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

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I don't think he was saying he didn't like CD-4. Just that he liked SQ the best.

Maybe he had trouble with CD-4. That's the usual reason people put it aside and the usual reason for having trouble with it is not following the rules to the letter or, to the groove, as the case may be. Or trying to use inferior equipment.

Of course, it's glorious when it's right.

Doug
 
Yeah, I can relate to that. I too, once liked SQ better. And for the same reason. I was dealing with inferior equipment and it just didn't work right. Now, I feel SQ is OK, but CD-4 is just better. Once you have a decent decoder, it mostly boils down to getting a good cartridge and stylus, and keeping your records clean. Of course, you need a good turntable as well.
 
Yeah, I can relate to that. I too, once liked SQ better. And for the same reason. I was dealing with inferior equipment and it just didn't work right. Now, I feel SQ is OK, but CD-4 is just better. Once you have a decent decoder, it mostly boils down to getting a good cartridge and stylus, and keeping your records clean. Of course, you need a good turntable as well.

I still like SQ better, simply due to its better stereo compatibility. With QS or CD-4 albums, I am always aware I'm listening to a quad-to-stereo playback, whereas with SQ, in stereo, it simply sounds like a good stereo mix. Where QS sounds 'narrow' in stereo and CD-4 can seem to have a center "hole" in stereo, SQ has a normal stereo spread that sounds like a normal stereo (non-quad) mix - but when decoded via the Tate produces a full quad soundstage - and one that's a bit 'bigger'than CD-4 due to SQ's (and all matrix systems) inherent leakage - in other words, SQ via the Tate doesn't sound as "dry" as a fully discrete recording. Except for a few odd moments here or there, I don't notice the logic action of the Tate and when I do hear it, it's over very quickly. And typically, a decoding artifact with the Tate is also audible in stereo due to some odd mixing (Company has mixing errors that make the Tate sound like its mis-decoding, but they are audible on the stereo SQ mix and the discrete Q4 mix too).

So, all around, SQ is my preferred system. It's just too bad the USQ format (combining SQ with CD-4) never got off the ground. Ben Bauer was always working on it and it was his preferred FM quad proposal.
 
Great news, Jon! We need more women here! Welcome, Theresa!

Can't wait until she appears on the CD-4 radar!

Linda
Chix rule!

As a teen I noticed that all my female friends readily noticed the surround effect from my Fosgate Tate II on movies and music - and really appreciated it - but my male friends, even fellow gays, either didn't notice it or didn't give a damn.
 
Hello to all Quadropheners,

First I would like to thank every one for the kind words about Mike. He was a great friend and college for over 35 years and he will be missed.

Now I would like to introduce you to the person who is taking over Mikes position. Her name is Theresa Hahn and she will be overseeing the order confirmation and extra pickup and stylus lists. She has been working with me every year at the Northern California Song Writers convention and she is now taking Mike's position at Xytar.

If you have any questions about your order confirmation, just send her a message.

Jon will be receiving the eval demodulator shortly so watch for his write up.


That is it for now

As we Hams say 73's and as Quadrophoners, CD-4,

Lou Dorren
 
SQ can sound very good. That much I will admit. I have an Audionics Space and Image Composer, and it does a good job with SQ. But I still like CD-4 better. I don't play quad records in stereo, so compatibility is not an issue.

The Quadfather
 
SQ can sound very good.

The Quadfather

It's too bad that CBS own original SQ encoders had such terrible sound quality due to all the low-quality op-amps in the phase shifters. Early Columbia SQ LP's had such a dull sound to them - and paradoxically an etched, gritty, quality too due to the early transistor distortions. At least the CBS phase shifters were accurate to 1 degree. Capitol Records in the US and most European companies that released in SQ used encoders of their own design that employed better circuitry - "Dark Side Of The Moon" is a great example of the sound of a high quality SQ encoder.
 
It is not the right place here to comment technic themes of CD-4. But I would answer wih a short message to the Quadfather in concerning "compatible". I think, that was another mistake of the industry. Those, who would like to listen further on stereo, would buy also further on stereo records. CD-4 should have "only" pure discrete informations, which means in the area of 20-15.000 Hz the channels in front and in the area of 30-45 kHz only the back channels, not the difference infiormations. In that really discrete working the channel separation of front-rear could be for my opinion till 50 dB which have been blow away all the matrix competitors. But the hopefully now finished new CD-4 Demodulator of Lou Dorren will give us also a few dB's more as the usual 30 or less dB's.

Dietrich
 
It is not the right place here to comment technic themes of CD-4. But I would answer wih a short message to the Quadfather in concerning "compatible". I think, that was another mistake of the industry. Those, who would like to listen further on stereo, would buy also further on stereo records. CD-4 should have "only" pure discrete informations, which means in the area of 20-15.000 Hz the channels in front and in the area of 30-45 kHz only the back channels, not the difference infiormations. In that really discrete working the channel separation of front-rear could be for my opinion till 50 dB which have been blow away all the matrix competitors. But the hopefully now finished new CD-4 Demodulator of Lou Dorren will give us also a few dB's more as the usual 30 or less dB's.

Dietrich

Yes, but compatibility has pretty much always been on the 'required' list of features when introducing a new product that improves upon an already existing one. Color television, FM stereo radio, AM stereo radio, stereo television in its many forms around the world, etc... products that are backwards compatible almost always do better in the market than those that are not. So it was only natural for JVC to make CD-4 backwards compatible - not only that, but the difference signal carried on the 30kHz carriers has less information in it than if the rear channels were recorded directly - most of the information is in the sum signal, making the difference carrier signal easier to record and play back on the CD-4 LP, increasing quality. It was a sound engineering choice for JVC to make.
 
OK, when there would have been technical difficulties to store the full informations of the rear channels in the frequency area of about 30 kHz I would understand it, that there could only a storing of the difference signals. But I have never heard till now, that there was such a storage problem. So I have made this consideration, if not a more better channel separation has been possible. And I think, a real better technic needs not a full compatibilty. For example: CD's dont play on LP record players. Compact cassettes not on open reel recorder. But a full discreteCD-4 record, as I thought, could be played even on stereo LP players, of course with only the front informations. But I have never heard, that stereo listener have bought and listened CD-4 records. And I and many known Q-fans have never buyed a stereo record, when the same music from a band or artist could be received with a CD-4 record. Therefore is my consideration, that a compatibility for quadraphonic records (CD-4) has been superfluous. We are all angry about the result of " compatibilty" (and other mistakes by the industrty) which was not helpfull for a quadraphonic success. And I have now the interess to know, which considertions was done by the development of the quadraphonic technics - for example CD-4. But to have an answer for my idea, one should have the possiblity to ask one of the CD-4 developers, which would be now unfortunately nearly impossible. That's now all from me about this CD-4 speciality.
Dietrich

Dietrich
 
OK, when there would have been technical difficulties to store the full informations of the rear channels in the frequency area of about 30 kHz I would understand it, that there could only a storing of the difference signals. But I have never heard till now, that there was such a storage problem. So I have made this consideration, if not a more better channel separation has been possible. And I think, a real better technic needs not a full compatibilty. For example: CD's dont play on LP record players. Compact cassettes not on open reel recorder. But a full discreteCD-4 record, as I thought, could be played even on stereo LP players, of course with only the front informations. But I have never heard, that stereo listener have bought and listened CD-4 records. And I and many known Q-fans have never buyed a stereo record, when the same music from a band or artist could be received with a CD-4 record. Therefore is my consideration, that a compatibility for quadraphonic records (CD-4) has been superfluous. We are all angry about the result of " compatibilty" (and other mistakes by the industrty) which was not helpfull for a quadraphonic success. And I have now the interess to know, which considertions was done by the development of the quadraphonic technics - for example CD-4. But to have an answer for my idea, one should have the possiblity to ask one of the CD-4 developers, which would be now unfortunately nearly impossible. That's now all from me about this CD-4 speciality.
Dietrich

Dietrich

The requirement for stereo and mono compatibility hurt all the quad formats, no doubt - it almost always does, yet it still rears its ugly head, like in the early days of HDTV in the US, every company was promoting poorly performing, but compatible with existing television sets, HDTV systems - when the requirement for compatibility with NTSC was dropped, that freed engineers to develop something that performed better than would have otherwise been possible.

With quad, the record companies didn't want to bother with separate pressings for stereo and quad - and retailers preferred single inventory too - so the emphasis was on compatibility with the goal of everything being released only in quad at some point and those without quad setups would never notice or care. But, for the most part, it didn't work out that way.
 
Hello Disclord, I have thought to finsih the discussion here, before Lou Dorren will wonder, what other themes are to read on the Demodulator thread. But only last one: Although the quadraphonic records are all compatible to stereo, the record industry has made from 1971 till 1976 for each quadraphonic record (CD-4, SQ or QS) an additional stereo LP. Even for the full compatible Matrix records (the argument: The rear informations have by playing in the stereo mode varying positions in front as in the rear position!). All this together is for me the nonsense, which was produced by the industry. May be from other fans are more messages and opinions here. But for my I like to close my contribution, before Jon will stop us.

Dietrich
 
The way it was done guarantees an even sound from front to back. Had the back been only the subcarriers and the fronts had been only main audio, they would not have sounded the same. Instead of having good sound all around, the fronts would have sounded better than the backs. That would have been a source of annoyance for listeners, much more than less separation. In fact, I have recommended to back off on the separation a little bit to enhance fidelity by reducing the subcarriers slightly. It still sounds good and discrete.

The Quadfather
 
Unpacking a few things, I just ran across the bottle of Lou record cleaner and the wipes, but no instructions-could and would someone post them?
 
Unpacking a few things, I just ran across the bottle of Lou record cleaner and the wipes, but no instructions-could and would someone post them?

What was the ingredient in Lou's cleaner that made it let the needle scrape the gunk out of a records grooves? I've never seen anyone mention or talk about what it is. Does the bottle list the ingredients?
 
Unpacking a few things, I just ran across the bottle of Lou record cleaner and the wipes, but no instructions-could and would someone post them?

I have the instructions, but it is Copyrighted by Lou; so I don't think I should post it. I'll pm it to you; since you have a bottle.

- Ben
 
It has been my experience that CD-4 is not discrete. In fact, i have found better separation using SQ vinyl and the scripts on this forum. I now own 3 demodulators (JVC 4-DD5 , PANASONIC SE-405, and the great TECHNICS SH-400 ). And, with each one there is cross-talk from the front and rears. AUDIBLE cross-talk!! And, before someone here posts a reply regarding cartridge, stylus, and turntable used, let me also say this... I own 2 quad cartridges (AT-12Sa and the semi conductor Panasonic 450C-II ). I have found that the difference between using an eliptical versus shibata etc.. etc.. is pure rubbish. Although, the shibata clearly produces better fidelity - the cross-talk remains. So, I patiently await the new demodulator and I really hope that this unit will truly produce DISCRETE quad. DISCRETE as in reel-to-reel and Q8 sources reveal.
 
Only two asks to clear the problem: Which SQ decoder you use for the comparison CD-4/SQ? And which adjust records you have used by the adjustment of the demodulators(for excample those from JVC or technics)?

Dietrich
 
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