Before revision: 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 (Fantasia-1941) have always included one.
After revision: History The need for a center speaker to locate screen-centered sounds has been recognized since the Bell Labs experiments in stereo sound from the 1930s, and multi-channel cinema sound systems, starting with the first commercial stereophonic film (Fantasia-1941) have always included one.