User:B137/Center channel

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 dialog of the program. The speaker(s) connected to the center channel are usually placed in the center of the screen, or behind it, if possible, to give the effect that the talking is coming from the screen, and to keep it out of the other channels, where it would not sound right. In many home surround sound units, the center channel has two loudspeakers, is a bar, and is higher powered than the other speakers, not including the subwoofer, as it is usually taxed with the entire speech or lyrical portion of the program.

Exeptions: The dialog may not only be mapped to the center channel, such as when the source of the voice is off-screen, but it is rare that there is vocal content that is not at all on the center channel. See the center focus section below.

History

 * See also: Dolby Pro Logic

Dolby Stereo (1975) was the first surround format to use a center channel. This format was for cinema use. It's other two channels were a front left and a front right.

Dolby Pro Logic (1987) was the first major surround sound format for home use to use a center channel. It's other three channels were a front left and right, and a rear, mono channel which was matrixed from the front channels.

Center focus
Many home theater units have a "center focus" option which provides options for the dialog reproduction, as wll as the overall content mapped to the center and front channels. Common setting include modes that allow strictly dialouge to be mapped to the center channel (to the best ability of the decoder), modes that emphasize the vocals for clear dialog, and modes that mix the center and front channels, mapping some vocals to the front channels, and some non-vocal audio content to be mapped to the center channel.