Lou Dorren: A new CD-4 Demodulator!!! [ARCHIVE]

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I very much doubt that the Involve crew is going to pursue anything with CD-4. The idea with their processor is that it can process any stereo signal. Making something just for the very limited CD-4 catalog (a finite and dwindling number of aging physical discs) is way too small of a market for them.

Lou Dorren's unit is (was?) squarely aimed at this niche market -- us here at QQ. His background in the technology makes him the perfect person to pursue this.

I am still holding out hope. There is a schematic and apparently a prototype. Maybe the story isn't over.

That said, I bought a JVC CD-4 unit and modded it to use for the time being, and I bought the Involve with the SQ upgrade (everybody on this board should get one of these!). I have stuff to listen to, and I'm not complaining!
 
I think, the most fans wtih an interess for a new CD-4 Demodulator will be the fans from the 70's, when CD-4 war really on the market and they way younger man. Meanwhile this fans may have an age from 60, 70 years and above. Should we wait, that we must listen CD-4 with ear trumpets? So I have an interess, that the demodulator theme must go on. Analog or digital. I am curious, what Chucky may answer about this idea with Digital-CD-4 Demodulator.

Dietrich
 
Well maybe the issue is capital investment for the demods....and if thats the case how much would Lou need to have the circuit boards alone printed up and we build the demods ourselves???I would certainly be interested in contributing to that end if its possible...
Mike
 
Well maybe the issue is capital investment for the demods....and if thats the case how much would Lou need to have the circuit boards alone printed up and we build the demods ourselves???I would certainly be interested in contributing to that end if its possible...
Mike
What's the name of that place/process where people chip in to develop a project?
 
There were only like 500 original orders for the new Dorren CD-4 demod, since that is what set its price. Then as time went by with no demod, people pulled their orders due to the money being needed elsewhere. So if Involve were to do a CD-4 unit, they'd have to expect VERY low sales numbers - and as for software, although SQ had the most material released, CD-4 was 2nd and should we expect everyone to be using CD-4 LP's or could maybe Involve arrange some licensing agreement where the CD-4 albums were digitized at 98kHz or 192kHz in LPCM from pristine albums that have been cleaned up - so even super rare CD-4 LP's could be released? And as I mentioned in my prior post, Spectral Replication could be used to extend the bandwidth of CD-4 to the full 20kHz instead of the 15kHz cut off (which was more like 10 or 11 kHz on most demodulators. The carrier signal, once demodulated, wouldn't need to be spectrally replicated since we can't really hear directionality at those high frequencies - so the mono HF baseband signal would do. The bass could be taken down to 20 Hz too since the official CD-4 spec was 30 Hz. Down there I would add phase shifts of a few degrees between each channel to make the bass sound more natural since bass was almost always recorded in mono on all LP's.

If, in transcribing the CD-4 LP's to LPCM discrete matrix files (since CD-4 was really a discrete matrix and not a true discrete system) the LP's baseband RIAA EQ and the HF FM/PM/FM carriers and JVC's ANRS NR system were all pre-decoded, the resulting CD-4 digital decoder would need much less circuitry - and the, what, 40ms delay between the baseband and HF carrier could be pre-processed too - the CD-4 digital demod would just have to demodulate the carrier and then dematrix the sum and difference baseband and carrier signals. And there would be no worries of patent licensing since all the patents have expired - only the Spectral Replication would need licensing.

of course, it would be a major undertaking just to get the rights to digitize the LP's and make them available for download. But really, this is just babble because it ain't gonna happen - I do not even believe that Lou Dorren's demod will ever be made available - it's just a gut feeling but one I have strong faith in. If the demod does become available everyone can post that I'm an idiot and make fun of me - and I'll be first in lie to do so.

one thing I would like to see is receivers built with the ability to have new surround decoders downloaded into their DSP chips, kind of like Sony Vegas or Photoshop. So if someone decided to make a DSP CD-4 demod, you could just upload it to the receiver and delete it at any time - or, if memory allowed, daisy chain them, like a DBX or Dolby SR decoder with a true QS Qunitaphonic decoder for Tommy - or Cinema Digital Sound for special releases, if we could get them, of Dick Tracy and T2 - or a Todd-AO decoder for 5 speakers across the front with Perspecta surrounds, etc...

Martin Willcocks, who was the sole inventor of the Tate DES, when I talked to him about 2 years ago, had designed a 16-pole 90 degree phase shifter and said that with DSP it could easily become a 50 or 60 pole phase shifter - and he had also come up with new decoding modifying matrixes for the B- Matrixes applied to the Matrix Multipliers in the DES - they were designed to deal with the odd phase relationships that the Position Encoder and London Box could create and since the SQ system and DES is a 3-Axis decoder (QS and all others are only 2 axis on the Energy Sphere) and since the DES can recognize and decode all three axis simultaneously, a multi-band (like the QSD-1) decoder could 'rotate' between the different SQ modifying matrixes in each band on SQ encoded recordings with very complicated phase relationships, like the Buddy Rich CD and LaserDisc or David Essex's 'Rock On'. While he is no DSP engineer, Martin said that talking to DSP engineers made him think that 2 SHARC chips would be enough for it. Plus features like adjustable 2-channel stereo-to-SQ synthesis could be added along with phase correction for poorly aligned LP systems and a 5-10 ms look ahead so everything would be decoded before reaching the speakers. Boosts and rotations of the energy sphere and phase could be done too to make other decoders, like EV-4 (both versions) and correct Dolby Stereo decoding which the Fosgate Tate does not do - and the DSP receiver system would have 8 speaker feeds, as Ben Bauer always wanted for SQ since we cannot hear pair-wise mixed phantom side images- only Aphex ever implemented 8 channel outputs in their AVM-8000 SQ decoder they made in 1986 - unfortunately, it was a gain riding SQ decoder and not a true cancellation decoder so it didn't perform well, providing only 10db of separation between channels, which they did to reduce audible side-effects of the gain riding. Their later, true cancellation decoder for Dolby Stereo films, the ESP-7000, also had 8 speaker feeds, including center back (which makes me wonder how Dolby and THX got a patent on Dolby EX since the idea was obvious and had clear prior art - Plus PanaLogic had presented Jurassic Park with a center surround in an Australian theater back in 1993 using their PanaLogic decoder)

OK, as typical, I've babbled on too long - I have CBS's Quadraphonic Gala LP playing via my Fosgate Tate (the LP was originally produced to show off the Paramatrix decoder, but we all know how that went). Anyway, the music has kept me writing, but its over now - Maybe the CD's of Chase or Annie should be played next???

BTW, does anyone have a DTS encoded or BD/DVD-A encoded recording of an SQ album decoded by Peter Scheiber's 360 Degree Spatial SQ decoder? I've always wanted to hear that decoder and I've never had the opportunity. Nor have I ever found the extensive white paper he wrote about its inner workings.
 
Are the CDs of Chase and Annie still SQ encoded? Interesting.

I heard Peter Scheiber's 360 degree Spatial Decoder years ago when it first came out at a high end audio store in San Francisco. It was very impressive. The emphasis was on fidelity and smoothness, not separation.
They played the Manhattan's SQ disc. Very cool !

If Martin Willcocks could whip up a new version of his decoder for SQ, QS and Stereo Enhancement there would be interest here. Keep us informed !
 
Are the CDs of Chase and Annie still SQ encoded? Interesting.

I heard Peter Scheiber's 360 degree Spatial Decoder years ago when it first came out at a high end audio store in San Francisco. It was very impressive. The emphasis was on fidelity and smoothness, not separation.
They played the Manhattan's SQ disc. Very cool !

If Martin Willcocks could whip up a new version of his decoder for SQ, QS and Stereo Enhancement there would be interest here. Keep us informed !

Yes, the CD of Chase "Open Up Wide" is SQ encoded - I think the booklet even says so. The original CD release of Annie is SQ encoded - the remastered/ remixed version is not and sounds awful. Annie on CD is fantastic because it was a direct multitrack Position Encoded to 2 track SQ master tape with no intermediate 4-channel tape made. I believe there are a few portions that use the London Box for Center Back instruments. Since both Chase and Annie don't have all of LP's phase errors and rumble that 'confuse' the decoder, they sound practically discrete. There's no instrument shifting or logic action audible.

The "Alternate" decoding mode on the Fosgate Tate 101A was done as a concession to Peter Scheiber - it slows down the logic, reduces separation and makes everything smoother with less distortion. At one AES convention CBS had a listening booth where you could hear the Paramatrix, 360 Spatial Decoder, Shadow Vector and a discrete component based Tate DES decoder, oh, and a CBS/Motorola IC based Full Wave-Matching Logic W/Vari-Blend decoder - and switch instantly between them and vote on the best sound/decoding - when the votes were tallied, the Tate was chosen 90% of the time as the best decoder. Sony was supposed to be there with a Vector Cancellation decoder of their own design, but didn't show up, which is a shame - from the patent, it looks like a good, clean simple design that would work well. I think this AES convention happened just after the FCC declared that SQ had the best mono or stereo performance and best 4 to 2 fold-down of all 4:2:4 and 4:3:4 systems tested and approached the performance of the discrete mater tape with such a small margin that it was the best system submitted - and with USQ could become a fully discrete FM or LP system - so CBS was pretty pleased at the times. In fact, CBS actually officially renamed the system USQ - for Universal SQ - but that name was hardly used and when CBS basically have SQ to TATE Audio, Tate always called it the Tate/SQ Stereo Surround system, not wanting to use the word "quadraphonic". And they also started calling it a 5:2:5 system as the follow up Fosgate Tate decoder was to have a logic derived center channel output - but Jim Fosgate tired of Gary Reber and Wes Ruggles and dropped using the DES IC's, then joined up with Peter Scheiber and his 360 Space Matrix that got rid of the "difficult" 90 degree phase shifters in the decoder. Martin Willcocks was tired of Ruggles and Reber too and left the company and then introduced Scheiber to Shure, Inc, who, with Dolby's help, designed their - still amazing- Acra-Vector decoders. They are the only logic decoders for the home that precisely duplicated the performance of the modified Tate Dolby CAT-150 surround decoders Dolby used until 1986 or so when they tired of Ruggles/Reber and designed their own Pro-Logic system.

i have an article from Peter Scheiber about the 360 Spatial Decoder and he stated that the decoder used a "modified" version of the SQ decoding mode that he came up with himself for sharper side image localization and more in-phase relationships among the four speakers that made instruments sound fuller and smoother. Of course, Ben Bauer fixed all the problems that SQ had so the Fosgate Tate didn't need a modified matrix like Scheiber's decoder.

Peter is a bitter person now - both Ray Dolby and Dolby Lab's really screwed him over badly and he claims he originally came up with the feedback logic PL-II uses and Jim Fosgate stole it from him. All the licensing money he earned from CBS, Sansui, EV and others he squandered suing everyone and is now a broke and very bitter person. He was treated badly by the studios and Dolby but should have never represented himself in every lawsuit he initiated.
 
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Hmm, what about the self-titled "Chase" by Chase? Also an SQ Encoded CD?

On Annie, I guess we will have to keep an eye out for the catalog number that was SQ encoded. With remasters, unless the person at the console is watching the phase relationships, any SQ or matrix encoding can end up on the cutting room floor. As apparently happened here.
 
Hmm, what about the self-titled "Chase" by Chase? Also an SQ Encoded CD?

On Annie, I guess we will have to keep an eye out for the catalog number that was SQ encoded. With remasters, unless the person at the console is watching the phase relationships, any SQ or matrix encoding can end up on the cutting room floor. As apparently happened here.

This is the SQ encoded CD of Annie http://www.amazon.com/Annie-1977-Original-Broadway-Recording/dp/B000F3OWK6/ref=sr_1_38?ie=UTF8&qid=1379110576&sr=8-38&keywords=annie+soundtrack+broadway - the later 1998 release w/extras is not SQ encoded. The remixed version was done from the original multi tracks so its not the SQ release remixed.


Here's the Chase CD - I thought it was called Open Up Wide and didn't realize it was their first self titled album.
http://www.amazon.com/Chase/dp/B000002R4Z/ref=ntt_mus_ep_dpi_2


Both of these decode amazingly on the Fosgate 101A and are worth getting if you like the music.
 
This is the SQ encoded CD of Annie http://www.amazon.com/Annie-1977-Original-Broadway-Recording/dp/B000F3OWK6/ref=sr_1_38?ie=UTF8&qid=1379110576&sr=8-38&keywords=annie+soundtrack+broadway - the later 1998 release w/extras is not SQ encoded. The remixed version was done from the original multi tracks so its not the SQ release remixed.


Here's the Chase CD - I thought it was called Open Up Wide and didn't realize it was their first self titled album.
http://www.amazon.com/Chase/dp/B000002R4Z/ref=ntt_mus_ep_dpi_2


Both of these decode amazingly on the Fosgate 101A and are worth getting if you like the music.

Interesting. What is the year on your Chase CD? It looks like there are 4 Stereo CD versions of that floating around !
 
Mine is a lossless iTunes file that I made a CD from - I got the original CD from the local library and recall that it was a 1980's release. Apparently the original master tapes for the album were lost so all that exists is the 2-channel SQ master EQ'd for LP release and all versions come from that, even the Japanese CD release. While its been re-EQ'd for CD, it's still bright without a lot of dynamic range. I usually end up using my dbx 128 expander on it. I do remember that the back of the case said it was SQ encoded. I did scan the booklet so I'll see if I can locate it and get a CD copyright date.
 
Mine is a lossless iTunes file that I made a CD from - I got the original CD from the local library and recall that it was a 1980's release. Apparently the original master tapes for the album were lost so all that exists is the 2-channel SQ master EQ'd for LP release and all versions come from that, even the Japanese CD release. While its been re-EQ'd for CD, it's still bright without a lot of dynamic range. I usually end up using my dbx 128 expander on it. I do remember that the back of the case said it was SQ encoded. I did scan the booklet so I'll see if I can locate it and get a CD copyright date.

Hmm. The ones I'm seeing are from 1996, 2003 and 2012. Some are domestic and one is the Japanese Import you mentioned.
 
Off topic for a CD-4 thread... but
My Chase SQ CD is 1996 - One Way Records - A 26660, Sony Music Special Products
UPC 0 79892 66602 1

vinylguy4
 
Lou,

I wondered if you would be willing to help us fill in the blanks with our software based CD-4 Demodulator project.

Using your documentation we found here: http://www.johana.com/~johana/dorren/ and other assorted manufacturer repair and user manuals we have had some success. However we are missing some detail and estimated some of the variables to get the early versions working.

So far we have implemented a software implementation of the Phase Lock Loop and in addition we are experimenting with a Phase Discriminator as an alternative to demodulate the difference signal.

The sort of details we are missing or would like confirmation of are for example the cut-off frequencies and roll-off of some of the filters, PLL gain and PLL lowpass frequency and granular detail around the ANRS.

Any help you are willing to offer would be most appreciated.

Also what happened to the "New CD-4 demodulator" you were working on?

Best regards,
Tim
 
Due to his recent health issues he describes earlier in this thread and the amount of paying work in which he is currently involved, - done by necessity in order to eat - Lou sees this thread - and this board - very infrequently.

You might be able to get the information and/or schematics you need from other retired CD-4 engineer members such as Greg Bogantz or the guys from the JVC Cutting Center in Hollywood.

Go on the Lathe Troll form - which concentrates its' information on record cutting and its' processes - and see if you have any better luck there.

And here's hoping Lou gets better healthwise so he can hang around us more often.
 
it was always my feeling for a fear or bad healthy situation, when a development will need so many years. There is alsways the possibility, that healthy problems could stop all the many hard and strain working till this moment. On the other hand, Lou has told in the past, that the protoyp is ready and should send to Jon soon. It is a well idea, when other technical members like to develope a CD-4 Demodulator. But also the engineers in Australiea would help to finish the Demodulator and to build the needed or ordered items. I have written today also something about this subject in the Invole thread. Lou would need anyway a technical stuff for the duplication.
When the prototyp is ready, then there can be not a barrier for the manufactoring the needed 150 (?) demodulators, which are further on Dorren Demodulators, independing which people or technicans have made the duplication.

Dietrich
 
I hope Lou gets better soon. I'm a very patient person, so whenever a new CD-4 demodulator becomes a reality, I'm prepared for it. I set money aside years ago, and I won't touch it for anything else.
 
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