Some Psychoacoustic Phenomena Related to Quadraphonic Reproduction

Heretofore unexplored psychoacoustic phenomena having special bearing on matrix quadraphony have been studied using centrally located observers facing a small end of a simulated rectangular living room with loudspeakers in the corners. It was observed that (1) monotonic all-pass phase-shift networks (“psi-networks”) do not perceptibly affect sound quality; (2) signals applied to the two front loudspeakers through differential quadrature filters appear to spread out and to shift towards the loudspeaker carrying the leading signal (“quadrature shift”); (3) directional cues attributable to signals from the front loudspeakers are relatively uninfluenced by lesser-magnitude similar signals applied to back loudspeakers (“front source dominance”); and (4) the perceived angular coverage of the field produced by the back loudspeakers is substantially smaller than that produced by the front loudspeakers (“back image contraction”).