CD-4 Ramblings and Tech Discussion

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ndiamone

600 Club - QQ All-Star
Joined
Jun 13, 2008
Messages
658
Location
Silicon Valley (but I don't own it)
How about a CD-4 MODULATOR? We recently got the start of what we hope to be more funding and the pending cooperation of engineers who run the last DMM lathe housed in Southern California.

Yes. We want to cut new CD-4 DMM and press them on the 180G grainless red or blue audiophile vinyl and maybe even record at 33 for playback at 45 which during testing eliminated a lot of the bass contour problems while still retaining the headroom.

We found that out because of playing back a 15 IPS master on the low speed of a Muzak mastering deck which runs 11.25 and 22.5 IPS (instead of 15 and 30) and recording at 33 for playback at 45. So, 11.25 down from 15 IPS is 0.75 and 33 down from 45 is 0.740740740 etc, less than one cent of a semitone.

To be able to hear it in real time and align the mastering deck prior to setting it back up for 3/4 speed cutting, we use a old 92-C sync resolver from the film and television department.

We already have a few quadraphonic 15 IPS safety dubs rescued from various people's dumpsters for test-cutting with, people are working on trying to adapt a 3 DH Westrex cutterhead to house a diamond stylus and be able to cut into copper, that would make the 30KHz modulation center tone able to go down to 22.5KHz and still act as a constant-motion tone so the diamond doesn't get stuck in the copper and people are developing new vacuum systems so that we can cut deeper than a 50 or 60 uM groove without having the copper swarf get all entangled up in the works.

So all we need now is the new modulator.

Hey, people are funding the studies of the mating habits of exotic bugs, we should be able to get funding for this.
 
Alas, such funding would benefit humans and, as we all know, individuals meting out monies for various projects HATE human beings so I wouldn't be overly optimistic.

\:^)

Doug
 
It seems I remember someone was going to post schematics for an RCA quadralator CD-4 modulator. I don't recall what became of that.

The Quadfather
 
It seems I remember someone was going to post schematics for an RCA quadralator CD-4 modulator. I don't recall what became of that.

The Quadfather

Wasn't Greg Bogantz, the RCA Records engineer who developed their CD-4 "Quadulator" a QQ poster awhile back on that very topic? Might check the archives.
 
Yeah, that sounds about right, Didn't he say that he had one? I wonder if he could be persuaded to let it out on loan?

The Quadfather
 
Yeah, that sounds about right, Didn't he say that he had one? I wonder if he could be persuaded to let it out on loan?

Yes, Bogantz has the last surviving Quadulator, down there in the mountains of North Carolina, however a 1974 Quadulator with a 1974 design, 1974 circuitry and laying around unrestored and unused since 1974 would be completely useless for DMM or just about anybody else other than as a curiosity museum piece.

To match with the playback of Lou Dorren's new demodulator, we would need the reverse design as a new quadulator in order for this to work, not to mention his cutterhead improvements and re-designs for 3/4 speed cutting instead of the former half-speed or two-thirds-speed cutting previously required.
 
So, we are all operating 1974 vintage or thereabouts equipment. It performs quite well. A recapping and a tuneup will bring it up to par. Remember that they could spend much more on the modulator technology. there was no need to keep the unit cost down as with the demodulators. I don't imagine there is a whole lot of difference between 2/3 and 3/4 cutting speeds. Why not just run at the old speeds? After all, if it's the difference between not recording CD-4 and doing so. If the project was successful enough to warrant it, you could then design a new modulator. The Dorren demodulator is being built to work on the CD-4 standard. It's got to play what was recorded with that very modulator. That standard has not changed since 1974. If Lou decides to build a new modulator, it must conform to the same standards. The main difference between Lou's design and the old school demods is the FM limiter stages and the sharper (digital?) filtering. But there is nothing wrong with 1974 analog electronics technology, on the contrary, it was quite good. But on the other hand, I don't doubt that a new design could probably tighten things up a bit.

The Quadfather
P.S. if germanium transistors were used, all bets are off. but those were generally out of service by then.
 
So, we are all operating 1974 vintage or thereabouts equipment. It performs quite well.
A recapping and a tuneup will bring it up to par.

Up to par for CONSUMER tolerances yes, especially after having modern transistors and resistors and etc installed. Not for commercial or manufacturing tolerances. Remember the tolerances for consumer equipment and for playback are a LOT looser than those for commercial equipment or manufacturing.

Remember that they could spend much more on the modulator technology. there was no need to keep the unit cost down as with the demodulators.

It's like the Wonka-Vision Wonka Bar. So OK commercial and/or manufacturing gear don't have to be 100 times the size, just 100 times the quality so an ordinary person on the other end can experience it with ordinary (not even superior) quality (for that it would have to be 1000 times better).

I don't imagine there is a whole lot of difference between 2/3 and 3/4 cutting speeds.
Why not just run at the old speeds?

As everyone here knows, the very very first CD-4 titles produced were mastered at 11.11 RPM for playback at 33 because the cutterhead capabilities of the time were insufficient to be able to sustain a long constant reference tone without melting the bobbins in each channel of the cutterhead from overheating.

And if you find some of those early Princeton Labs test LP's, the sound quality was so terrible upon playback vs a 4-track tape modulated live to CD-4 and then demodulated live by the demodulaters that they almost didn't get the funding to proceed with re-tooling the cutterheads and cutter systems to work with 16 RPM.

The simple explanation for non-engineers of what they did for the ``live'' modulating and demodulating was basically tweak the 38 KHz center frequency subcarrier of two low-power FM Stereo transmitters down to 30 KHz, sent the front channels over the basebands of each one and then send the rear channels over the two subcarriers and reverse the process when connected to the demodulator.

Of course the actual explanation is, they used three subcarriers, one at 38 KHz for the stereo mixdown, one at 67 KHz, one at 76 KHz and one at 92 KHz, as they tried to introduce for FM Discrete Quadracasting. As we all know 19 KHz is only for the pilot tone that lights up the FM Stereo light on a receiver, 67 KHz is for Radio Reading Services for the Blind, 76 KHz is for subscription commercial music services and 92KHz is for hospitals, cable stations and other such installations where the transmission channel might be on 67 KHz for the transmitting station and the reverse direction might be 92 KHz on a second station transmitting from the receiving end for extended point-to-point or so-called narrowcasting applications before the advent of inexpensive data services.

So anyway back to the problems with Half Speed Mastering on Lacquer. 16 RPM cutting for playback at 33 has an ENORMOUS amount of bass-contour effect, not to mention, even tho the top end has the benefit of all that headroom, you still end up with a somewhat pinched and lifeless sound compared to the real-time mastering when you don't slam the cutterhead to its' limits and beyond like rock and roll is fond of doing.

The same effect can be heard when mastering, say a 78 RPM record at 45 RPM. Even with the correct size 2.7 - 3.0 mil stylus and a good cartridge, if a 78 is mastered at 45 for recording into the computer, all the natural life and ambiance of the original recording will be gone in the transfer.

Try it sometime. Of course, if you can find the same title mastered in both Stereo as well as CD-4 in addition to being mastered in a 45RPM SuperSonic audiophile edition, then that would be best.

But if you don't have that, and you don't have the 78 stylus and want to hear a slightly less pronounced effect of the same thing, play one of those audiophile SuperSonic classical music 45RPM discs from the 70's back at 33 and record into Adobe Audition using my tutorial here: http://bsnpubs.websitetoolbox.com/post?id=3024365 and then play the same record back at its' original 45RPM speed and record again and then compare the two.

Now do the same with some famous performance of a classical work that was recorded in both Stereo as well as CD-4. Record the stereo version at 33 into AA.3.0 or whatever using the same CD-4 stylus as a Quadradisc and then do the same to the CD-4 WITHOUT demodulating (even switching on the FM multiplex filter so you don't get carrier tone interference to make the test more equal) and you can PLAINLY hear what we're talking about.

Or just watch this video for a considerably more crude example: http://www.youtube.com/watch?v=oT8gmiCbuTI. By the number of raves on the post about the version transferred at 33 over the version transferred at 78, the number of deaf or partially deaf non-engineering listeners in the general public can be ascertained (looks over top of glasses).

Same as the transferred-at-78 version has more life, you'll notice conversely on your own tests that the real-time-mastered LP version has PLENTY of air and space where the CD-4 version does not, same as the 45 version has more air and space in real time than the 33 version, but NOT if you play the 45 back at 33 and resample digitally to 45 in the computer.

That's like some of the old early RCA Dynagroove cutting tests in the `60s where they were trying to save studio time by cutting stereo at 45 for playback at 33, taking the tape machines from 15 IPS up to 20-1/4 IPS, or worse yet, trying to cut a disc at 66-2/3 RPM. Actually it wasn't really 66-2/3, it was 56.35 since all they did was use what the ``78'' became when the ``33'' was set for 24, just like the Mattel doll people used 105, because that's what the 78 becomes when the 33 is set to 45.

Anyway, if you don't have one of these and want to hear what it sounded like, just take one of the old 16 RPM music discs cut in the 60's (either the 7-inch or the 12-inch), or see if that Lanny Kennedy is still a member here and see if he will sell his granddad's 16 RPM Will Kennedy Dancetime Orchestra records that has a 33 RPM counterpart, or take one of the 16 RPM Prestige Jazz series of double-albums on one disc, play it at it's normal 16 RPM playback speed and then take the same 33 LP album from the same period and play it back at it's native 33 RPM and see how you like it.

Or do what everybody else does with a 16 RPM title that has no 33 counterpart: Play it at 33, record it with Dolby NR onto a reel to reel deck at 15 IPS (or 7-1/2 if you don't have 15, or onto a Chrome or Metal cassette on a deck with a High Speed Dubbing setting if you don't have that) and then play the resulting tape back at it's normal speed with the Dolby out and the EQ setting to Normal instead of Chrome.

But watch out. Make sure you have the correct size playback stylus. The Prestige Jazz and most other mono 16-RPM 12-inch LPs from the late 50's and early 60's are cut with a one-mil mono stylus the same as most of the 7-inch 16's with the 45-size hole. The Will Kennedy and the other Stereo 16 RPM's were all cut with a normal 0.7 mil Stereo stylus, so no worries there.

Here's where it gets dicey: The 12-inch department-store 16 RPM's like Allied Artists and such are all recorded with a 0.5 HALF-MIL stylus, smaller than the Stereo stylus and commonly found on talking book players for the blind. Same holds true for the the seven-inch 16-RPM flexidiscs made by Auto-Com as well as the nine-inch Seeburg BMS 1000 discs with the 2-inch hole http://www.youtube.com/watch?v=bgo6u-qEECg. The guy in this video is the only one on YouTube who is not destroying his Seeburg disc on the first pass from playing it with a stylus that is too big for the groove.

The ones you REALLY have to watch out for though are the Highway Hi Fi records that went into `56 Chryslers. They have a very small 2 inch label on a 7-inch disc with a small hole, and were made from a 90 gram biscuit, same as for a normal non-Dynaflex ten-inch vinyl, but the grooves are a QUARTER-MIL, 2/3rds smaller than a stereo LP stylus and 75% smaller than a mono stylus. Playing a Highway Hi-Fi record with anything other than it's own stylus or a remanufactured one for a modern cartridge will be tantamount to playing an LP with a 78 stylus, destroying the disc on the first pass.

But all those have LP counterparts except for the demonstration discs with the announcers on them, and all those have already been transferred using compatible equipment, so there should be no need for transferring a Highway Hi-Fi record. If you find one, frame it and hang it up as art. Or Earl or Bill or...

But anyway, playing back a disc at slower than its' original speed will still sound pinched and lifeless the same as playing back a disc faster than the recorded speed because slow speed will dump the bass into the mud and the 2x speed of 66 over 33 or the 1.35 speed of 45 over 33 makes all the high frequencies move out of the range of the cutterhead and tape playback equipment.

The only reason it works the other way around, is that 11-1/4 IPS is 75% of 15 IPS (normal mastering tape speed) and 33-1/3 RPM is 74.0740740...% of 45, bringing the bass up out of the mud and leaving the treble in at least the same range of treble, just not as high, ergo 3/4 speed mastering is the magic threshhold. That, plus the difference between 74.074074074.... and 75, like the difference between the 45.00 RPM in the U.S. and the 45.45 RPM at which European discs are cut is negligible.

The half-speed-mastered version sucks all the air and space out, along with most of the life and vibrancy carried thereby. It's the same with the standard stereo Half-Speed-Mastered LPs by Columbia or whoever. And that you can't do anything about, it's endemic to the process. On rock-and-roll, there's not much air and space there to begin with, so, say CD-4 Black Sabbath for example, you'd probably never be able to tell the difference.

Now, the inbetween version of that was the 2/3rds speed cutting, more or less 22 1/2 RPM for playback at 33. The first of these was of course Japanese since they had half-speed-mastering lathes for all their CD-4 45 RPM calibration discs with various quadraphonic Muzak titles on the back. So, they improved their cutterhead and modulation electronics once again to be able to cut at roughly 2/3rds speed.

Guess what? Most of the air and space was back, most of the bass contour effect was gone and most of the pinched effect in the treble was gone. Why did it not catch on? Because they didn't do it until the end of 1976, by Spring of 1977 with a few exceptions, most of the last CD-4 titles had already been cut, places like JVC Hollywood were going back to stereo cutting and by the end of 1977 a year later, quad in ALL formats was pretty much a done thing.

Now the 3/4 speed cutting i.e cutting at 25 RPM for playback at 33 would reduce those artifacts even further, but cutting at 33 for playback at 45 would eliminate those artifacts altogether, and then 33 RPM lathes are a lot easier to come by than 25 RPM, and then the RIAA recording curve could more easily have its' bands lowered to work with 3/4 speed cutting a lot easier than trying to adapt a lathe for 25 RPM besides lowering the RIAA curve, not to mention the better sonic response recording at 33.

Cutting onto DMM would be the only way to go as well, because now, at 45 RPM playback speed, your original 23 minute LP lacquer side at 33-RPM now has to be 23 minutes at 45 or 30 minutes at 33. The only way you'd be able to master that with any kind of decent groove depth and decent volume is on a DMM, since not only does it cut longer sides than a lacquer at the same volume, but it also has a greater range in the treble. What ends up as a brittle-sounding top end in real-time DMM cutting maybe just what the CD-4 process needs at 3/4 speed cutting,at 33 for playback at 45 we'll have to see.

You never know. They could have had exactly what they needed if they'd have waited a few years for the SX-84 DMM heads to come out for the VMS-80 or VMS-82 Neumann lathes for BOTH matrix as WELL as discrete-disc cutting. By then they could have had 5.1 or even 7.1 utilizing both matrix and discrete technologies at the same time like the 1969 test disc uses SQ laid over QS laid over EV laid over DY to create some crazy kind of 12-channel or 14-channel matrix presentation.

I have the test LP and the film to which it syncs around here someplace. It's been years since I played it for anybody, but I imagine even if somebody HAD a matrix decoder that could retrieve 12 different kinds of phase differences all at the same time, even with 21st century digital steering logic, I doubt very seriously an all-matrix 12- or 14-channel program would have got off the ground.

But, I imagine, using a simple 90-plus and 90-minus matrix, i.e. splitting the 180-degree out-of-phase between the two channels and then introducing the signal from a retooled London Box originally designed by Ben Bauer to give a discrete rear-center and then using the CD-4 (or in this case UD-4) to isolate certain tracks or instruments, I think once we got all the kinks worked out it would work fine.

After all, if it's the difference between not recording CD-4 and doing so. If the project was successful enough to warrant it, you could then design a new modulator.

Only one problem behind that, though, back to the Willy Wonka bar on the Wonka-Vision example.
The only reason we'd even GET funding in the FIRST place for even TRYING is if it would:
A) eliminate the bass contour effect,
B) restore the air and space, and
C) take away the pinched effect on the treble that plagued the original recordings.

If a huge company like RCA using people at the influential Princeton Labs came This Close to not getting CD-4 approved in the first place because they could only cut at eleven RPM, (like they came This Close to not getting CED Videodiscs approved because they could only cut at 45 RPM [1/10th speed]) and came This Close to got getting the green light after they perfected CD-4 cutting for 16 RPM, a year later, then we as a little bitty research group with no ties to like the Government's Lawrence Berkeley Labs or any huge corporation like RCA with its' own Princeton research lab and much of its' own funding, well, we'll have to do a LOT better than RCA or the LBL research teams JUST to get testing approved, nevermind going ahead with manufacturing.

The Dorren demodulator is being built to work (the best) on the (original) CD-4 standard. It's got to play what was recorded with that very modulator. That standard has not changed since 1974. If Lou decides to build a new modulator, it must conform to the same standards.

Same standards, yes, same parameters, yes. Same design, no. There's a lot better ways today of both creating as well as retrieving CD-4 signals, just as in the modern day there are a lot better ways of retrieving magnetically recorded signals from the legacy media formats which contain them.

The main difference between Lou's design and the old school demods is the FM limiter stages and the sharper (digital?) filtering.

Which in the opinion of this as well as several other engineers is a major, major improvement. Utilizing the design of the original CD-4 process notwithstanding, this is up there with the conversion from 11 RPM cutting and 16 RPM cutting, or even better, from 16 RPM cutting to
22 1/2 RPM cutting. So, it's NOT the same animal.

But there is nothing wrong with 1974 analog electronics
technology, on the contrary, it was quite good.

Well, we also want to have as much of it be valve-design oriented as possible. If there could be a such thing as a valve-design CD-4 modulator---or even demodulator that was only digital in the places it ABSOLUTELY needed to be, then that would even be better.

The reason we're trying for that is we're going off of the valve-design DMM cutting
test discs that never got off the ground.

When RCA, Mercury and Columbia were mastering their Living Stereo Living Presence and Legacy Masterworks for their Anniversary Reissue audiophile CD's, done in the late 80's and early 90's, they were going back to the original 3-track half-inch work parts (unedited session masters) for the first time since the original stereo LP mixdowns were made in the `50's and `60's.

They'd align each one up individually on the playback deck in order to transfer each to digital so that it could be tuned up in a new post-production session and prepared for the final CD release, but inbetween time,they cut DMM ref copies of each tape they aligned through what, according the slip inside the test pressings we have, were identified as Gotham Audio valve amplifiers. Even compared to the CD's that came out, the DMM test pressings cut with a valve amplifier sound
F A B U L O U S.

So we can imagine how terrific a new CD-4 record would sound if
A) it was mastered at 25 RPM for playback at 33 or better yet 33 for 45
B) sent through a newly redesigned Quadulator (hybrid valve/digital)
C) mastered through a valve amplifier
D) onto DMM and
E) pressed onto 180G grainless red or blue dye

And if you wanted to know why they invented DMM to begin with it wasn't for better fidelity.
RCA invented DMM for cutting CED videodiscs with way back in 1979 and then gave it to Neumann/Teldec in trade for some circuitry they had invented and couldn't figure out what to do with that RCA thought would work well with some CED improvements before LaserDisc took over the videodisc market.

Then Telcec and Neumann perfected DMM and then tried to SELL it back to RCA for something they GAVE AWAY, so if you run into some legacy RCA mastering engineers who have a decidedly negative opinion about DMM and wondered why they never got their own DMM lathe and farmed everything out, now you know.

But really, DMM was invented because skinny engineers were becoming the norm and they didn't have the body insulation we did (in the form of 3X shirts and 54 waist pants or whatever) for cutting 10 and 12 hours a day in a 55-degree room to preserve the lacquers from groove bounce-back before we could get them into refrigerators. Guys wanted heat in the mastering room and the only way to do that was change the cold and hard from the room temp to the cold copper and the hard diamonds with which to cut.

Go to the library and look up photos of old mastering engineers from the bygone eras.
There's enough spare tires in the room to outfit a fleet of 18-wheelers for a lifetime.

But on the other hand, I don't doubt that a new design
could probably tighten things up a bit.

Absolutely. Which is exactly the point.

If germanium transistors were used, all bets are off.
But those were generally out of service by then.

So, once again, professional and manufacturing gear has to be a number of degrees better than its' consumer counterpart, therefore whoever redesigns the new modulator would have to use germanium transistors then for the very reason you mentioned.

So maybe when all is said and done, we might be able to cut CD-4 DMM at 33 for playback at 45 with a brand new modulator with a brand new design and blow the lid off the audiophile vinyl market.

Your homework for next time is Chapters 8, 11 and 13, pages 135-151 in your workbook, and show up at 5 to setup for the sessions Friday and Saturday night with a downbeat promptly at 8. Standard four-hour Union Scale sessions, musicians get to go home at 12, depending on how fast you strike, you MIGHT get out of here by the time the sun comes up.

Failure to show up will GUARANTEE you at LEAST a one-grade penalty on the next exam and maybe more depending on how the session went and what kind of mood I'm in afterward when I grade everybody's performance.

Class dismissed. See you Friday night at 5 (looks over top of glasses).
 
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This will ramble a bit.
OK, so you're going for a superior product than the legacy CD-4 recordings, but you want to do it in the analog realm. The reason I mentioned germanium transistors is that they are known to be leaky, noisy and inferior. I am not suggesting that they should be used, rather than if the original Quadulator used germanium transistors, it should be scrapped. Would you really use germanium transistors? Where would you get them? I think that for a new design, vacuum tubes would be preferable to using germanium, but I expect that excellent results could be obtained using common silicon semiconductors.

I don't doubt that Lou's design for a demod will be an improvement, otherwise, why do it? I'm on the buy list. Interesting about the cold room conditions and the phat engineers. It doesn't seem like cutting on copper could be done quietly. But then, I'm obviously not a lathe troll, so I'm learning. (I found your secret website).

So, you would want to shoot for a playback speed of 45 RPM. Hmmm, very interesting. All other things being the same, if you used the wasted space that exists on CD-4 records, is that how you would recover your playing time? Also what is DMM? Would you use a vacuum tube amp for the cutter head?

OK, Now my interest is piqued. My ears are drooling! Is there a chance that this could actually happen? So whose funding are you talking about, the industry, the government? I suspect that if it isn't someone's labor of love, like the Lou Dorren demod, it will probably not happen. But we are still waiting for the Dorren demod.

The Quadfather
 
This will ramble a bit.
Not near as long as mine just above (WINK)
OK, so you're going for (more of a) a superior product than the (original) legacy CD-4 recordings, but you want to do it in the analog realm.
If we can, yeah, we'd like to be able to marry all kinds of technologies heretofore not able to be combined just to see if it would have worked back in the day if the timing would have been right.
The reason I mentioned germanium transistors is that they are known to be leaky, noisy and inferior. I am not suggesting that they should be used, rather than if the original Quadulator used germanium transistors, it should be scrapped.
Ah. Well, that was a little before my engineering time, but I guess a lot of legacy engineers favored them for one reason or the other. I was at the Bay Area Electronic Swapmeet this past Saturday and brought up the topic to all the legacy engineers there and had to listen to a three hour waxing-enthusiastic by all kinds of guys.
Would you really use germanium transistors?
Dunno, like I said a lot of legacy engineers seem to think they have a lot going for them. If they are leaky and/or noisy, maybe that's why they were discontinued and these so-called `titanium-eared' guys maybe need to pull....well nevermind.
Where would you get them?
I always thought the Russians or Chinese could come up with anything, being for example they're the last place where one can buy valves for a valve amplifier.
I think that for a new design, vacuum tubes would be preferable to using germanium, but I expect that excellent results could be obtained using common silicon semiconductors.
Probably so, but again, this is just as much about marrying completely unrelated technologies into a manageable whole as it is about resurrecting a legacy format for the audiophiles. I figure if John French formerly head designer and chief engineer at Ampex can get away with 8 tracks on an analog 2 inch (track 24 is left where it normally is for an isolated sync track) and have it run by valve amps besides, I figure this one can't be THAT hard.
I don't doubt that Lou's design for a demod will be an improvement, otherwise, why do it?
I'm on the buy list.
If I could afford $500 for a setup with one cartridge or $750 for a setup with a spare cartridge, not only would I be buying one for my own library of CD-4 recordings, I'd be stocking the transfer labs which line the hallways as well with setups just like it.
Interesting about the cold room conditions and the phat engineers.
Well some of that is just endemic to running a lot of electronics in the same room at the same time, being modern-day computer labs are pretty much the same.

But the rest, of the reasons for the cold room like I said is 1. to make the swarf easier for the cutterhead vaccuums to pick up, and 2. to preserve the lacquer from having its' freshly-cut grooves from partially collapsing back in on themselves, (especially during fast attacks) between the time it leaves the lathe and the time it takes to get downstairs to the refrigerators. If you leave a lacquer out too long, the resulting record will sound a little drained and/or muffled.

It doesn't seem like cutting on copper could be done quietly.
Well, as we all know DMM requires a diamond stylus with a supersonic frequency applied to it in order to avoid getting snagged up in the copper. We figured the CD-4 tone could be added in place of the stylus cutting frequency and be able to kill two birds with one stone. But apart from the chatter induced thereby, the heated cutting tool minimizes most acoustic noise during the cutting process.

But then, I'm obviously not a lathe troll, so I'm learning. (I found your secret website).
Being as young as I was when I started in this field, the only way I've ever been able to be taken seriously all these years by any engineer that could actually do anything is to pretend to be my first recording professor back in middle school as well as myself. Being a kid in his 20's, Steve Espinola the board owner over there couldn't understand the reasoning behind it.

So he threw me off the Lathe Trollers board 1. for knowing too much about too many obscure things 2. for having to pretend to be myself as well as my first recording professor back in middle school and 3. because the guy that owns the website over there is a kid in his 20's and can't understand how one guy's knowledge can be so broad in the legacy media format field.

If Steve wants to email me and invite me back and apologize OK. My email address is the same as it always was. He knows how to get ahold of me. Otherwise you guys and the BSNpubs stereo chat guys and the gramophone gang and etc. can benefit from my Wiz-Dom. (Doncha carry nothin' that might Be a load c'mon ease on down, ease on down, down the ro-oad bah dah bop.)

Like this one:http://78rpmrecord.com/altformat.htm I wrote that (except for the title) in middle school in place of the exams before Christmas, for the charter academy I attended at the time, submitted it to the 78 RPM website like nine times as myself and they wouldn't take it til I sent in this whole scenario about how I learned all this stuff off of the recording professor and the staff at what was once known as Edison-Armstrong-Marconi Charter Academy in upstate Michigan.

So, I turn it back in as him, talking about how ``one of my students (me) wrote this back in the 5th grade in place of a midterm exam'' and poof went right up.

And if you want to know how I got my handle, yes my first recording professor was named
di Amone (Italian) but his first name was Andrew. I always thought that was too plain-sounding so I switched the E and the A being I'm dyslectic anyway like most engineers and then invented this whole scenario about his sister in the art department being named Startdemusic Diamone. You know.
Endraw works in the music department and Startdemusic works in the art department?

You hadda be there. It was funny at the time, though. Trust me.

And the OTHER way I got my handle is I've always been in the sound department at wherever, school, church, boy scouts etc. and as we all know the four basic types of production elements for sound is Narration, Dialogue Music and Effects, or N,D, M&E.
Say it real fast it comes out ``ndiamone''.

So, you would want to shoot for a playback speed of 45 RPM. Hmmm, very interesting.
It's the only way we can think of to not have the bass be in the mud and the treble end up brittle. Yeah the 25 RPM mastered CD-4 LP's near the end of the CD-4 era are pretty good, but still, it was recorded at 25, so even with the master tape running at 11-1/4, it's still being originally recorded at 25 and not 33.

That's like the difference between a regular live-in-the-studio recording being done at 15 IPS and one done at 11-1/4 IPS. The 11-1/4 IPS recording treble is not going to be as transient and the bass is not going to be as tight. So, recording at the normal 33 RPM at LEAST we'd get the SAME fidelity as a normal 33 intended for 33 playback, and, depending on how it all plays out, hopefully do better than that with a 33 cut for 45 playback,

And talking about reducing the carrier wave pickup problem near the center of the disc as well as saving space thereon, I wanted to use the Constant Linear Velocity format used by portable dictation formats of the early 50's like the Grey Audograph you can read about here:http://www.std.org/russ/ReinventingTheGrayAudograph.html and see one here: http://www.youtube.com/watch?v=wyM0H11-rjs

But everybody else just looked at me like I was from some other galaxy long long ago and just joked about my ``great adventure'' trying to take place.

Apart from the fact that for CLV you can't have variable pitch, how would you adapt the millions of normal Constant Angular Velocity outside-in turntables in existence to play inside-out CLV records? Re-make the old Lenco 75 turntables http://www.youtube.com/watch?v=dQs_cTXZlNI and install a mechanism for a lead screw to drive the puck gradually from center to edge? It's the only turntable I can think of where you could modify it to play both normal CAV records as well as CLV.

Oh, and P.S. The reason you can't get a decent sound with a regular stylus on a regular turntable playing a Grey Audograph or its other related CLV disc format CGS/Memovox is, both of those are not cut into the disc with a swarf being removed, but rather embossed onto the disc like the Fairchild aluminum discs in the `30's http://www.youtube.com/watch?v=0ztBTF6M720&playnext=1&list=PL0A563AC5AA067CBB which technically was the first DMM.

So, not only do you have to have the right shape stylus to play these (half-V i.e. ``I/'' shaped groove, one wall straight up and down and the other wall angled out like a V, or in the case of a Memovox, a doorknob-shaped stylus similar to a vertical-cut Pathe) but you also have to have the tonearm driven by a lead screw like an Edison cylinder or disc because the grooves are too shallow to be able to carry the weight of a tonearm by itself.

We now return you to your regularly-scheduled program about our CD-4 experiments.

The original experiment results of course weren't like it would have been if we'd used a real Quadulator anyway and tweaked it up from 15 KHz center frequency up to 22-1/2KHz and did our 3/4 speed mastering like that.

Instead, we used what we had handy, stringing up this raggedya** homemade modulator made up from two old valve-style FM-Stereo broadcasting modulators we got that were leftover from a radio station when they went to solid state, and then we had the engineers tweak the center carrier frequency down from 38 to 22.5 and then cut with that at 24 RPM with a 3B stereo cutterhead leftover from the Library for the Blind on this raggedy old strange-speed 24-RPM talking book lathe from the `30's that they used when normal talking books were still 33 before intelligible fidelity could be had at 16.

Of course, the ability to engrave the carrier wave onto the disc with something as cheezed up as that was RIDICULOUSLY low, like minus 20 dB or minus 25 dB but it was enough to get a minimal pickup and minimal demodulation over.

But the old 11 RPM RCA Princeton CD-4 test LP's from the early 70's, sounded a LOT worse both in stereo as well as quad, and had a carrier wave level below minus 30 dB besides. Even with the low level of carrier wave able to be modulated onto the disc, this one of ours also sounded noticeably better than the vast majority of half-speed-mastered CD-4 titles from JVC - Hollywood as well and sounded about the same as the classical test pressings mastered at 25 RPM near the end of the CD-4 era.

So we figure if we can do a better carrier wave with this cheezed-out raggedya** old setup than the real engineers with real gear did with the first RCA - Princeton tests, and we can do almost as good hanging a 3B unmodified cutterhead from the `50's, onto a raggedy old 24-RPM talking book lathe from the 30's cutting onto a lacquer, then we figure with a normal modern lathe, a normal modern cutterhead and then adding the DMM to the mix it would work cutting at 33 for a 45 playback and also allow for 30 minute sides at 33, meaning 23 minutes a side at 45.

All other things being the same, if you used the wasted space that exists on CD-4 records, is that how you would recover your playing time?

If by ``wasted space'' you mean the excessively tight pitch with which a great number of CD-4 records were cut, then the answer is Yes.

I suppose they did that because as we all know, the fidelity nearest the edge of the disc is considerably greater than that nearer the center due to the increased linear speed at the edge. That's one of the reasons Cook Binaural Stereo never took off, because the track nearer the center had to be recorded with a 500 Hz crossover.

But if you're curious, you can read all about that on my blogs elsewhere on the Web talking about all the various incarnations THAT went through before they settled on two tracks side by side by each other, one near the edge and one starting halfway through and going to the center.

Probably the mastering engineers of the period figured the tradeoff on the tight pitch would be recovered by having the material closer to the edge of the disc, probably allowing for a cleaner pickup and demodulation of the CD-4 carrier tone at a time when carrier wave pickup on a disc was mediocre at best.

However, as technology and mastering techniques improved towards the end of the CD-4 era, many discs were cut with standard pitch and left no ``wasted space'' in the center. And they even did 135 gram pressings too. I have an RCA Special Products black-label with the dog on the side copy of Elvis Aloha from Hawaii that makes no mention of CD-4 on the disc or the jacket, except in the dead wax you see the quadraphonic catalog number and of course the CD-4 rainbows dance in the light.

But it's on standard 135 gram vinyl like they used to use in the `60's vs the 70 or 90 gram vinyl common throughout the `70's. This copy goes all the way to the center compared to the ubiquitous 70 or 90 gram orange label copies you find all over that leave a couple inches at the end. It was mastered with nice, deep grooves as well, better than a lot of stereo copies of the same period,

When played through a Stanton 681S or 780DQ with Shibata stylus, even through my unrestored JVC-CD4-50 it still sounds F A B U L O U S compared to regular copies.

Also what is DMM?
Direct to Metal Mastering. http://totalsonicmastering.com/dmm.htm

Effectively a DMM engraves onto the mother, from which stampers are then made for the record press, thereby eliminating the first two steps of lacquer master, silver plating that, electroplating nickel onto that to make a negative mold, and then electroplating THAT to make a POSITIVE mold from which stampers are then made.

Depending on who you talk to, some guys say that being a living organism, cutting on a nitrocellulose acetate lacquer is akin to recording through valve equipment vs. solid state, and brings a certain warmth to the music. Other guys say bypassing the first two steps with DMM either brings the presence of the original mastering more up front, or else from metal having never had a life, shatters it into a million pieces from the brittleness of the treble that results, same as what happened to first-generation CD's when people complained you could hear breathing and coughing and chairs scraping and air conditioning and etc. But we figure that brittleness when mastered real-time at 33 would warm up quite nicely when cut at 33 for playback at 45.

Would you use a vacuum tube amp for the cutter head?
Sure, love to if we could find the original Whitepapers of the guys who were trying out the DMM experiments in the late 80's and early 90's with the classic RCA Living Stereo type programs so we could figure out what we were doing and why their experiments never got off the ground.
OK, Now my interest is piqued. My ears are drooling!
Is there a chance that this could actually happen?
Sure. But like any other kind of commercially non-viable art, this needs patrons the same as any other legacy media format restoration or re-creation. You know what they say: If you create for the masses you eat with the classes, and if you create for the classes, you eat with the masses (if at all).

Like, other than the new Cheap Trick album, how many other modern 8-tracks can you name? Surprisingly, 8-track-only issues number in the hundreds IN TWO THOUSAND AND ELEVEN!!
So whose funding are you talking about, the industry, the government?
Anybody's we can get that won't be more of a problem than it's worth in man hours to keep track of the accounting or being interfered with while engineering the project by the grantors.
I suspect that if it isn't someone's labor of love, like the Lou Dorren demod, it will probably not happen.
Well as we all know, labor of love or not, very very few guys with the time, knowledge, energy and money all in the same place at the same time are going to be able to assemble enough of a staff who are also in possession of the necessary time, knowledge, energy and money to get it off the ground.

GZ (pronounced Gay-Zed) can cut it at 45 if we get them a modulator, the valve amps and the 11-1/4 IPS Muzak tape deck with the 4-track heads you would need. Then once it was there, you'd need to align the 11-1/4 IPS deck, and where are you gonna find an STL tape for Muzak format. But, the people who have all THOSE things need to be paid for THEIR work as well, since neither of these guys have the necessary etc. etc. etc either.

And then they could still use the special setup to cut the reproductions of the 16-RPM Seeburg 1000 BMS discs that we want to cut as well, just without the modulation and cutting real-time at 16 RPM onto DMM For that, we want to press up colored vinyl that matched the original label colors of each series so nobody could put `em up on eBay as ``original'' and have everybody not know the difference.

But we are still waiting for the Dorren demod.
See above under ``everybody does not have the necessary time, knowledge energy and money all in the same place at the same time.''
 
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Interesting what you said about modifying a FM stereo modulator for a test. I saved an Orban Optimod TV from our TV station when we went digital with such a project in mind. It would require a second one, which I failed to obtain. It seems that the engineers at competing stations viewed it as an opportunity to make money, money I didn't have for a project that:
1. might not work
2. I might never get the time to implement
3. Even if I did, I probably couldn't get it into the hands of an interested record troll
4. My idea of what would be needed to make it work would be tainted by my inexperience in the record cutting field.
The orban I thought would make a good platform, because it has the system broken up into removable cards that could be replaced with homemade cards. It is essentially similar to CD-4 except for it uses DBX instead of ANRS.

That's all for now, gotta go.
The Quadfather
 
Interesting what you said about modifying a FM stereo modulator for a test. I saved an Orban Optimod TV from our TV station when we went digital with such a project in mind.....It is essentially similar to CD-4 except for it uses DBX instead of ANRS.

Which is another whole topic all by itself.

DBX LP's we might be able to incorporate into this as well since CX for LaserDisc is so inferior.
But then, how would that work? DBX-encoded 45-RPM CD-4 DMM LP's would probably get rid of the rest of the bass contour problem even cutting at 33 for playback at 45, but then how would that cut into the playing time?

Normal lacquer-cut 33 RPM stereo DBX-LPs were always down around the 15-18 minute per side mark when normal LPs were 23-25 mins/side. This would basically reduce down to 10-13 minutes a side at 45, maybe that could be bumped back up to the original 15-18 mins of a 33 with the DMM system, but then cutting at 33 for 45 playback, you'd be back to how it is now: one LP takes up a two, three or four disc set on 45 audiophile.

....I probably couldn't get it into the hands of an interested record troll...
Well you got one out of four now....
 
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Yeah, I see that. And that's one of the bigger problems on that list. But I still would need another Optimod TV stereo generator, and I would have to design an ANRS card to operate at 3/4 speed. Since no CD-4 demod including Lou's is capable of using DBX, you would have to replace the DBX circuitry with ANRS circuitry, set up for the cutting speed, unless you could cut in real time. It seems like the subcarrier modulation method is different also. As I recall, they used AM instead of FM/PM for the subcarrier.
The Quadfather
 
But I still would need another Optimod TV stereo generator...
eBay? Your local ham radio/vintage electronics swapmeet that meets on the weekends once a month at the local junior college?

... and have to design an ANRS card to operate at 3/4 speed since no CD-4 demod including Lou's is capable of using DBX....
Or design a new one for BOTH dbx for mastering the new 45-RPM DMM CD-4's as well as the original ANRS so it could play back the existing legacy media being you'd have to design a 3/4 speed RIAA curve encoder anyway.

It seems like the subcarrier modulation ...used AM instead of FM/PM IIRC.
Dunno, gotta talk to a design engineer on that one. And speaking of which, probably all this talk by an operations engineer like me and a basement hobbyist like you is probably just annoying to all the design and application engineers.
 
Originally Posted by The Quadfather
It seems like the subcarrier modulation ...used AM instead of FM/PM IIRC.
Reply from ndiamone
Dunno, gotta talk to a design engineer on that one.

BTSC Zenith/dbx system Stereo TV used an AM L-R subcarrier and special form of dbx for noise reduction, unlike CD-4 that used FM-PM-FM for the difference carriers with ANRS (which JVC ended up paying Dolby patent royalties for). And although everyone including JVC called the CD-4 difference signals "subcarriers", they technically were not because there was no 'main' carrier for them to be a 'subcarrier' of.
 
Ndiamone wrote:
...since CX for LaserDisc is so inferior.

CX for LD was heavily modified from the LP version - and the LP version had as its goal non-audibility - in other words, non-decoded, you wouldn't hear the noise reduction modulating the signal and there was no spectral emphasis like Dolby or DBX to cause frequency response changes. CBS wanted to maintain a totally compatible noise reduction system. That's why Pioneer and RCA selected it for their videodisc systems. But Pioneer reduced the noise reduction from 20 to 14 db to increase compatibility and also raised the breakpoint where the compressor went from a 2:1 slope to a 1:1 slope from -40db to -28db and changed the control path filter from 100Hz to 500Hz to better protect against low-frequency NR modulation. So CX-20 for LP and CX-14 for LD were not compatible at all. RCA needed so much NR on the CED disc that they kept CX-20 as-is, with no changes, using the full 20 db of NR.

Dolby submitted Dolby-C and DBX submitted dbx-II for testing by Pioneer when they were shopping for an NR system, but both Dolby-C and dbx-II significantly changed the sound for listeners without a decoder, which CX did not, and that's how CX ended up on LD.
 
BTSC Zenith/dbx system Stereo TV used an AM L-R subcarrier and special form of dbx for noise reduction, unlike CD-4 that used FM-PM-FM for the difference carriers with ANRS (which JVC ended up paying Dolby patent royalties for).
So does that mean a person could or could not use either straight dbx or Zenith dbx in place of the Dolby-based ANRS in a modern CD-4/UD-4 modulator?
And although everyone including JVC called the CD-4 difference signals "subcarriers", they technically were not because there was no 'main' carrier for them to be a 'subcarrier' of.
Unless you go on the assumption that the ``normal carrier'' to which the ``subcarriers'' are attached so to speak is the regular record that's used for the front/sum channels being it's in the normal audio frequency range. But then I suppose you'd have to call it a super-carrier instead of a subcarrier since it's above the range of human hearing, not below (like automatic cue tones for audio-visual gear)
CX for LD was heavily modified from the LP version - and the LP version had as its goal non-audibility - in other words, non-decoded, you wouldn't hear the noise reduction modulating the signal and there was no spectral emphasis like Dolby or DBX to cause frequency response changes. CBS wanted to maintain a totally compatible noise reduction system. That's why Pioneer and RCA selected it for their videodisc systems.
I just know that my uncle was working at Columbia NY for a couple years when the Greatest Hits of 17?? series came out and they cut a demo of GH of 1720 with the straight version on one side and the CX version on the other side. Then they had another demo where the opening track on Side 1 was first recorded straight then with CX and on side 2 the reverse, CX first, straight version second.

Granted the CX version WITH DECODING sounded better (but not without), the grooves on the encoded side were cut very deep like an SQ record compared to the straight versions, (which is how I ran across it and the reason I kept it) whether they be on the disc with one kind on one side and one kind on the other, or whether it was on the disc that intermixed the types. I'm sure there's plenty of copies of both those demos still out there that could be found in thrift shops and swapmeets so people could play them next to each other and A/B them.
Both Dolby-C and dbx-II significantly changed the sound for listeners without a decoder, which CX did not.
Well then my old Magnetic Video LD copy of The Moon is Blue must have some mastering issues then, because without the CX it sounds T E R R I B L E. Shrill and brittle and then has the hiss of the optical sound print from which they mastered in the first place in addition to the hiss of the 2 inch broadcast master onto which they recorded it in the second place, and then the hiss from the FM carrier analog sound system in the third place. With the CX on, it still sounds bad, just most of the hiss is gone and it's not so brittle-sounding. But all my old MVC Fox Musicals series (Hello Dolly, Sound of Music etc) are all the same, so dunno if it's just endemic to the format or not.
 
So does that mean a person could or could not use either straight dbx or Zenith dbx in place of the Dolby-based ANRS in a modern CD-4/UD-4 modulator?

No, because the CD-4 decoder would be expecting the 2-band JVC ANRS for the difference signal subcarrier and if it doesn't track the difference signal on the LP, the f-b separation will not be correct at all because and it won't de-matrix the F-B signals correctly. Now if a demodulator were made with dbx-II NR for the subcarriers and then a CD-4 cut with dbx-II encoded subcarriers (and if the main signal were dbx encoded too), you'd end up with a perfectly silent CD-4 LP with almost perfect separation because dbx-II doesn't need any level calibration like ANRS or Dolby systems do for correct decoding and the sum+subcarrier would de-matrix basically perfectly.

BTW, the dbx used in Zenith's BTSC system was a level-dependent system, like the Dolby NR systems, due to the fact that it had a kind of level-sensitive variable premphasis in addition to linear 2:1 companding. It was like a mix of dbx and Dolby (Dolby tried to sue and lost). Mark Davis, the main inventor of AC-3, was the inventor of the dbx-TV NR system. He moved to Dolby shortly after that.
Anyway, early BTSC decoders had almost no stereo separation because companies were not setting the levels correctly for the dbx decoding, leading to incorrect dematrixing of the sum+difference channels. I recall a review in Video Magazine of an RCA Stereo TV that had 3db stereo separation! DBX began a crackdown on companies and we finally got NTSC stereo TV with proper 20db of channel separation.

As a side-note, JVC tried to get around paying Dolby patent royalties for ANRS with their Super ANRS system, but it didn't work and they had to pay. JVC then modified the original ANRS used for tape decks to make it semi-compatible with Dolby-B system - they sold more tape decks that way. Sony had to pay royalties to Dolby too for their ATRAC data compression system used in MiniDisc and SDDS - they infringed on Dolby's AC-2 and AC-3 patents. Of course, that's when Dolby was a 'real' company that did original research and didn't just buy inventions from others and market them with the Dolby name slapped on.


Well then my old Magnetic Video LD copy of The Moon is Blue must have some mastering issues then, because without the CX it sounds T E R R I B L E. Shrill and brittle and then has the hiss of the optical sound print from which they mastered in the first place in addition to the hiss of the 2 inch broadcast master onto which they recorded it in the second place, and then the hiss from the FM carrier analog sound system in the third place. With the CX on, it still sounds bad, just most of the hiss is gone and it's not so brittle-sounding. But all my old MVC Fox Musicals series (Hello Dolly, Sound of Music etc) are all the same, so dunno if it's just endemic to the format or not.

The Mag Vid LD of "The Moon Is Blue" was not encoded with CX - it's never been released with CX encoding so playing it with CX decoding will get you nothing but pumping and garbage for sound. BTW, the 2-inch master used for ALL early LD's, including DiscoVision, was the IVC-9000 system, not Quadraplex as many people think. Later, 1-inch C-Type was implemented by Pioneer.

CX has no frequency selective companding, like Dolby systems do, so it won't 'tame' harsh sounding masters - it reduces the noise added by the FM analog carriers and allows an expansion of the FM modulation from 100kHz to 150kHz to allow more headroom. It also reduces or eliminates audio "Helicoptering" due to defective pressings. There's a paper on my website called "The Audio Side of LaserDisc" that outlines both LD FM encoding and the CX process for LD.http://issuu.com/disclord/docs/the_a...adger?mode=a_p The early LD's could sound quite brittle due to the mastering formats used - MCA DiscoVision used interlocked 1/4-inch tape for the audio on their stereo releases and it still sounded bad due to the encoding system not being totally perfected yet - and the FM audio carriers are too close to the video carrier, especially with high audio levels and high chroma at the same time. CX helped with this, along with better filtering during mastering as Pioneer perfected the system.
 
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BTW, the 2-inch master used for ALL early LD's, including DiscoVision, was the IVC-9000 system, not Quadraplex as many people think.
Later, 1-inch C-Type was implemented by Pioneer.
Which would make sense because we inherited a lot of early 2 inch LaserDisc masters that hadn't been drilled through yet and all we had at the cable station I worked at was a 2 inch helical machine we had given to us by SelecTV (an early single-channel pay TV system like OnTV, which scrambled the signals of a UHF station at night and on the weekends. Most of those are all Spanish stations now.)
No, because the... f-b separation will not be correct at all...and it won't de-matrix the F-B signals correctly. Now if a demodulator were made with dbx-II NR for the subcarriers and then a CD-4 cut with dbx-II encoded subcarriers (and if the main signal were dbx encoded too), you'd end up with a perfectly silent CD-4 LP with almost perfect separation because dbx-II doesn't need any level calibration like ANRS or Dolby systems do for correct decoding and the sum+subcarrier would de-matrix basically perfectly.
Sounds like a plan to me being whoever would be paying 24.99 for one 45 RPM CD-4 (or UD-4) DMM LP would know in advance what they were buying and would have the proper playback gear, so we wouldn't be having to worry about backward compatibility for regular consumers like they did when CD-4 was out.
BTW, the dbx used in Zenith's BTSC system was a level-dependent system...and early BTSC decoders had...incorrect dematrixing of the sum+difference channels.
So OK Quadfather's old Optimod or whatever wouldn't work, but it sounds like what combinations WOULD work together also wouldn't be THAT big of a deal to marry up dbx II with the improved UD-4, since again we wouldn't have to worry about backward compatibility.
As a side-note, JVC tried to get around paying Dolby patent royalties for ANRS with their Super ANRS system, but it didn't work...
Yeah I remember having a JVC 2-sided quadraphonic CASSETTE player, the two left channels in place of where one would be and the two right channels in place of where one would be to again ensure compatibility with stereo in case some shmo bought one by accident. $11.49 instead of $4.49 I dunno how ``accidental'' that could be but hey it was the `70's a lot of things was messed up then including most of us.
 
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