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PsudoQuad from vinyl on Surround?

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PsudoQuad from vinyl on Surround?

Postby IndigoRock2001 » 11 Jun 2018 18:48

In the 70's my father had the whole Quadraphonic setup incl CD4 cartridge and SQ Quadraphonic LP's. The couple of quadraphonic formats used phaze inversion (whatever that is) to encode the quad sound. I noticed that some very "studio" albums like the Beatles decoded inadvertantly into 4 channels. I have my Audio Technica ATLP120 with an AT440MLB cartridge playing through my surround system. I can also pick pure analogue which I prefer. Though 7 channel Stereo creates a very pleasing subtle surround feeling. Fills the room.
But I was wondering if with the use of a different cartridge inadvertant phaze inversion could be picked up and processed by the Dolby Surround channel to produce psudo Quad. Has anyone any experience playing with this?
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Re: PsudoQuad from vinyl on Surround?

Postby KentT » 12 Jun 2018 17:46

Of the Quad LP formats, Sansui's QS was for me the best. Didn't require as finicky setup, the records played on Stereo systems without damaging them for Quad playback. And the Sansui QS Vario-Matrix had the best simulated Quad from Stereo discs of all the systems.
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Re: PsudoQuad from vinyl on Surround?

Postby EdAInWestOC » 12 Jun 2018 20:54

What you are talking about is out of phase information.

The CD-4 system is different from the other systems that all utilized out-of-phase information to create rear channel information. Sansui QS, Columbia's SQ and ABC Command Quad all used out of phase information to create the rear channel stuff.

The out of phase systems were called matrix systems and the LPs include out of phase information that can be reproduced as if you have a quad system. It is especially prominent if you have bi-polar speakers, like Magneplanars, with rear wave projected sound.

The type of speaker, the placement of your speakers and the proximity to side walls all figure into how well the out of phase info is reproduced.

Ed
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Re: PsudoQuad from vinyl on Surround?

Postby denvertrakker » 12 Jun 2018 21:06

To answer the OP's original question: You do not need a cartridge different from what you have now for playback of synthesized surround from QS, SQ, EV4 or any other out-of-phase system. Only CD4, as EdAInWestOC mentioned, requires a special cartridge (and other stuff too).

Various surround programs - such as Dolby ProLogic, PLII and similar - will produce a surround effect, although it will vary depending on the source. In general, the more microphones involved in recording the more out-of-phase information available to "process".
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Re: PsudoQuad from vinyl on Surround?

Postby mythrenegade » 14 Jun 2018 04:18

I find it curious that quad recordings are not sold on blu-rays as 4.1 surround mixes. A niche market, sure, but I would love to hear some of those old recordings on my modern surround setup.
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Re: PsudoQuad from vinyl on Surround?

Postby circularvibes » 14 Jun 2018 04:56

mythrenegade wrote:I find it curious that quad recordings are not sold on blu-rays as 4.1 surround mixes. A niche market, sure, but I would love to hear some of those old recordings on my modern surround setup.


Many have been rereleased. Check out this surround forum for more info. http://www.quadraphonicquad.com Many have come out on SACD, DVD Audio and Blu Ray Pure Audio. Dutton Vocalion from The UK is scrounging from Sony's vaults. Deutsche Grammophon just rereleased a bunch of Bernstein and Pentatone also released a bunch. That is just for starts.
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Re: PsudoQuad from vinyl on Surround?

Postby EdAInWestOC » 14 Jun 2018 05:02

The matrix quad systems had rear channel info but the placement was vague at best. The CD-4 system was capable of much more discrete placement but that system had its problems.

Even regular LPs have out-of-phase info that can result in some interesting effects. I use Magnepan speakers and those speakers in my old home had some interesting effects.

The right wall would have instruments placed there on some LPs. It was not supposed to be, it just turned out that way.

Back in the day, when I had a quad system, I got some pretty good effects from many regular stereo LPs. The SQ, QS and ABC Command Quad LPs would be better sometimes but it was a crap shoot.

The CD-4 system was a failure due to problems with extracting the 30kHz difference information reliably from the LPs. I owned the TOTL Technics CD-4 demodulator back then and no matter what you did, things were not that great in CD-4 land.

When it did work it was nice but working is a loose term. I layed out lots of money on my quad system and it was not great at placing instruments where they were supposed to be. There were other problems but suffice it to say that quad was a doomed experiment from the beginning.

Lots of equipment was sold but the systems didn't work very well.
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Re: PsudoQuad from vinyl on Surround?

Postby Spinner45 » 14 Jun 2018 05:19

And all this is why I never liked or delved into the "quad" stuff.
Too many issues.
Since 1977 I've been saying: "All you need is just TWO good channels."
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Re: PsudoQuad from vinyl on Surround?

Postby circularvibes » 14 Jun 2018 05:40

Spinner45 wrote:And all this is why I never liked or delved into the "quad" stuff.
Too many issues.
Since 1977 I've been saying: "All you need is just TWO good channels."


Then why not quote Phil Spector with his "Back To Mono" buttons?

Quad is not that difficult with the right equipment. I had an issue with CD4 and bought a few expensive (for me) cartridges, tried a different table and about 6 demodulators. Turns out the problem was simply the RCA cables on the tables. A really easy fix and all my cartridges, demodulators and CD4 quadradiscs all play well. Even the difficult ones like Cat Stevens Greatest Hits. There were a few titles that were duds but surround is still more satisfying to me where it is available. I do listen to stereo and mono records as well. Heck, I prefer rock"n"roll on 78's.
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Re: PsudoQuad from vinyl on Surround?

Postby circularvibes » 14 Jun 2018 05:44

EdAInWestOC wrote:The matrix quad systems had rear channel info but the placement was vague at best. The CD-4 system was capable of much more discrete placement but that system had its problems.


That would be true of the early matrices like Dynaquad or EV4/Stereo4, but they were designed to give a bit of space to the music, not add directionality. SQ and QS were significantly better with the better decoders like the Sansui QSD1 or the Sony SQD2020 or Fosgate Tate.
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Re: PsudoQuad from vinyl on Surround?

Postby Spinner45 » 14 Jun 2018 07:28

circularvibes wrote:
Spinner45 wrote:And all this is why I never liked or delved into the "quad" stuff.
Too many issues.
Since 1977 I've been saying: "All you need is just TWO good channels."


Then why not quote Phil Spector with his "Back To Mono" buttons?

Quad is not that difficult with the right equipment. I had an issue with CD4 and bought a few expensive (for me) cartridges, tried a different table and about 6 demodulators. Turns out the problem was simply the RCA cables on the tables. A really easy fix and all my cartridges, demodulators and CD4 quadradiscs all play well. Even the difficult ones like Cat Stevens Greatest Hits. There were a few titles that were duds but surround is still more satisfying to me where it is available. I do listen to stereo and mono records as well. Heck, I prefer rock"n"roll on 78's.


I've had the pleasure to audition all the "quad" stuff when it was new in the 70's, including automobile sound setups.
At its best and most expensive range, it just never floated my boat.
So I stuck to and was satisfied with good old "stereo".
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Re: PsudoQuad from vinyl on Surround?

Postby KentT » 14 Jun 2018 14:53

CD-4 was a pain in the rear end. And in 1970's mass market, oil crisis era vinyl production USA vinyl real life, not a doable system. The records had to be 1/2 speed mastered, needed to be made in Japan on JVC Super Vinyl for them to have lasted very many playings (which would have been $13 each) and also were limited to 15 Khz top response. Open reel tape was the best format for discrete Quad. Sansui's QS was the only system which could be used on average phonographs, the best of the matrix formats, and the only system ever practical for FM broadcast, the only truly backwards compatible format with Stereo, and practical for the US Record Industry to implement CD-4 was not practical, broadcasters hated SQ (phase problems for them), and backwards compatibility was necessary for single inventory LP and 45 RPM sales.
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Re: PsudoQuad from vinyl on Surround?

Postby Spinner45 » 14 Jun 2018 17:37

KentT wrote:CD-4 was a pain in the rear end. And in 1970's mass market, oil crisis era vinyl production USA vinyl real life, not a doable system. The records had to be 1/2 speed mastered, needed to be made in Japan on JVC Super Vinyl for them to have lasted very many playings (which would have been $13 each) and also were limited to 15 Khz top response. Open reel tape was the best format for discrete Quad. Sansui's QS was the only system which could be used on average phonographs, the best of the matrix formats, and the only system ever practical for FM broadcast, the only truly backwards compatible format with Stereo, and practical for the US Record Industry to implement CD-4 was not practical, broadcasters hated SQ (phase problems for them), and backwards compatibility was necessary for single inventory LP and 45 RPM sales.


Quad sound only lasted a couple of years, it fell out of favor due to its confusing use and questionable quality, along with the costs which people didn't find worth it.
It's funny, but when it first appeared on the scene back then, I KNEW it was lousy and wouldn't last.
And I was right.
The bottom line: it was a "fad", a marketing gimmick, to hopefully boost the income of manufacturers.
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Re: PsudoQuad from vinyl on Surround?

Postby billrog787 » 15 Jun 2018 13:15

I had a Sugden quad system back in the day, QS and SQ, but soon ditched it and back to stereo as it did not float my boat. I do love surround sound for live music though, I really enjoyed the Pink Floyd concerts that I went to in England that were in surround with the "azimuth co-ordinater", some of the best rock shows I have ever experienced.

Bill.
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Re: PsudoQuad from vinyl on Surround?

Postby Pikey » 15 Jun 2018 14:17

I remember experimenting with a 'Hafler' style lash-up many years ago , basically wiring up a 3rd speaker (across the +ve terminals of the normal two channels?) and putting it at the back of the room ... interesting for a while!
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