為何劇院要搞個中央聲道？

https://en.wikipedia.org/wiki/Surround_sound

The function of the center channel is to anchor the signal so that any central panned images do not shift when a listener is moving or is sitting away from the sweet spot.[27] The center channel also prevents any timbral modifications from occurring, which is typical for 2-channel stereo, due to phase differences at the two ears of a listener.[24] The centre channel is especially used in films and television, with dialogue primarily feeding the center channel.[25] The function of the center channel can either be of a monophonic nature (as with dialogue) or it can be used in combination with the left and right channels for true three-channel stereo.

若是人的對話都用中央聲道，那聽來對話就永遠都只在正中，不會偏左、偏右，但螢幕上的人就明明一個在左邊、一個在右邊，未免太呆？
若搞成左、中、右構成立體聲，喂，這不是照樣會出現三隻喇叭的相位差導致的音色變化？竊以為這觀點根本就不通。

就實務而言，我猜啊...搞出個中央聲道只是為了用低價達成效果！中央聲道根本就可以用左
右聲道取代，但如果喇叭實在太爛，例如常見的那種瘦高的小小喇叭，聲音薄弱，左右二隻的聲音還是虛軟無力，多個中央還是好一些。
訂這些標準的人思考的是大市場，針對多數人，而不是那種砸大錢買好音響的人。
如果你的喇叭不差，我不認為有必要加啥中央聲道，特別是已經有好雙聲道功率擴大機，多個中央聲道還得多一隻mono擴大機。