Double-system recording is a form of sound recording used in

motion picture A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, since ...

production whereby the sound for a scene is recorded on a tape machine that is separate from the camera or picture-recording apparatus. Double-system recording is the standard procedure on motion pictures that are originally photographed on

film A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, sinc ...

. Recording sound-on-film directly at the time of photography has several technical limitations, and no professional motion picture camera supports this option, so all production sound is recorded on a separate recorder. This procedure requires that both camera and sound recorder share a very accurate time reference, and that the speed of the camera and sound recorders be carefully governed. Originally this was done with an electro-mechanical interlock between the camera and recorder, necessitating a physical link, a cable, between recorder and camera. As quartz-based timers came into common use, film cameras and sound recorders adopted these, and these were accurate enough to remove the need for an interlock cable. Double-system recording requires that sound and picture be manually synchronized at the start of every "take" or camera run. This task was performed by the clapper slate. A clap sound on the recording is matched to the closed clapper image on the printed film, and thus the two recordings can be realigned into sync. Before magnetic recording, a double-system sound recorder was generally a phonograph lathe. Once magnetic recording became viable, a succession of magnetic sound recorders, culminating in the

Nagra Nagra is a brand of portable audio recorders produced from 1951 in Switzerland. Beginning in 1997 a range of high-end equipment aimed at the audiophile community was introduced, and Nagra expanded the company's product lines into new markets. O ...

, were the standard. As of 2007, most double-system production sound is recorded with

hard disk drive A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, pla ...

-based digital recorders, with a DAT backup. When the apparatus recording sound and image are the same, as in a

video tape recorder A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio signal, audio material from magnetic tape. The early VTRs were open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. ...

, sound is recorded directly onto the picture medium, and this procedure is called ' single-system recording'. On feature films that are photographed on

high-definition video High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines ( ...

, audio is often recorded on the video recorder and also on secondary recorder.

References

soundonsound.com
A Practical Guide To Working With Pictures, Part 3,Tips & Tricks, Published August 2000.
thefreedictionary.com sepmagyoutube.com
Magna Tech 10036-3 Film Sound Follower Recorder Player.
Sondor web sitePost Magazine Arri partners with Sondor, September 11, 2010Magna Tech 10036-3 Film Sound Follower Recorder PlayerFilm into video: a guide to merging the technologies
by
Nagra websiteNagra IIC tape recorder held at the British LibraryHistory of Nagra recorders
Stuart Blake Jones, Richard H. Kallenberger, George D. Cvjetnicanin

{{Filmmaking Film production Film and video technology Film editing

See also

References