Center channel

[1] 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.

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.

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 economical mono optical track.

It divided the existing soundtrack area of a 35 mm film print into two, allowing a two-channel recording.

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.