Quadraphony, Spatial High Fidelity, And Compatibility

The premise of this paper is that quadraphony is essential to true high fidelity, and that a most important criterion of merit of a quadraphonic system, in addition to its directional efficacy, is compatibility with the existing monophonic and stereophonic players and broadcast transmission/reception apparatus. It is argued that, given the usual dimensional limitations of electromagnetic spectrum, or the area of recording medium, or cost, matrix quadraphony is the preferred engineering solution and that the CBS SQ¿matrix is the optimal matrix for this purpose. The unique advantages of the SQ matrix are phase integrity and total separation of front channels which transmit unaltered the concert stage sounds, and its in-quadrature coding of back channels which allows them to be "folded" optimally in the stereo mode and to be transmitted at full level in the monophonic mode, a combination not found in other matrix systems. Alternative systems are discussed and are found wanting because of relatively poor front-channel separation or phase-shifted center-front signal or excessive loss of the back-corner signals in monophonic reproduction, or all three deficiencies combined.