Sansui's QS encoding method was one of the two most popular quadraphonic matrix-encoding techniques; the other was SQ. Unlike SQ, which emphasized left-right separation and compatibility with stereo, QS attempted to provide equivalent channel separation in all directions. That is, left front to right front channel separation was about the same as left front to left back. Early QS decoders provided separation that was nearly imperceptible. However, by the mid-'70s, Sansui's Vario-Matrix decoders produced separation in all directions exceeding 20 db, and press releases from Sansui claimed they had developed technology which pushed separation to over 40 db.
Although SQ emphasized its compatibility with stereo, initially most SQ recordings came out as special versions, separate from the standard stereo versions of the same releases. In contrast, at least in the U.S., almost all recordings released using the QS matrix were released only in quad; separate stereo versions rarely existed.
Playing QS recordings through an SQ or an EV decoder will provide you with a satisfying result. However, for best results, especially from recordings with direct sounds recorded in the rear channels, such as the Gershwin and Ravel Vox Boxes, you should play these recordings through a Sansui Vario-Matrix decoder.
Last updated: October 13, 2001