CD-4 Ramblings and Tech Discussion

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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. 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.

I have the AES paper on the RCA Quadulator and it had phone jack in/out's for every section so limiters, Neutrex II baseband (which RCA didn't use in the Quadulator - probably for cost reasons although they said they couldn't hear its benefit), extra or different noise reduction, EQ changes for mastering speed changes, etc. could all be patched in, bypassing any part of the Quadulator desired, so the dbx-II system could be added in place of ANRS for the subcarrier difference signal noise reduction system. dbx-II allows about 10-db more hf headroom too, so the 30kHz carrier could be cut at better levels - and with the 10-db of headroom dbx-II would add to the baseband sum carriers, the whole shebang would 'fit' better on the LP, with greatly reduced distortion. JVC's ANRS added about 10db of noise reduction - dbx-II on an LP add's anywhere from 20 to 40db of NR, depending on the quality of the vinyl, so I would think some amazing dbx CD-4 (CDBX-4?) LP's could be made. Now if someone could just get a hold of the last working RCA Quadulator.

Lou Dorren's new Demodulator would need to have in's and out's that would allow the user to add two dbx-II NR units, bypassing the built-in ANRS. (you'd need 2 stereo dbx-II NR units - one for the carriers and one for the baseband. dbx-II encoded albums are absolutely the best sound I've ever heard - my dbx encoded copy of "Heart - Dreamboat Annie" is superior to any re-issue of it, including the gold DCC CD. I think because the master tapes were brand new then when the dbx LP was cut. And they used that super quiet vinyl - I've transfered the Heart dbx to CD WITHOUT decoding so when decoded, the dbx will reduce any of the PCM conversions artifacts. (dbx-II with 14- or 16-bit PCM is a great combo and used to be used a lot by recordists) When I play the dbx CD and decode it, it sounds exactly like the LP. I now have to transfer my Diana Ross dbx LP and the many others I have to CD. I have several dbx II decoders, one is a 224 and the other a 128 that also has dynamic range expansion/compression - I use it in the bedroom to compress DVD's - no, not compress - totally limit them, so I can listen at night and not bother my partner.

Can you tell I'm a fan of dbx noise reduction? It was also used by MCA for Sensurround Mod II and Mod III when MCA was trying to compete with Dolby for the high-fidelity theater sound market. Fox briefly considered releasing ALIEN in Sensurround Mod III for it's unsurpassed high-fidelity aspects. And dbx, along with Kintek (and the inventor of HDCD), tried to get their 4-channel discrete Colortek 35mm stereo system into the theater market, but that didn't go anywhere due to its complexity in reading 4 tiny optical tracks and massive 2.8:1 noise reduction compression ratio.

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.

Philips wouldn't allow quad Compact Cassettes on the market and cracked down hard on companies that tried it - like JVC. The Super ANRS (Automatic Noise Reduction System) came later, around 1978 or so, to give a more dbx-like noise reduction instead of Dolby B's (and the original ANRS) piddly 10db. Anyway, Philips would only allow Matrix encoded Compact Cassettes, which didn't work too well considering the tape/head azimuth was so totally off on the vast majority of decks. Later, in the mid-to late 70's, any company could have made discrete Compact Cassettes because the original Philips patents had expired by then - but quad was dead. Teac took advantage with their Portatrack, portable 4-track semi-pro recorders/mixers that ran the Compact Cassette tape twice as fast and used dbx for better sound. Philips was powerless against that. And some high-end companies came out with CC decks that ran the tape at double speed with dbx for better sound - I think Mobile Fidelity even issued some tapes in the double-speed format. MoFi also issued VHS and Beta digital tapes made to be played with Sony's PCM-F1 digital recorder that used video recorders - I remember seeing Dark Side Of The Moon as a VHS PCM tape from them - I was told by Brad Miller that they were all ran off, one at a time, as orders came in - so in effect, each was really a master tape since the data was an exact duplicate of the original U-Matric PCM-F1 master.

I've babbled enough for now I guess.
 
Please, keep on keepin' on!

I do apologize - I tend to write too much and 'wander' onto subjects that are only vaguely related to the subject at hand - I don't mean to derail threads like that, it just kinda happens - and I don't start a new thread because it doesn't seem like enough info to do so. I have actually been chastized by my partner and others online that I babble too much about subjects that interest me - that everyone reading my posts isn't interested in all the little 'technical' things or my opinions on whatever I'm talking about - on another, totally unrelated, forum, I was told to dumb-it-down and write only about 10% of what I normally would because people didn't want to read a book on the subject and it always seemed that I was writing some chapter due to the length of my posts.

So, now, when I write and go off-subject, like about the dbx LP's and stuff, I feel bad - but I can't bring myself to delete it because I've spent all that time writing it, you know? And I have no idea how many people actually like what I write about - not many respond, so I always take that as non-interest. I like to talk and argue and learn new stuff that others know and I don't. And I like to pass on what I know to others. So I'm always torn.

It sucks.

I've been playing with two SMART Devices CS-3X Junior Circle Surround decoders today - connecting them to the Tate decoded front and back outputs of my Fosgate Tate II 101A SQ decoder to derive 'hard' Center Front and Center Back channels/speaker feeds - although there are not many SQ recordings with Center Back on them - Funny Girl and the SQ Test LP are the only two that I know of for sure. For deriving Center Front, the results have been stunning - having a real "center" really improves the imaging of all instruments and allows you to hear more 'into' the mix. Unlike Pro-Logic or Pro-Logic II decoding, the Circle Surround is mainly a gain rider - it keeps Center Front about 10db down in level until a Center Source appears in them mix, then it brings it up to the same level as L/R front and applies a very mild signal cancellation to L/R so you don't end up with all 3 front speakers reproducing the same center image (which can cause audible problems due to comb filtering and such). So far, from what I've listened to today, it sounds better than using DTS Neo:6 or Neural Surround to derive center (they both are better than Dolby's methods because they segment the signals into multiple bands and steer them separately). I haven't listened to a lot though - one thing surprised me - some of the PC decoded SQ DVD's and CD's I've gotten from Torrent have a really messed up center front signal - it's phase is so screwed up that it can't be decoded to come from a summed CF speaker - and all encode/decode formats (except BMX/UMX) use equal level in-phase L and R front to encode Center Front. So I don't know if there's better PC SQ decoded sources out there that correctly decode signals in-between the speakers. My downloads might be old from non-perfected SQ PC decoding, I don't know.

On the Fosgate Tate II 101A's modes besides SQ - the Cinema and Surround positions, the Center Front decoders superbly, but you can't decode a Center Back because the Fosgate decodes the two rear channels out of phase - in the Cinema mode it was done to increase the sense of depth from front-to-back (Jim Fosgate told me that) and in the Surround Mode, the way the signal is re-arranged to make it a 270 wrap-around signal precludes a Center Back because the two rears are out of phase again. And if you flip the phase of one of the rear channels to try and 'fix' it, you've just destroyed the side imaging because now the rear channel you 'flipped' is out of phase with its front partner. The "Surround" 270 mode for SQ Synthesis is basically re-arranging the stereo signal as if it had been encoded with the SQ Forward Oriented encoder, so no Center Back is possible.

I just love how cheap the SMART CS-3X Junior decoders are (70 bucks direct from Smart devices on ebay now - and I think cheaper if you contact Smart and ask about "B" Stock, although the stuff on eBay might be their B-Stock - my two CS-3X Jr's are B-Stock and perform superbly) - If I had the funds I'd buy two more to decode 'Center Side" channels that are encoded on many SQ albums - the Fosgate Tate decodes them correctly (unlike the Audionics Composer or old Full-Logic "Gain Riding" decoders - they 'ignored' the sides and only decoded the 3 front positions and 3 back positions of SQ) Thanks to additional work by Martin Willcocks and Jim Fosgate, the Automatic Dimension Control allowed them to decode the side images (if they were encoded on a SQ release in the first place) and have them be at the proper level and proper phase - actually, they are about 10-20 degrees out of phase between the front/back sides, but that's close enough for a decoder looking for equal level, in-phase info to identify as "center" and decode it correctly. So I'm gonna need two more Circle Surround decoders and two more speakers - and then there is always the 'height' info - but I don't think the "Center Top" position in SQ or the SQ Position Encoder was really meant as an "overhead' channel - it was just a 'in the center of the room" position, like the Carpenters loved to use on Karen's voice in their SQ releases. Although, with the new discrete formats, a height channel has been tried (Dolby Sonic Whole Overhead Sound) and is encoded on the DVD - could Dolby have chosen a dumber name than "Sonic Whole Overhead Sound"????

I'm rambling again... Please, tell me if it's an irritant and I'll refrain from posting about anything other than the direct subject being discussed. Short, direct to the point and nothing more. I want to be a good "Quad Neighbor" on the QQ Forums, you know?
 
Please keep rambling, Disclord, your thoughts are always so informative. I don't think anyone ever complained about learning too much, at least they shouldn't.
 
Now if someone could just get a hold of the last working RCA Quadulator.
Greg Bogantz has most of it. So I was right, then. dbx WAS originally intended for CD-4 so there's no reason it couldn't be used for the new version which I have dubbed DM-4 for Discrete to Metal-4 (channel).
Lou Dorren's new Demodulator would need to have in's and out's that would allow the user to add two dbx-II NR units, bypassing the built-in ANRS. (you'd need 2 stereo dbx-II NR units - one for the carriers and one for the baseband.
Too bad it's already in production. Oh well. There's always a Mark II.
...best sound...superior ...including the gold DCC CD...super quiet vinyl...dbx will reduce any of the PCM artifacts. (dbx-II with 14- or 16-bit PCM is a great combo and used to be used a lot by recordists)..
I do the same thing and have for a long time. Which is how I heard about it: direct to F-1 PCM recording but through a dbx encoder first at Grateful Dead and etc shows my uncles used to go to and tape from.
...sounds exactly like the LP. Can you tell I'm a fan of dbx noise reduction? It was also used by MCA for Sensurround Mod II and Mod III when MCA was trying to compete with Dolby for the high-fidelity theater sound market.
I worked as a projectionist in college, we had a lot of that kind of equipment in the sound rack, hell, we had an old QSD 1 we set up in the HALL mode to play the Non-Sync (intermission music) back through the surrounds when it had them.
(As far as quadraphonic cassettes go) Philips wouldn't allow quad Compact Cassettes on the market and cracked down hard on companies that tried it - like JVC. Philips would only allow Matrix encoded Compact Cassettes, which didn't work too well considering the tape/head azimuth was so totally off on the vast majority of decks.
And not everybody wanted or could afford a Nakamichi.
...Teac 4-track semi-pro recorders/mixers...
Even tho they ultimately lost not only the format exclusivity but also the track configuration. Units like a Tascam 424 use the same equidistant track configuration as that used in talking books for the blind, whereas conventional cassettes used two stereo tracks that occupied the same space as an old monaural track, a large guardband in the center, and then repeated on the other side.
...And some high-end companies came out with CC decks that ran the tape at double speed with dbx for better sound .
Yep. Been there, done that. You ruin across all kinds of crazy stuff in the Legacy Media Restoration world.
...I think Mobile Fidelity even issued some tapes in the double-speed format.
No actual releases though, just dealer demos and test ``pressings'' of which I have a couple like the 25-RPM and real-time mastered CD-4 from Japan that never came out either.

I got a Mo-Fi-branded Marantz two-speed stereo cassette deck for FREE including the box, all peripherals and the matching Mo-Fi branded dbx unit no less as yet another leftover of a guy that died or got a divorce and lost all his gear to the wife who knew zilch about it, bears witness that at least for a year or two these were out. Of course half the problem of marketing was:
A) they needed to use chrome tape because the cobalt or ferrous tape wouldn't give you that good of a dbx tracking and chrome tape was expensive then
B) they needed to use 16-micron 60 minute tape vs the 12-micron 90 min thickness,

So since you could get away with a 68 minutes of tape in a cassette with 16-micron tape , then that gave you enough for 17 minutes of an LP side which usually meant that either one song per side had to go, like 2-track stereo reels of the 50's vs their 4-track counterparts in the 60's, or else they'd take a chance and use 12-micron C-90 tape and just load 92 minutes of tape in to give you the necessary 23 minute album sides and just live with the thinner tape.
MoFi also issued VHS and Beta digital tapes made to be played with Sony's PCM-F1 digital recorder that used video recorders..
That were used a lot by remote-recording engineers if all they had to do was record in Stereo. Or by little high-school kids that wanted to spend a whole school year recording programs for Lock-In Prom Weekend on 6-hour VHS tapes. We had an airline production VHS deck leftover from who knows where and was able to use the PCM tracks for one 6-hour program, the VHS Hi-Fi tracks for a second program and the linear-audio tracks for either a third stereo program or a third and fourth mono program just like the airlines did.

For those though, we recorded in advance onto one-hour 2-track reel-to-reels, and then just lined up three (or four) reel to reels for the final encoding pass onto the VHS, one reel deck going through the PCM, one deck going to the VHS Hi Fi and one or two decks going to the linear stereo low-fi tracks. Since each of the hour-long reels would be over at the same time, we could pause the VHS while we changed reels on the 3 decks and then resume for the next hour alllll niiiight lonnnnggggg for a week before prom.
I remember seeing Dark Side Of The Moon as a VHS PCM tape from them - I was told by Brad Miller that they were all ran off, one at a time, as orders came in - so in effect, each was really a master tape since the data was an exact duplicate of the original U-Matric PCM-F1 master.
As all VHS tapes must be as there wasn't (and still isn't) a way to duplicate videotape at high speed. Which is why the first VHS movies were 89.99 a pop or more.
But, back to talking about cassettes.
That, and the Tascam tapes were recorded at 3-3/4 instead of the normal 1-7/8 or the talking book's 15/16, at least that was all derivative of the same 30-IPS mastering speed. For the department store uses of the same technology, true they used the equidistant track format, but they used a derivative of 22-1/2 IPS instead of 30, so the department store reel to reels ran at 5-5/8 instead of 7-1/2, their cartridges all ran at 2-13/16 instead of 3-3/4 and their cassettes ran at 1-29/32.

And then they all ran backwards besides, meaning if you tried to play them on a normal stereo player, the tracks that would have ordinarily been where Side 1 was located was still there, it was just recorded right to left like a microcassette instead of left to right. For a VERY short period of time backwards carts were also produced that looked just like a mirror image of a normal 4 track (or broadcast) cart with the hole for the roller on the left instead of the right and wound from the right to the left instead of left to right.

So if you wondered why you could never play the department store tapes on anything but a 4-track 4-channel quadraphonic tape player (with the exception of the reverse cart versions you had to unwind onto a reel beforehand and then play them ``backwards'' on the reel to reel), now you know.
So I don't know if there's better PC SQ decoded sources out there that correctly decode signals in-between the speakers. My downloads might be old from non-perfected SQ PC decoding, I don't know..
Best way to find that out is to see if you can get the raw undecoded SQ-encoded file somewhere and then go onto this board's SQ Decoding in Adobe Audition 3.0 thread and after finding a copy of Adobe Audition 3.0, try it how they tell you to on there and see what happens. Or go back to your Tate II and compare with the AA 3.0.
No Center Back (SQ decoding) is possible.
Not without either a real or digitally reconstructed Ben Bauer London Box anyway. That's why so many tests involved trying to overlay SQ on EV (mirror images of each other) with the rear phase variances from Dynaquad laid over that and then the London Box signal laid over all THAT. Which is exactly how they tried to make 12-channel or 14-channel matrix in the late 60's and never could come up with a way because of how terrible the steering circuitry was at the time.
So I'm gonna need two more Circle Surround decoders and two more speakers...
Or, being an engineer yourself, just re-design something from scratch that can retrieve SQ laid over EV with the rears from Dynaquad laid over all that and a London Box signal laid over all THAT all at the same time. And then throw in a QS Regular Matrix and Vario Matrix just to make people happy.
I'm rambling again...
/me singing The New Christy Minstrels under the following for ambiance...http://www.youtube.com/watch?v=3kgaD8LFSfg middle track).
I do apologize - I tend to write too much and 'wander' onto subjects that are only vaguely related to the subject at hand - I don't mean to derail threads like that, it just kinda happens - and I don't start a new thread because it doesn't seem like enough info to do so.
Welcome to Engineering.
It always seemed that I was writing some chapter due to the length of my posts.
Or a book like I've been accused of repeatedly. My response? People need to understand engineers.

Grammy award winning record mastering engineer Bernie Grundman once said to a young inspiring engineer: ``Engineers are either 0.53% or 0.56% of the population depending on which story you believe. If you believe the theory that 1 out of every 187 people have the intelligence, ability, and expertise of an engineer, then that's 0.53%, and for each one of those three that you have intact, take the square root of that 0.53%.

So if you have the intelligence and the ability, it's 0.2809% and if you have all three, you are 0.7890481% of the population. Which incidentally according to one Hollywood legend was Mr Grundman's phone number at one time (long since disconnected) and if you believe the other theory, that you are 0.56% of the population, that leaves 99.44 percent of the population who will have zero understanding of ideas you're trying to convey.

WHICH EITHER MEANS that the world is 99.44 percent pure and it's the world's impurities (engineers) that give the world it's flavors and textures and/or that being one or more of the above is still nothing to commit homicide or suicide over. (187 is police code for that), then either way it's nothing to get all worked up over.
So, now,...I can't bring myself to delete it because I've spent all that time writing it, you know? I like to talk and argue and learn new stuff that others know and I don't. And I like to pass on what I know to others. So I'm always torn.
Welcome to Being a Guy 101. See above under 0.56% or 0.53% courtesy of Bernie Grundman. And I'm the same. If ONE PERSON wants to know I'll tell them, if not, then it's an excuse to write more blogs in my spare time, from which I can then edit to come up with a book.
Please, tell me if it's an irritant and I'll refrain from posting about anything other than the direct subject being discussed. Short, direct to the point and nothing more. I want to be a good "Quad Neighbor" on the QQ Forums, you know?
Nope, good to have a sparring partner in a fellow engineer.

(LOL) We sound like a buncha guys yakking it up at four in the morning during setups for the electronics and record swapmeets held periodically in the parking lots at the jr. colleges that's been going on since the Dawn of Man. Nobody else but them and their disciples ever cares about what they're yakking about either.

Me, anytime I got bored I'd just make the rounds of electronics, records, tapes and broadcasting and recording guys, most of whom in those days were mutually intolerant of each other.

Your turn Disclord. (LOL)

Now back to your regularly scheduled program about CD-4 Demodulator.

I still wish Lou would consider adding the original dbx-II back into the design as an option besides the ANRS plus all the extra ports mentioned above on the original Quadulator in case we get a new version and patrons to fund the development research.

I am sure when Lou has more information about it, he will be therecoming forthwith..
..forthcoming therewith? withworth corthfoming? It's late I need food and sleep.
 
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I do apologize - I tend to write too much and 'wander' onto subjects that are only vaguely related to the subject at hand - I don't mean to derail threads like that, it just kinda happens - and I don't start a new thread because it doesn't seem like enough info to do so. I have actually been chastized by my partner and others online that I babble too much about subjects that interest me - that everyone reading my posts isn't interested in all the little 'technical' things or my opinions on whatever I'm talking about - on another, totally unrelated, forum, I was told to dumb-it-down and write only about 10% of what I normally would because people didn't want to read a book on the subject and it always seemed that I was writing some chapter due to the length of my posts.

Don't worry about it, We're smart enough to skip it if we don't want to read it.
Quadfather
 
It seems it would not be difficult to install patch in points for a second NR system. And then have a companion unit for the chosen format.
The Quadfather

P.S. Of course, what you are doing is adding yet another quad recording format. It seems that quad will always be fractured into many formats.
By the way, wasn't Neutrex designed to make cheap record players sound good? Why would we need it?
 
when it comes to using dbx you wouldn't get Steely Dan's vote
http://www.steelydan.com/dennys3.html note paragraph 5 onwards...

The primary reason that there is Engineers and there is Musicians.
And the primary reason that modern music and engineering programs make both kinds
of students take at least the first year if not the first two of the opposite program
compared to in those days when there was Musicians and there was Engineers.
 
The primary reason that there is Engineers and there is Musicians.
And the primary reason that modern music and engineering programs make both kinds
of students take at least the first year if not the first two of the opposite program
compared to in those days when there was Musicians and there was Engineers.

but the Roger that went to dbx headquaters with the dbx endoded 24 track steely dan tapes, that dbx couldn't fix was a recording engineer


http://en.wikipedia.org/wiki/Roger_Nichols_(recording_engineer)

and paragraph 6 of the steely dan link

Several of us formed a contingent to storm dbx headquarters. We packed up the tapes and the dbx units and Gary and Roger (and one or two others) boarded a plane to the East Coast. They confronted dbx and discovered that no one could fix it or explain it. The people at dbx built us a special pair of units with adjusting knobs that could alter the settings that are normally sealed inside at the factory. This too was a miserable failure.
 
By the way, wasn't Neutrex designed to make cheap record players sound good? Why would we need it?

Neutrex-I and Neutrex-II originally came out of a 1960's RCA research project that had as its goal 'better' LP sound for all listeners, but especially on the low-cost phonograph 'console' units that RCA liked to sell (RCA could never ignore cheap now, could they?) - European, UK and Japanese LP's were being imported and sold in droves due to their high sound quality and RCA, (instead of just using better vinyl and mastering quality with more care in pressing the LP in clean-room conditions) chose to try a technical end-run around the problem. The RCA R&D project was code-named "Dynagroove", as the final LP system came to be called, and one part, the Neutrex groove pre-distortion, later got the name Dynagroove when RCA dropped the other aspects of "Dynagroove" - finally, to distance it from the negative connotations the name Dynagroove had in the US market, JVC renamed it Neutrex. In addition to the truly beneficial groove pre-distortion, the 'original' RCA Dynagroove process also used a variable inverse of the Fletcher-Munsen 'equal-loudness' contour, that modified, during the LP mastering, both the level and the frequency response of the various sounds from the master tape (totally destroying what the artist/engineer might have been trying to achieve!), it also had a multi-band limiter so the compressed Dynagroove LP's could be played at parties and such and all those "pesky" low-level sounds could still be heard! Later, Dynaflex paper-thin vinyl was added to the whole shebang, but other than the groove pre-distortion, the rest of the 'parts' of Dynagroove had been dropped by then - the system really made LP's sound worse, especially on low-cost consoles. The only thing that truly was a breakthrough for LP mastering and playback, and made LP's sound better, was the pre-distortion (RCA named it "Dynagroove" when RCA dumped all the other 'features' of their original Dynagroove system. And JVC refers to the pre-distortion system as Dynagroove in some of their very early CD-4 tech documents.

So, anyway, no, Neutrex, was used on both CD-4 and regular LP's (mono, stereo, matrix quad) to increase fidelity and dramatically reduce playback distortion that was caused by the stylus not being able to follow/track the very narrow and rapid high-frequency bends of the LP groove on recordings with lots of high frequencies (it improved the lower spectrum too). It worked by pre-distorting the groove on the master so that when the LP was later played back, the stylus actually tracked it with more accuracy and less distortion - it was kind of a 'negative feedback' process for physical grooves. (Although LaserDisc's were optical and not mechanical like an LP, Pioneer had to take a Neutrex-II patent license because they used a 'similar' method of reducing interference between the right channel analog FM audio carrier and the video's chroma signal when playing an LD. When it was combined with CX Noise Reduction, a 'better' LaserDisc was the result. Later, it was also used to prevent the CD Red Book audio data on an LD from interfering with the picture signal, where the 16-bit PCM audio data could show up as a noisy pattern in dark parts of the picture)

Back to CD-4 and Neutrex... There's some great diagrams and explanations of how it works on Old Quad Guys Quad info site - I extracted just the Neutrex info from 2 of the JVC docs and made a 2 page PDF - here's the link to view it: http://issuu.com/disclord/docs/jvc_cd-4_neutrex_description?mode=a_p

Used either for CD-4 Quadradisc mastering or stereo/mono/matrix quad LP mastering, Neutrex worked very well - It basically came into standard use by all record companies on all LP's by the mid-70's or so, and it never really fell out of use that I know of. (there were no drawbacks to its use, so no reason not to use it) Neutrex-II was a separate process, but basically the same system, for processing the 30kHz HF difference subcarrier signals and their sidebands on CD-4 LP's, allowing dramatically reduced distortion of the recovered 30kHz carrier - and again, better final sound quality when the Sum & Difference signals were de-matrixed. (I often get Neutrex I and Neutrex II mixed up in my head - which one was for baseband and which was for the subcarrier - but it doesn't matter really - the basband 'main' sum signals used the RCA Dynagroove Neutrex-I system, while JVC modified it for the CD-4 difference subcarriers and called it Neutrex-II)

The best way to think of Neutrex on any CD-4 or stereo/mono/matrix quad LP is that it's like Dolby HX-Pro for cassette decks; Dolby HX-Pro works during recording only and doesn't require any form of decoding, so every cassette recorded with HX-Pro gave higher quality playback, even if the deck had no noise reduction at all. With dbx Type-II, Dolby-C or Dolby S noise reduction, the results could be jaw-droppingly amazing.

It's interesting to note (interesting to me anyway) that just as Neutrex was an RCA invention that was later improved by JVC, Dolby HX-Pro was a Dolby Labs invention that was later improved by Bang & Olufsen. Dolby's original HX System (Headroom eXtension), for Compact Cassettes and low-speed open-reel, didn't work too well and Dolby was was failing in getting companies to use it for prerecorded cassettes or making decks that could record using it, but Bang & Olufsen had something kinda similar and when the two were combined, the system, now named HX-Pro, worked perfectly. The benefits of HX-Pro were so audible that tape duplicators took up the system and deck manufacturers started incorporating it their better decks almost overnight. As far as I know that was Dolby's first partnership on a technology.
 
but the Roger that went to dbx headquaters with the dbx endoded 24 track steely dan tapes, that dbx couldn't fix was a recording engineer


http://en.wikipedia.org/wiki/Roger_Nichols_(recording_engineer)

and paragraph 6 of the steely dan link

Several of us formed a contingent to storm dbx headquarters. We packed up the tapes and the dbx units and Gary and Roger (and one or two others) boarded a plane to the East Coast. They confronted dbx and discovered that no one could fix it or explain it. The people at dbx built us a special pair of units with adjusting knobs that could alter the settings that are normally sealed inside at the factory. This too was a miserable failure.

From reading the link provided, it sounds like the results you get with dbx if you mix down encoded tracks without decoding them first. I doubt that's what happened, but it has happened in the past (just like there were many LD's and Hi-Fi tapes that had Dolby decoded on one channel but not the other!). When dbx encoded tracks are mixed down without first decoding them, they simply won't decode correctly at all.

MCA Systems used that to good effect with Sensurround Mod II: When making the Sensurround master mix, they encoded the main program with dbx Type II, then mixed the rumble (without dbx encoding) and the 25Hz/35Hz Front-Back Sensurround Control Tones together and mixed them (again, without dbx encoding) with the dbx encoded program soundtrack. When played in the theater with the Sensurround Control Box that had dbx II decoding built in, the main soundtrack got expanded back to its correct dynamics while the rumble was expanded 2x in volume, allowing the optical track to give 80db dynamic range plus rumble effects at 110-120db and not requiring outboard rumble generators in every Sensurround control box like "Earthquake" did. The Control Tones allowed the Sensurround effects and program audio to be panned front to back or to have the rumble running along with dialog and not have it (dialog) coming from the back of the theater. MCA removed the traditional Academy Roll-Off from the optical recorders and in theaters, so the final spec's of Mod II and Mod III Sensurround were a frequency response of 16-Hz to 16kHz, 80db dynamic range & S/N, plus surround sound type effects, all from a mono optical 35mm print. MCA was really pushing marketing of the Sensurround Special Effects System, as it was then called (and later to be called Sensurround Plus) as a competitor to Dolby's Dolby System (Dolby wasn't always stereo or surround back then). But to most people at the studios and theater owners, Sensurround simply meant huge amounts of rumble from gigantic horns that required seats to be removed from the back of the theater to fit them in, and did not associate it with very high quality 35mm optical soundtracks that had extended frequency response and surround sound effects. Sensurround Plus, used for the film Zoot Suit, used dbx II NR on the 4-track mag prints for 90db dynamic range and the 25/35Hz control tones to increase the sound levels during the musical numbers and, in a few theaters, synchronize special light arrays to the films effects (Sensurround Plus with Lightsurround it was called - the Cinerama Dome used both for Zoot Suit). dts did the same in-theater light effects many years later for the Jurassic Park II trailer. It's just too bad that they didn't do it for the film run - the dts light effects trailer for JP II left many people thinking the film would be released in that format.

Sensurround did get one last tryout under the name "CineSonic Sound" for the film Airport 1979: The Concorde. The one-sheet's and trailers have a logo that read: Special Effects In The ALL NEW CINESONIC SOUND.

Airport 79 was a major financial failure and so MCA sold off the Sensurround patent rights and their Sensurround name rights to dbx/Kintek in 1982 or so. Cerwin-Vega held co-ownership of the Sensurround name only, which they utilized for a few years in the early 90's, selling a turnkey home theater speaker system - in competition with Shure HTS and THX (Shure did it first though - THX simply copied it!) The overall sound of the system was excellent, but the sub's Cerwin-Vega used were SERIOUSLY under-spec'd - none went lower than 25Hz! That's not Sensurround territory! They should have gone with a W-Horn or a corner horn with a mouth extender to get 16-Hz @ 110-db or so in the home - THAT would have been successful in the market, I think.
 
but the Roger that went to dbx headquaters with the dbx endoded 24 track steely dan tapes, that dbx couldn't fix was a recording engineer.
In the Royal Crown Colonies (England, Australia, Canada, etc, etc,) we refer to these individuals as Sonic Balance Operations Technicians, i.e. equipment operators, not designers, technicians or engineers.

Which is why they went to dbx in the first place, but therein likes all kinds of problems and why nowadays they have engineer-musicians and musical technologists and musician-electronics-design people and..... .

... When RCA dropped the other aspects of "Dynagroove" - finally, to distance it from the negative connotations the name had in the US market, JVC renamed it Neutrex.
Negative connotations which were well-edeserved at the time.
...(totally destroying what the artist/engineer might have been trying to achieve!)
Yep. Commercialism at its' best. Nevermind artistic integrity. But then when has ANY label cared what the artist wanted?
Later, Dynaflex paper-thin vinyl was added to the whole shebang....the system really made LP's sound worse, especially on low-cost consoles.
Which in its' original incarnation was supposed to make it sound better on exactly those types of players. I always thought``Dynagroove'' in ANY form was dead once Dynaflex came around.
So, anyway, no, Neutrex.. worked by pre-distorting the groove on the master so that when the LP was later played back, the stylus actually tracked it with more accuracy and less distortion - it was kind of a 'negative feedback' process for physical grooves.
Except one problem: adding PRE distortion on top of the NORMAL distortion even if it's trying to be an exact inverse is not always an exact science.
Pioneer had to take a Neutrex-II patent license because they used a 'similar' method of reducing interference between the right channel analog FM audio carrier and the video's chroma signal and CD Red Book...
so you're talking PAL LD's then since NTSC LD's PCM standard was NOT Red Book, being it was 44.056KHz instead of 44.1 which is why you need a dual-format player to play the PCM tracks on both NTSC and PAL LD's being only the PAL is Red Book standard. And four percent sharp besides because of the 25 FPS speed up from 24.
...PCM audio data could show up as a noisy pattern in dark parts of the picture[/I])
Which is why it worked better on optical media as an RF band-isolator rather than as an electro-acoustic playback assistant.
Back to CD-4 and Neutrex...basically came into standard use by all record companies on all LP's by the mid-70's or so, and it never really fell out of use that I know of. (there were no drawbacks to its use, so no reason not to use it)
Except the sonic drawbacks of interfering with the artist's wishes.
With dbx Type-II, Dolby-C or Dolby S noise reduction, the results could be jaw-droppingly amazing.
Which is why it would be nice if whatever we end up with now could use the dbx instead.
When dbx encoded tracks are mixed down without first decoding them, they simply won't decode correctly at all.
Because the effects of encoding differ with each different program material unlike Dolby A which just have frequency-enhancers at certain bands. I can't tell you how many balance engineers I know have either mixed down from a 16-or 24-track Dolby A master without decoding just so they wouldn't have to decode and then re-encode on the final 2-track mixdown.
The Control Tones in Earthquake allowed the Sensurround effects and program audio to be panned front to back or to have the rumble running along with dialog and not have it (dialog) coming from the back of the theater. Sensurround did get one last tryout under the name "CineSonic Sound" for the film Airport 1979: The Concorde.
Interesting re-use of a 40-year old technology from Fantasia.
To have gone with a W-Horn or a corner horn with a mouth extender instead of the sub's Cerwin-Vega used to get 16-Hz @ 110-db or so in the home would have been successful in the market, I think.
If they could have ever gotten the prices therefor down out of the stratosphere that is.
 
Hmmm interesting, this Neutrex. It sounds like how we pre distort television signals before we feed them into a Klystron, or IOT inh a television transmitter. The process is intended to overcome non linearities in the klystron so that the transmitted signal doesn't have them. (For those who don't know, a klystron is a vacuum tube that is designed to operate as an amplifier at UHF frequencies and power levels of approximately 30 kilowatts output)
 
It sounds like how we pre-distort television signals before we feed them into a Klystron, or IOT in a television transmitter.
Except all Klystrons are pretty much the same and have pretty much the same non-linearities. But all the ubiquitous Astatic or Tetrad or Electro-Voice or any other ubiquitous inexpensive ceramic cartridges mounted upon the equally-ubiquitous all-plastic Garrard or BSR record changers upon which the vast majority of Dynagroove pressings were played, do not have even CLOSE to the same distortions. So, again TV, like LaserDisc is a different animal entirely.
 
Negative connotations which were well-edeserved at the time.

No doubt - the whole Dynagroove project, except for the carrier pre-distortion, was one of the worst things RCA ever did to the LP format.

I always thought``Dynagroove'' in ANY form was dead once Dynaflex came around.Except one problem: adding PRE distortion on top of the NORMAL distortion even if it's trying to be an exact inverse is not always an exact science.

Nope, it just got the name changed to Neutrex or "groove pre-distortion", etc... The pre-distortion used by Neutrex is an approximation, of course, but the playback tracking is much more accurate and the high frequency tracking distortion is an order of magnitude lower using the Neutrex (let's not call it Dynagroove) than on an LP cut without it. In the PDF I linked to, you can see how the stylus tracks the pre-distorted groove more accurately and why it became a standard part of LP mastering.

I'll have to come back to answer the rest of your reply (the LD bits and multi-track mixdown) a bit later, when I've had more coffee - well, tried to gag more coffee down anyway. I'm losing my ability to swallow and so I get the fun of having an endoscopy and and other "oh, joy-type" tests in another week or so. Thus, I'm currently not getting my normal US-RDA of coffee as early and as easily as normal - and it keeps me fuzzy mentally until I've gagged enough down. It helps to supplement with a caffeine pill.
 
Neutrex...(let's not call it Dynagroove)...tracking distortion is an order of magnitude lower than on an LP cut without it.
OK so Dynagroove went on a diet like most of the engineers that put it together need to do (rolleyes - LOL). Losing 50% of its' bodyweight (an order of magnitude lower) it could have won any season of The Biggest Loser it wanted to if they would have had it in those days. Just goes to show you when technology gets too fat it has the same effect on its' environment as when its' engineers get too fat (LOL).
 
Yes. We want to cut new CD-4 DMM and press them on the 180G grainless red or blue audiophile vinyl

Nice!! Very nice!! But two suggestions:
(1) Use black vinyl, it is almost always quieter than colored vinyl.
(2) Forget about record weight, it is the quality of the record compound that matters. Philips 1980s records being a prime example of thin records that sound fantastically good.
(3) If you could get something similar to Q-540 record compound, it would be great. In any case, you need a vinyl compound that can withstand more pressure. That is, its resistance to plastic deformation should be higher.
 
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