I did try QS, but I get more response using SQ in almost every case. I have, for example, both CD-4 and half speed mastered versions of Doobie's Captain and me, and regular version played through SQ sounds 70% as discrete as CD-4 version using CD-4 decoder. I can't explain it other than regular mix having so much out of phase information panned left and right in front channels, that SQ decoder picks it up and places it back. Even if not entirely correct, it is very pleasing nonetheless. But I am using a cartridge with very high stereo separation, it certainly helps.A lot of early Steely Dan albums perform similarly (they also sound decent using QS). Paul Simon early albums are SQ quadraphonic even in stereo versions. And the list goes on. For a while I had both Dolby Pro and DTS Neo decoders in same system as Sansui SQ and QS, and I compared them, and in my opinion using SQ and QS for regular stereo sources is not that different than using Dolby and DTS for the same. With analog sources I much preferred SQ and QS, so I left it at that.