OK - tell us! How did the encode/decode under essentially laboratory conditions compare to the original discrete tape??? I'd love to know. I never had much QS as my decoder was rubbish, but when I got my QSD-2 that all changed. Now I am a fan!
Well it was the prevailing (mis-) concept of quaddies at the time , including me that if you had ever heard a QSD-2 you thought: " Wow! If the D-2 sounds that good think how much more separation the D-1 must have! It's the pro-fessional unit so it must be really good!".
Of course it eventually dawned on me that D-1 or D-2 couldn't have any more separation than is in basic circuit design that is about 20>25 dB separation any direction decoding QS. However the D-1 obviously has tri-band decoding so what it offered is more
stable decoding.
The Vario-Matrix end effect is to sharpen the focus on dominant sounds but blurs & spreads out the lower level sounds as an expense. If you have musical info (or test tones) in differing directions & if they are separated by wide frequency ranges the tri-band will sound better. A good example I think is the Moody Blues track
Beyond on the
Children's album. It has heavy bass & drums center front but if you compare D-1 to D2, the former also shows excellent L/R separation of mid/high in the rear speakers. The D-2 will keep the bass center front where intended but it's just kind of a collapsed sound field in the rear.
My other impression of doing this testing way back when is the D-2 is quite bit cleaner & more detailed than the D-1. Another good example is on that same albums 1st track,
Higher and Higher, when the lead guitar comes in I remember thinking it was just sort a guitar sound in D-1 but with the D-2 you could detect a texture, a buzz from the fuzz he was using or what ever caused it. Nothing to do with decoding it's just the the D-1 was such an ambitious & complex product implemented with what would we would consider very mediocre analog components today. And all together it is a challenge to get good clean sound from source to encode to decode. Even the
QSE-5B had mediocre specs by today's standards... 1% distortion, 20Hz > 20kHz no dB tolerance given, and noise floor of only -70dB. I don't think specs tell the whole story but it helps pick out some weak spots.
The discrete R2R version sounded the best both fidelity & soundfield wise. But I'll be honest switching between the discret, D-1 & D-2 you could hear some differences but after maybe 10>15 secs your ear/brain acclimated & the longer you listen the less you tend to notice the differences.
I'll also tack on here what I've said elsewhere.... I have taken discrete Hi Res audio from Suzanne Ciani's album & QS encoded digitaly in Adobe Audition. When played pack through the Surround Master v2 the difference is completly undetectable between discrete or encode/decode. I don't mean it was almost no change, I mean they sounded exactly the same to me both soundfield & fidelity with very close level matching.
That's progress!