I think the intent of the Surround Master has been seriously misunderstood here. This product was aimed mainly at the quadraphonic enthusiast, who still has, and enjoys, the matrix-encoded LP's of the quad era. The matrix decoders of the 70's differed greatly in their ability to properly decode those records with any great sense of separation, but the Surround Master takes on the best of them at a fraction of what would have to be spent for top-of-the-game separate decoders.
There are two models, as specified in the review. One, with "Involve" mode only, does a great job of properly decoding the Sansui QS matrix, as well as Dolby Surround. it's also capable of extracting the hidden information in stereo recordings to create a realistic surround field from them. The Surround Master does this as well as Sansui's finest QS decoders. The upgrade model adds the SQ matrix as well, handling that system with separation equal to, or better than, the best (Tate DES) SQ decoders of the late 70's or early 80's. A selector switch on the front of the unit allows selecting the mode as needed for the recording.
In addition to being able to play the legacy quadraphonic matrix systems of the quad era, the Surround Master also decodes Dolby Surround with excellent separation. The 5.1 output of the Surround Master can be connected to the 5.1 external input of earlier Dolby Pro Logic receivers that predate the updated Pro Logic II capability. So, for the surround enthusiast who has both records from the quad days, and movies that are in Dolby Surround, the Surround Master makes sense. I could even see it being used in car audio systems, too!