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

[kfbkfb]

Recording-1972-10.pdf (worldradiohistory.com)
^^^
Are you prepared to make A-B comparisons between a discrete four-channel original and the QS-encoded and decoded version of the same material - without being able to tell the difference?


(Found this looking for something else, strangely, QS didn't do well in the 1974 BBC tests or the 1975 NQRC tests)


Kirk Bayne

 

[par4ken]

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.

 

[willothewisp]

Parken. Perhaps you don't live in the UK but at the time of the quadraphonic experimental broadcasts the majority of listeners to the BBC broadcasts were on mono trannies, hence the need for mono compatibility.

 

[par4ken]

Parken. Perhaps you don't live in the UK but at the time of the quadraphonic experimental broadcasts the majority of listeners to the BBC broadcasts were on mono trannies, hence the need for mono compatibility.

Yes but normally there is little of any importance encoded in the centre back position. As sounds are panned across the rear in QS the sound will reduce in volume, disappear at the centre position then reappear as it's panned father across. Sansui suggests that this is an advantage. On mixes that contain ambience in the rear, mono mixing will enhance forward (important) parts of the mix while reducing the parts that would actually tend to cloud the mono mix.
The BBC chose to produce a phasey stereo mix instead.

 

[Sonik Wiz]

Are you prepared to make A-B comparisons between a discrete four-channel original and the QS-encoded and decoded version of the same material - without being able to tell the difference?

Been there, done that. In the late 70's for a short while I had the magic combination of a Sony 4 ch R2R, a Sansui QSE-5B encoder & a QSD-1 decoder. I used my 4ch reels of Moody Blues material to compare as I thought that music & mixing would be a good test for matrix decoding. The level input on the QSD-1 made it very easy to match the levels straight from the R2R which plugged into the discrete input on the QSD-1.

Going from discrete tape to encode/decode it was easy to hear a slight degradation in sounfiled distinctness. But after about 15 secs the ear/brain connection adapted & everything seemed as good as before. Going back to discrete the soundfield opened up & you could hear the difference but not by much. It certianly convinced me with good quality encode/decode I could be very happy with matrix. The biggest change was a bit of muddiness not related to the surround sound but just a bit of loss in fildelity due to the extremely complex signal chain in analog 70's gear.

When Suzanne Ciani made available her LIVE Quadraphonic recording by download in lossless discrte surround I jumped at it. I also did a QS encode on my PC to see how the discrete compared to encode & decode on the SM v2. This time around I was amazed. I simply could not hear a difference to matter how many time I replayed a section or almost forced mysely to find a change. The QS encode/ decode sounded exactly like the original discrete mix. Sometimes you can find clear improvement over nostalgic vintage gear!

 

[Sonik Wiz]

Parken. Perhaps you don't live in the UK but at the time of the quadraphonic experimental broadcasts the majority of listeners to the BBC broadcasts were on mono trannies, hence the need for mono compatibility.

Yup in the UK or USA it seems the requirements of radio stations called the shots. It has occoured to me that the double inventory of quad/stero in stores should have applied to radio stations. Giv 'em their damn stereo mixes & put only quad records in the stores.

 

[willothewisp]

Yes but normally there is little of any importance encoded in the centre back position. As sounds are panned across the rear in QS the sound will reduce in volume, disappear at the centre position then reappear as it's panned father across. Sansui suggests that this is an advantage. On mixes that contain ambience in the rear, mono mixing will enhance forward (important) parts of the mix while reducing the parts that would actually tend to cloud the mono mix.
The BBC chose to produce a phasey stereo mix instead.

The effect on information on the back channels happens on any matrix system based on 90 degree phase shifting, the BBC's way of solving that was to move away from the accepted methods, which did make for an interesting mess

Although there were complaints of phaseyness during the unofficial 1976 tests, a modification of the front channel mathematics for the official 1977 tests solved that.

To prove that one only has to listen to the UK release of David Bedfords album Instructions For Angels.

 

[Soundfield]

Yes but normally there is little of any importance encoded in the centre back position.

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. It produced some very fine plays in quad. After Matrix H was morphed into HJ I must say that I never really heard any 'phasiness' with stereo reproduction of HJ broadcasts.

 

[Sonik Wiz]

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. It produced some very fine plays in quad. After Matrix H was morphed into HJ I must say that I never really heard any 'phasiness' with stereo reproduction of HJ broadcasts.

Once upon a time I visted and coresponded with a great chap by the name of Alan Turner. Lived in Romsey. At that point the BBC were trying all sorts of things including binaural audio. I think what he shared was a dummy head recording of Gilgamesh. It seemed rather low budget but it was certianly proof of concept that stage productions via binaural worked. I bet it sounded really bad over speakers on the radio tho.

 

[Doug G.]

Heck, at the present time, I just have a Sony SQD-2050 to decode SQ and QS records and, even though it is only front/back logic, it sounds darn near discrete much of the time. Great fidelity, too.

Doug

 

[willothewisp]

I think what he shared was a dummy head recording of Gilgamesh. It seemed rather low budget but it was certianly proof of concept that stage productions via binaural worked. I bet it sounded really bad over speakers on the radio tho.

Yea, it still isn't possible to convert binaural to sound acceptable in standard stereo. Guess some things are just plain impossible.

 

[Soundfield]

At that point the BBC were trying all sorts of things including binaural audio. I think what he shared was a dummy head recording of Gilgamesh. It seemed rather low budget but it was proof of concept that stage productions via binaural worked. I bet it sounded really bad over speakers on the radio tho.

The BBC still broadcast a handful of binaural radio programmes every year. They are usually dramas or documentaries that additionally attempt to give the listener a first hand experience of the events, such as being in wild fire, a war zone etc.
I don't think these productions, or indeed the small number of Live Concerts (notably The Proms) which get variously labelled as "immersive sound", "spatial sound" or "3D surround sound" have huge audiences but the BBC seem stubbornly dedicated to the process. There is a quite lot of information on their current development plans, details of some recent broadcasts and production methods and quality evaluation on the BBC R&D web pages-
BBC Binaural Research & Development

 

[quicksrt]

Heck, at the present time, I just have a Sony SQD-2050 to decode SQ and QS records and, even though it is only front/back logic, it sounds darn near discrete much of the time. Great fidelity, too.

Doug

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

 

[Soundfield]

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

A matrix format such as SQ is not discrete in terms of channel separation, and as a consequence its presentation can be disappointingly discreet!

 

[willothewisp]

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.

 

[Soundfield]

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.

That would require more than a perfect decoder, it would require an un-encoder which is not the same thing. It would be akin to unscrambling an omelette into its original eggs!

 

[par4ken]

Heck, at the present time, I just have a Sony SQD-2050 to decode SQ and QS records and, even though it is only front/back logic, it sounds darn near discrete much of the time. Great fidelity, too.

Doug

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.

 

[Sonik Wiz]

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.

About the time I got my Fosgate Tate II I was in contact with a Quaddie in Albuquerque NM. He had some sort of SQ full logic ( I can't recall specific) & I spent considerable time trying to get him to upgrade to something better. Something higher seperation in any direction, fewer or un-noticeable artifacts. In reality his home was all tile floors, stucco walls. Incredibly reflective even with rugs & furniture. All that mattered to him was most possible seperation that he felt full logic SQ was good enough, and because of his homes acoustics it was impossible to hear any pumping. So! He had what was best for him.

There's some interesting info on the progression of SQ decoding on Tab Patterson's web site:

http://4channelsound.com/logic.htm

 

[atrocity]

Parken. Perhaps you don't live in the UK but at the time of the quadraphonic experimental broadcasts the majority of listeners to the BBC broadcasts were on mono trannies, hence the need for mono compatibility.

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).

 

[par4ken]

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 recall FM having any real popularity until the very late seventies. AM (medium-wave's) popularity helped to delay the introduction of AM stereo, which arrived a bit late to save AM's sagging popularity. The CBC's (Radio One) main network, formerly AM (now mostly FM) still broadcast exclusively in mono, even music programs. I sometimes think that Quad was thought of much too soon, most people hadn't even embraced stereo yet.