Center channel
Encyclopedia
Center channel refers to an audio
channel common to many surround sound
formats. It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program. The speaker
(s) connected to the center channel are placed in the center of and behind the perforated projection screen, to give the effect that sounds from the center channel are coming from the screen. In many home surround sound
units, the center channel is positioned above or below the video screen.
In the post-production
process of filmmaking
and video production
sound editing, dialogue can be mapped to other speakers when story action and direction require it, such as when the person talking is off-screen, but it is rare that there is vocal content that is completely absent from the center channel.
In material without accompanying visuals (e.g. music), the center channel simply reproduces sound intended to come from immediately in front of the listener, which usually includes the lead vocals, which are rarely panned hard left or right.
The center channel also anchors the sound field, eliminating phantom images such as those that plagued quadraphonic sound if the speakers were not precisely placed.
The center channel eliminates the need of creating a phantom center
with left and right stereo speakers. The center channel provides image stabling effects and is considered the most important channel for film production.
-1941) have always included one. Post-war stereo sound in theaters initially came from separate magnetic film reproducers synchronised to the picture, but in the 1950s systems using magnetic stripes on the film itself came into use. Cinemascope
used four such tracks (left, center, right and surround), and the subsequent Todd-AO 70mm system used six (left, left-center, center, right-center and right, plus a single surround channel). Unfortunately these magnetic systems were not only very expensive, but were also unreliable and so were little used, the industry preferring to stay with the tried, tested (and cheap) mono optical track.
Dolby Stereo
was introduced by Dolby Laboratories
in 1975. It divided the existing soundtrack area of a 35mm film print into two, allowing a two-channel recording. Each of these two channels used Dolby A type noise reduction (later replaced by Dolby SR type). In addition a matrix, similar in principle to those used for the existing matrix-type quadraphonic systems, allowed the audio for left, center and right speakers, plus a single surround channel to be carried by the two tracks. Thus Dolby Stereo provided a similar stereo performance to that previously only available in the cinema by the magnetic tracks on 4-track Cinemascope or 6-track Todd-AO (70mm) formats, but at far lower cost.
Audio frequency
An audio frequency or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human...
channel common to many surround sound
Surround sound
Surround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and...
formats. It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program. The speaker
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
(s) connected to the center channel are placed in the center of and behind the perforated projection screen, to give the effect that sounds from the center channel are coming from the screen. In many home surround sound
Home theater in a box
A "home theater in a box" is an integrated home theater package which "bundles" together a combination DVD player/ multi-channel amplifier , speaker wires, connection cables, a remote control, a set of five or more surround sound speakers and a low-frequency...
units, the center channel is positioned above or below the video screen.
In the post-production
Post-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
process of filmmaking
Filmmaking
Filmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
and video production
Video production
Video production is videography, the process of capturing moving images on electronic media even streaming media. The term includes methods of production and post-production...
sound editing, dialogue can be mapped to other speakers when story action and direction require it, such as when the person talking is off-screen, but it is rare that there is vocal content that is completely absent from the center channel.
In material without accompanying visuals (e.g. music), the center channel simply reproduces sound intended to come from immediately in front of the listener, which usually includes the lead vocals, which are rarely panned hard left or right.
The center channel also anchors the sound field, eliminating phantom images such as those that plagued quadraphonic sound if the speakers were not precisely placed.
The center channel eliminates the need of creating a phantom center
Phantom center
Phantom center refers to the way human ears detect the location of a sound; straight ahead, above, or behind the head. Since humans have one ear on each side of the head, sound in aforementioned locations creates an equal sensation in each ear. Thus, based only on hearing, the sound can be...
with left and right stereo speakers. The center channel provides image stabling effects and is considered the most important channel for film production.
History
The need for a center speaker to locate screen-centered sounds has been recognised since the Bell labs experiments in stereo sound from the 1930s, and multi-channel cinema sound systems, starting with the first commercial stereophonic film (FantasiaFantasia (film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. The third feature in the Walt Disney Animated Classics series, the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are...
-1941) have always included one. Post-war stereo sound in theaters initially came from separate magnetic film reproducers synchronised to the picture, but in the 1950s systems using magnetic stripes on the film itself came into use. Cinemascope
CinemaScope
CinemaScope was an anamorphic lens series used for shooting wide screen movies from 1953 to 1967. Its creation in 1953, by the president of 20th Century-Fox, marked the beginning of the modern anamorphic format in both principal photography and movie projection.The anamorphic lenses theoretically...
used four such tracks (left, center, right and surround), and the subsequent Todd-AO 70mm system used six (left, left-center, center, right-center and right, plus a single surround channel). Unfortunately these magnetic systems were not only very expensive, but were also unreliable and so were little used, the industry preferring to stay with the tried, tested (and cheap) mono optical track.
Dolby Stereo
Dolby Stereo
Dolby Stereo, is the trade mark that Dolby Laboratories used for the various analogue stereo cinema sound formats that they produced.Two basic systems used this name. The first was the 'Dolby SVA' system used with optical soundtracks on 35mm film...
was introduced by Dolby Laboratories
Dolby Laboratories
Dolby Laboratories, Inc. , often shortened to Dolby Labs, is an American company specializing in audio noise reduction and audio encoding/compression.-History:...
in 1975. It divided the existing soundtrack area of a 35mm film print into two, allowing a two-channel recording. Each of these two channels used Dolby A type noise reduction (later replaced by Dolby SR type). In addition a matrix, similar in principle to those used for the existing matrix-type quadraphonic systems, allowed the audio for left, center and right speakers, plus a single surround channel to be carried by the two tracks. Thus Dolby Stereo provided a similar stereo performance to that previously only available in the cinema by the magnetic tracks on 4-track Cinemascope or 6-track Todd-AO (70mm) formats, but at far lower cost.