(1972-10) RE/P mag - Advantages of the Sansui QS Coding System

[Soundfield]

As late as 1970 the BBC Paris Theatre concerts were mono. The voices in my head are saying that John Peel even explicitly mentions medium wave during one or more introductions (i.e., what we in the US refer to as "AM", which at the time was strictly low-fi mono).

I don't think that was really anything to do with the facilities at the Paris Studios. Until the coming of commercial radio, most rock and pop music in the UK, whatever the source was broadcast in mono (on Medium wave) until 1987/8 when the BBC's pop channel (Radio One) started to get FM frequencies allocated as the Police were moved from the low end of VHF Band II. However some rock and pop shows (such as John Peels) were also given air time for a few hours each week on the middle of the road channel, Radio Two, which along with Radios Three and Four had been given FM transmitters as far back as the late 1950's / early 1960's. Lots of stuff was certainly recorded in stereo at the Paris studios (actually, as an old theatre the studios were used mostly, not for concerts but for radio comedy such as The Hitchhiker's Guide).

 

[Doug G.]

People seem to be jumping on you unfairly. If the SQD-2050 sounds discrete to you that's great! Obviously other more advanced decoders exist, they aren't discrete either but they can sound darn close.

Yeah, some people are so touchy. I guess they are trying to tell me I don't hear what I hear. I don't care.

Doug

 

[Doug G.]

But it's not discreet, SQ never will be even when some think it sounds so.

You think I don't know that? I said it SOUNDS discrete. I didn't say it WAS discrete. Are you aware of the whole "how many dB difference between channels makes a sound appear to come from a certain direction" subject?

No system is ever completely discrete. There is always some crosstalk, even if it's 80 - 90 dB down.

And don't worry, I have CD-4 if I want to really approach discreteness.

Doug

 

[Doug G.]

y something with regards the two comments mentioned above.

1 - Technically the Sony SQD-2050 is completely incapable of delivering discrete decoding of any matrix encoded material

2 - Theoretically it isn't possible to create a discrete replica of the original audio used, but i think it's fair to say that we should 'Never Say Never', the way technology has moved since the inseption of the quad matrix systems you never know what will be coming down the line in the future.

Like I said, I didn't say the SQD-2050 delivered discrete performance. I said it SOUNDS like it does, much of the time. It only takes a certain dB difference between channels to create the effect.

Doug

 

[kfbkfb]

12db (Involve Audio: more than 12dB separation not needed)

IIRC, the later model Sony Full Logic SQ decoders provided 12dB - 15dB separation, so the logic action artifacts were minimized and (in some cases) the decode sounded similar to Discrete.


Kirk Bayne

 

[furui_suterioo]

Where does the QSD-4 fit into the multitude of Sansui QS decoders?

 

[jaybird100]

Each quad system had it's strengths and weaknesses, manufactures would tout their respective systems strengths will ignoring or downplaying it's weaknesses.

The BBC was concerned with 100% mono compatibility, unnecessary IMHO. Did you notice mention of Electro voice's Universal Decoder? It decodes SQ,QS and EV-4, without switching, a fantastic idea if it would of worked well. Nice to see publications like this, I love to look at the old professional studio equipment.

That EV "Universal" decoder was far from universal. It was a compromise for both SQ and the original EV matrix, and did neither well. Obviously, that includes QS. Valiant effort though it was, it fail miserably.

 

[jaybird100]

But it's not discreet, SQ never will be even when some think it sounds so.

The SQD-2050 was a "partial logic" decoder, in that it used gain riding to enhance front-back separation. Problem is, it created a "pumping" effect. The RM circuitry in that decoder is basic; no logic applied. As for SQ sounding discrete, the Tate System SQ decoders were touted as providing much higher separation than previous decoders could, and I had one of those. It did an admirable job, but lacked the ability to handle QS/RM. The Surround Master v2 does both systems incredibly well, providing 'virtually discrete" separation from both systems. Of course, no matrix can be fully discrete, but when you can get separation as good as the SM provides, it really doesn't seem to matter. Since I also have the Evaluation Encoder module, and have used it, in the Smart Encode mode, to create CD's that are matrix-encoded from the original discrete source. Played back through the SM, they sound so close to the discrete that you'd be hard-pressed to tell the difference on a blind A-B comparison. Play them back in stereo, and they sound excellent. These are for my own use, by the way, in case the "legal eagles" are looking.

 

[atrocity]

I don't think that was really anything to do with the facilities at the Paris Studios.

Sloppy wording on my part. What I meant was that even as late as 1970 some classic shows recorded there were only mixed to mono because, as you point out, that's what was being broadcast.

 

[artwwweb]

In a of lot music yes, but the BBC wanted quad for more than just music. It wanted a format that was universal in application and was keen on using it for radio drama for example.

The point about drama is very important. When we think of quad music, we think of something that took months to record and days to mix. A lot of drama is basically recorded live, with a few re-takes, and then edited. And the imaging on radio drama is lot more subtle than on a film, so when you listen you can place people precisely in their position rather than simply left, centre or right. So if a group of people were recorded standing in a room, it would definitely be a problem for those at centre back to be lost/ reduced. And of course they often walk around so it's not simply a case of saying 'don't stand in the centre rear'.

Also, a lot of music was and is broadcast live by the BBC, often not in their own studios, so there would be even less opportunity to check that a quad broadcast was sounding ok in mono.

 

[artwwweb]

[BTW, my previous post reminds me of a great story: when Hendrix did a recording ession for the BBC in 1967, the engineers were astounded that they could hear him playing - through the 'sound proof' glass. As they were watching in amazement, the producer noticed a "little old lady" (as he later described her) standing behind him. So he introduced himself and she said she was the producer of a classical music session two floors above, which kept being interrupted by electric guitar noises! He explained that they had nearly finished recording, so would it be alright if she waited a while to finish her session? And she replied, "Not really, we're going out live on Radio 3..."]

 

[Doug G.]

The SQD-2050 was a "partial logic" decoder, in that it used gain riding to enhance front-back separation. Problem is, it created a "pumping" effect. The RM circuitry in that decoder is basic; no logic applied. As for SQ sounding discrete, the Tate System SQ decoders were touted as providing much higher separation than previous decoders could, and I had one of those. It did an admirable job, but lacked the ability to handle QS/RM. The Surround Master v2 does both systems incredibly well, providing 'virtually discrete" separation from both systems. Of course, no matrix can be fully discrete, but when you can get separation as good as the SM provides, it really doesn't seem to matter. Since I also have the Evaluation Encoder module, and have used it, in the Smart Encode mode, to create CD's that are matrix-encoded from the original discrete source. Played back through the SM, they sound so close to the discrete that you'd be hard-pressed to tell the difference on a blind A-B comparison. Play them back in stereo, and they sound excellent. These are for my own use, by the way, in case the "legal eagles" are looking.

I have never heard any pumping effects from my SQD-2050, at all. It's very smooth. It's no different from a regular two channel preamp.

Doug