Audio and speakers
Center channel
The speaker placed directly below or behind the screen that carries most dialogue and anchors sound to the picture.
The center channel is the front speaker on the screen's centerline. In a typical film mix it carries the majority of dialogue along with effects tied to the middle of the frame, which makes it the most heavily used speaker in the system.
Because intelligibility depends on it, the center is the last place to economize. A speaker smaller or tonally different from the left and right makes voices boxy and pulls them away from the actors, especially for off-center seats.
Aim the center at ear height as closely as possible, with no more than about 15 degrees of vertical tilt if it must sit below the screen. Horizontal woofer-tweeter-woofer designs beam at off-axis seats; a three-way with a vertical midrange and tweeter fixes this.