing rights to Diercks's material via Norddeutscher Rundfunk
Norddeutscher Rundfunk
Norddeutscher Rundfunk is a public radio and television broadcaster, based in Hamburg. In addition to the city-state of Hamburg, NDR transmits for the German states of Lower Saxony, Mecklenburg-Vorpommern and Schleswig-Holstein...
(NWDR had split in 1956 into NDR and WDR), and brought it on air on May 14, 1961, ten days prior to the German broadcast of the same material. At a time when North-American TV program gathering was dominated by either Movietone
Movietone sound system
The Movietone sound system is a sound-on-film method of recording sound for motion pictures that guarantees synchronization between sound and picture. It achieves this by recording the sound as a variable-density optical track on the same strip of film that records the pictures...
(see also Movietone News
Movietone News
Movietone News is a newsreel that ran from 1928 to 1963 in the United States, and from 1929 to 1979 in the United Kingdom.-History:It is known in the U.S. as Fox Movietone News, produced cinema, sound newsreels from 1928 to 1963 in the U.S., from 1929 to 1979 in the UK , and from 1929 to 1975 in...
) or magnetic pre-striping for live-sound recording, and the use of pilottone was still unheard of, according to Diercks the US TV networks were impressed with the system demonstrated by the 60-minute documentary feature.
Technology
The synchronization is obtained when a pulse cable is connected from Motion picture camera to an audio recorder such as those made by Nagra. A camera with a Sync motor sends a 60/50 Hz signal to the recorder, which is recorded as a sine wave pilot tone.The recorder has a double recording head, similar to a two-track recorder. Each of the two cores of the recording head records both the audio signal, and the pilot tone. The audio signal to be recorded is applied identically to both cores of the recording head, and the pilot tone sine wave is applied in a push-pull arrangement (180 degrees out-of-phase).
Unlike the recording head, the playback head has a single core. The playback head gap covers both of the tracks created by the record head. The magnetic field changes across the width of the gap are effectively added in the playback head, so the playback head reproduces the audio signal, which is the same in both tracks. But the pilot tone cancels itself in the playback head: at a point on the tape where it has a certain intensity on the upper track, it has the opposite intensity on the lower track, and so always sums to zero.
On playback, the record head is used as a push-pull playback head in order to reproduce the pilot tone. All speed variations of the camera and tape can be detected as deviations from 60/50 Hz, and compared at the time of playback with in built quartz reference oscillator. For cinematic audio, speed variations are rectified (resolved) at the time of transfer to the perforated 35mm/16mm audio tape. At that time the mains power supply frequency is also taken as reference. (The selection of the 60/50 Hz equipment depends on the power supply in the country where filming is being conducted. North America has a supply of 60 Hz whereas Europe and some Asian countries have 50 Hz.)
Normal audio tape recorders have good regulation of tape speed, but not sufficiently precise to guarantee that a playback machine will exactly match the speed of the recorder over long periods of time. Such a system would need to record exactly how much tape passes the head in such an amount of time, and would have to be accurate to a quarter inch after 800 feet or more. Pilottone provides such a system.
When the tape is played back on a pilottone-reading tape player, it needs to only resolve the pilottone signal on the tape. The player has a quartz oscillator
Quartz clock
A quartz clock is a clock that uses an electronic oscillator that is regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks are at least an order of magnitude more accurate than good mechanical clocks...
of its own, and when the operator hits play, the player tries to match the sine wave
Sine wave
The sine wave or sinusoid is a mathematical function that describes a smooth repetitive oscillation. It occurs often in pure mathematics, as well as physics, signal processing, electrical engineering and many other fields...
of the recorded pilottone with the pilottone being generated by its own quartz crystal. When they match up, the player knows that the tape is moving across its play head exactly as fast as it was across the record head when it was originally recorded.
Replacement by Crystal sync
The pilottone system is now obsolete. In the film world the virtually universal use of crystal controlled motors on cameras and digital audio recorders with crystal controlled sampling frequencies assures synchronization of the time base between picture and sound.In such a situation where the speed of the camera and the recorder are absolutely free of any variation there remains no need for a synchronization pulse cable to run between the camera and the recorder. This has made the work of a sound man much simpler. It also give more freedom of movement to the camera at the time of motion picture filming.
Additionally the use of SMPTE time code
SMPTE time code
SMPTE timecode is a set of cooperating standards to label individual frames of video or film with a time code defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification...
on source recordings simplifies finding match points in post production between picture and audio in both the film and television worlds.
External links
- Interview with Carsten Diercks on the invention of pilottone (3:17 min, RealMediaRealMediaRealMedia is a proprietary multimedia container format created by RealNetworks. Its extension is ".rm". It is typically used in conjunction with RealVideo and RealAudio and is used for streaming content over the Internet....
; in German), with excerpts from Musuri - Es geht aufwärts am Kongo (1954), world's first use of pilottone