Sel-Sync
Encyclopedia
Sel-Sync or Selective Synchronous recording is the process of selectively using some record heads as play back heads so that new signals can be recorded on other tracks in perfect sync with the existing tracks. Sel-sync recording dramatically changed the recording process allowing overdubbing
of individual recorded tracks.
Sel-sync along with the multi-track head was invented by Ross Snyder at Ampex
in 1955. Three problems had to be solved: mechanical alignment, switching of the record track to playback mode and multitrack erase head. The hard problem was the switching of a track between record and playback mode. Prior to sel-sync record heads were directly wired to the record electronics and playback heads were directly wired to the playback electronics. Also the designs of the two heads were very different. The problem of switching very low-level/high-impedance circuitry without introducing hum or noise
had to be solved. Mort Fujii in the Ampex special projects lab was responsible for the actual design.
Ampex did not patent sel-sync because Ross Snyder did not think it would be of interest to more than a few musicians and an Ampex lawyer said the idea was obvious. Ampex only trademarked the name
D-2 (video)
was the first digital recording
video tape format to offer Sel-Sync "read before write" (an Ampex term) also known as "preread" on Sony
magnetic tape
recorders. Read before write allowed simultaneous playback and recording on the same VCR.
Overdubbing
Overdubbing is a technique used by recording studios to add a supplementary recorded sound to a previously recorded performance....
of individual recorded tracks.
Sel-sync along with the multi-track head was invented by Ross Snyder at Ampex
Ampex
Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence...
in 1955. Three problems had to be solved: mechanical alignment, switching of the record track to playback mode and multitrack erase head. The hard problem was the switching of a track between record and playback mode. Prior to sel-sync record heads were directly wired to the record electronics and playback heads were directly wired to the playback electronics. Also the designs of the two heads were very different. The problem of switching very low-level/high-impedance circuitry without introducing hum or noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
had to be solved. Mort Fujii in the Ampex special projects lab was responsible for the actual design.
Ampex did not patent sel-sync because Ross Snyder did not think it would be of interest to more than a few musicians and an Ampex lawyer said the idea was obvious. Ampex only trademarked the name
D-2 (video)
D-2 (video)
D-2 is a professional digital recording videocassette format created by Ampex and other manufacturers through a standards group of the Society of Motion Picture and Television Engineers and introduced at the 1988 NAB convention as a lower-cost alternative to the D-1 format...
was the first digital recording
Digital recording
In digital recording, digital audio and digital video is directly recorded to a storage device as a stream of discrete numbers, representing the changes in air pressure for audio and chroma and luminance values for video through time, thus making an abstract template for the original sound or...
video tape format to offer Sel-Sync "read before write" (an Ampex term) also known as "preread" on Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
recorders. Read before write allowed simultaneous playback and recording on the same VCR.