ABSTRACT
The system premiered with the movie White Christmas, in 1954, as part of Paramount’s VistaVision, horizontal 35mm widescreen format. Perspecta Sound employed a single, conventional monophonic sound-track, onto which were encoded subaudible control signals. Tones of 30, 35, and 40 Hz were detected by an integrator unit connected to the projector’s sound head and used to turn up the gain on center, left-, and right-hand speaker channels. Although this did not provide true stereo, it did create directional effects, with the additional advantage that mixing for Perspecta was considerably quicker than mixing for a CinemaScope magnetic soundtrack, because it only required that the sound to be panned between the three channels to follow the action on screen.
