Journal Article
A Unified 4-4-4, 4-3-4, 4-2-4 SQ--Compatible System of Recording and FM Broadcasting (USQ-)
Journal of the Audio Engineering Society · Volume 27 · Issue 11 · pp. 866–880 · November 1979
Abstract
The unified SQ surround-sound recording and broadcasting system (USQ) is a combination of technologies with the objective of spanning the present and the future requirements of the art of surround-sound reproduction. The present-day 4-2-4 SQ matrix system has been found by the FCC Laboratories (Project 2710-1) to surpass in quadraphonic listening all other matrix systems tested, and to be preferred by the listeners to the 4-channel master tape (summed pairwise) and to all other matrix codes for stereophonic and monophonic capability. Therefore if commercial demand were to arise for higher order surround-sound systems, SQ would be the matrix of choice for the basebands of future 4-2.5-4, 4-3-4, or 4-4-4 FM broadcast transmitters. Orderly means for assembling this hierarchy are described. Projecting other possibilities, it is shown that (1) a modified-with-logic 4-3-4 system offers potential advantages; (2) a "diamond" 4-3-4 decoding configuration in combination with the square or rectangular loudspeaker arrangement may lead to 4-3-6 or 4-3-8 surround-sound loudspeaker arrays with superior hemispheric; (3) SQ quadraphonic synthesis is capable of converting the existing libraries of stereo records to the surround-sound reproduction mode; (4) applications of SQ-coded signals to "Kunstkopfstereophonie" or "dummy-head listening" (J. Audio Eng. Soc., vol. 24, p. 387, 1976 June) offers a further intriguing possibility. And, not to slight those who by choice or necessity require the use of spatial (coincident, intensity) microphone systems, it is shown that the SQ Ghent microphone system (J. Audio Eng. Soc., vol. 26, pp. 2-11, 1978 Jan./Feb.) can be modified by addition of a T function so as to operate successfully in either the Ø-2-4 or the Ø-3-4 modes compatibly with all the SQ decoder configurations.
