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

I have no problem with 5.1, but it is true that the extra center channel is unnecesary for music. It's purpose is to localize the dialogue to the screen when one is to the side of it. If you are in a theater next to the wall on the front row, all you hear is the speaker next to you when the phantom image is used. With a real channel, the sound is more localized. 5.1 is designed for theaters, and what we have in our homes is a holdover of that. We owe DTS a debt of gratitude for renewing interest in surround sound for music. And also Dolby for keeping multichannel alive in some form during the dry years until it could be ressurected. Unfortunately the dry years have returned. I have no doubt that there will be viable surround formats capable of reproducing music (in a lossless way) but will music be recorded on them in a format other than band in front audience in back? Who knows. It all depends on whether producers will be willing to produce music in surround that won't generate staggering profits. I wish they would produce the stereo discs and make their money and then turn the master tapes over to some small operation who just wants to make a decent living for their employees. Is the demand so small that that cannot be done in a profitable way? Or are the studios so uptight about their royalties that they could not work out a per unit sale price? Who knows.

The Quadfather

Hello Quad folks,

justforthesoundofit,
In Speaker Placement, Symmetry is the word. Quadraphonic sound is two dimensional by nature. It has an X vector (Left to Right) and a Y vector (Front to Back). To accommodate this the speakers should be in the four corners. Normal Speakers (Not Bose) have a wide cardioid dispersion pattern, so the Left Front should be pointing to the Right Back and visa versa. The Left Back should be facing the Right Front and visa versa. The 5.1 speaker placement of the "surround speakers" demonstrates the the non symmetry of this system. This set up assumes that there is very little point source information in the surround speakers. This started from the matrix 2 channel version of 5.1 which has very little separation Front to Back. In most 5.1 mixes, Ambience is what is found in the surrounds.

If true Quadraphonic reproduction is the goal, then 4 Full range loudspeakers, one at each corner facing Criss Cross is the ticket! Square rooms are ideal but rectangle ones work well.

Lou Dorren

The Quadfather has is right. 5.1 was designed for theaters. The center channel is necessary for the large auditoriums of first run and large “classic” theaters. When you have to sit near the right wall, you are to the right of the right speaker, and without the center speaker all phantom center images would appear to come out of the right speaker.

And quadtrade, Thom Holman did not start “us off on this center channel and point one crap.” Bell Labs, ERPI, Westrex, Fantasound, all the early studies in multichannel sound reproduction in large rooms found the center channel was necessary. Thom only documented it, and put it in his standards.

The .1 channel? He did not create it, he just gave it the nomenclature of .1. The proper name is the LFE, or low frequency effects channel. In motion pictures, it does not necessarily have any common information shared with the main channels.

Think of the movie Earthquake for example. The LFE channels sole purpose was as an effect, to shake the theater and it's patrons. This was well before Professor Holman or Lucasfilm was involved in theater sound.

For many years I have been the secretary of an SMPTE A12 committee that Thom Holman sits on. Another member says Thom reminds him of Don and Carolyn Davis. They are given credit for a lot of original ideas, but when you study these ideas you find out that they have just collected them from a thorough review of the past. Nothing really new.

I give Holman more credit than that.

Now when it comes to your home listening room – that is a completely different acoustic. Large auditorium acoustics do not necessarily translate to small spaces, nor visa versa. I attended a lecture by Dr. Leo Beranek a couple of months ago, and he beat that fact into our heads.

Base Management? I disagree with it for many systems, but it is necessary to check your mix using a base management system in todays world because so many people use them in their home systems.

To sum it up, do not assume that a sound system designed to augment a motion picture in a large auditorium with lots of people is the best sound system to use for listening to music in an intimate small room.

(What does this have to do with the topic 'A new CD-4 Demodulator!!!' ?)

Lou,
there's a little thing on which i disagree about the speaker placement: square rooms are NOT ideal for ANY audio. Stationary waves will find a wonderful opportunity there to destroy any correct audio composed by any number of speakers.
A square speaker placement on a rectangular room is a different beast and can sounds ok.
BTW, on the Japanese King and RCA Cover or OBI of their cd4 LP they shows both placement, with the speakers 1) at four corners 2) two in front and two on sides.

Regarding CD-4 and VHS Hi-Fi:

VHS Hi-Fi suffers from audio noise due
to discontinuities in the FM carriers
caused by the rotating audio heads
switching from one head to the other and
videotape dropouts.

Various methods have been devised to
smooth over the audible effects of these
VHS Hi-Fi FM carrier problems.

Are any of these smoothing methods
applicable to CD-4 (to deal with problems
in the FM based difference signal carriers)?

Kirk Bayne

Why we talk about other generally quadraphonic themes beneth the maine or hit theme demodulator? Because we will make a "while away the time" till we can read the chapter 5 from Lou or can finally self work, adjust and listen with the new demodulator.

I think, some of the comments from Bonzodog are right - but for the cinema sound by cinema conditions. At home we have others. And so it is doesn't matter for home surround, what big studios for a cinema-surround mixing prefere. So there are not needed at home unsymmetrical places for the speakers, different working speakers (in front big, in the back little or with a diffuse sound). And who will have real cinema surround at home, he must have more than 5 speakers, because in cinemas that are the numbers already for the sound from the frontal direction from Cinerama at the 50's till today SDDS . But this is a real channel inflation for the surround at home with the same results as inflation on the market: less and less people can or will take part. That is also the problem of SA-CD and DVD-Audio from the sight of the CD stereo listener with his only 2 channels. Why they must need for a "bigger" or surround-sound therefore a technic like cinema-surround? A real quadraphonic listening set with "only" 4 and full frquence speakers with dircetional sounds in symmetric position needs no THX with timbre matching etc.

When looking to the typical illustrations for an 5.1 set and a 4 channel set each can see, that 5.1 is unsymmetrical, but all natural sounds come to us from a symmetric surround field - like Lou says also. No direction is prefered. And nearly no one can place the loudspaekers at home in exactly those angles as recommended by 5.1, because there are other conditions like room dimensions and different pieces and places of furniture. But a place near the corners is most found. So many 5.1 sets are unintentional placed like the quadraphonic mode.

I have had my 4 big speakers placed in a nearly squared room directly in the corners edges with a well sound without the often reported or mentioned ringing in the bass. Now I have a little more rectangular room and the speakers again in the corners (they must not have an placing in exactly 90°) with also a clearr sound. Sometimes there is a difference in theorie and practice. And the indication from winoper to the early additional ore variable placements of the 4 speakers with the 2 rear speakers instead behind now beside the listener will show us only, what childish games sometimes are prefered especially in the japanese (not only) HiFi scene (look to japanese hi-fi papers). Surround means of course always around and not a double stereo-frontal sound.

So far my contribution for your diversion at weekend.

Dietrich

Hello Quad Folks,

Bonzodog, Every venue has preferred and non preferred sound positions. The dialog speaker does not do much to correct non-preferred auditors. Lets take a real world analog, a play or opera. Assuming no sound re-enforcement, auditors in the non-preferred position lose some of the auditory position as the actor moves to the other side of the stage. There is however, auditory cues which become re-enforced with the visual ques. An interesting side light. An audio mixing engineer that works with me, Paul Stebbins, is totally blind from birth. Having never had any visual ques to re-enforce positioning information, he is very accurate in identifying sound location whether in the preferred or non-preferred position.

The dialog channel does not correct the non-preferred position problem and at the same time corrupts the preferred position playback. The reason that the film industry wanted the dialog channel, was that the playback setup in a typical theater was so poor because of lack of setup standards. This coupled with poor mixing techniques by the film sound mixer, would often make the dialog hard to hear in the theater. The dialog channel is a band aid to fix a problem that could be solved by proper mixing techniques and a good theater audio playback standard.

THX was an attempt to do this. Understanding that THX is nothing more than a measurement standard for theater sound performance, it is irreparably tied to 5.1. THX by the way comes from Lucas' film THX1138 made in the 1970's. The film industry has never been very good when it comes to sound, and Dolby, DTS, and SDDS have not helped in this endeavor.

As far as the sub-woofer, my friend Gene Cerwinsky developed this very large, very low frequency, true sub-woofer. The .1 speaker is really a woofer, not a sub-woofer. The term sub-woofer means below woofer frequencies. Gene's transducers for the movie Earthquake could deliver high Sound Pressure Level (SPL) at very low frequencies (3Hz). Thats a sub-woofer!

Every venue has a solution that yields the same auditory results, however, each solution is different and is handled on an individual basis.

winopener, Techniques in the real world to control standing waves in a square venue are well known. It would probably be more definitive to have the speaker layout square inside the venue. That is full symmetry. Rectangle layouts will also work with a bit of space distortion. Front and side speakers do not reproduce a two dimensional sound field and in my opinion are unsatisfactory.

Bass management in my opinion is very simple. Don't!!! Use 4 full range loudspeakers with good low frequency response and you are home free. Let the sound management, bass, midrange, and high frequencies be handled by the artist and mixer.

kfbkfb,
Kirk, Carrier drop out compensation is included in the new design as it was in the QSI5022. Carrier dropouts in CD-4 are very, very rare. When they occur, The carrier dropout compensator stops the sub-channel for the loss time plus a small hysteresis. It is so fast that the burst loss of Front to Back separation is not noticeable.

Lou Dorren

Hello ZZYZX, has you answered to Lou or me - Dietrich ? I think nearly to me. So I have the chance for an answer and further explanations.

Nothing about your John Eargle and especially those engaged experts, who have fight for a theme, from that they was or are further on convinced that it is right - like quadraphonic sound - without some new stylish flows.
But with my quadraphonic experiments and experiences I think, I don't need stylish experts. It seems, some experts in their commitees ar sitting in an ivory tower without any connection to the consumers. And those experts have brought us such successfull things like SA-CD and DVD-Audio or HD and Blu(e)Ray. And that we have now thankfull only one new blu video record is not from the wisdom of experts, but from the laws of the market and also the consumer with their till now reserve. That was a danger for both to have finally a fiasco.

But back to the technic themes. I have not reported, that in the cinema front are different speakers. Of course, they are there from the same sort (in the back and beside there are often others). I wanted only to explain, how extensice the cinema technic is with 5 speakers there, which we don't need for home surround in the front. And an ideal 5.1 setup should need also speakers of the same sort in front and back - like the 4 for Quadraphony. But the reality is often some different. By fans of "modern" surround I have sometimes seen very bad situations. Not only a different speaker for the center, which will reproduce also an different sound, but there are center speakers 2 yards away from the TV.

It may be, that for cinema sound the dialog sounds are not mixed only to one center, but by DVD it is often in this manner. Especially cinema conoisseurs misses the expensive panorama mixdown of films in past times like CinemaScope, Todd AO etc.

Your assumption, that one at home - equal if stereophonic or quadraphonic listener - will take a place direct before a speaker left or right is a nice theoretic game, but no one will do this. But this can be a real situation in the cinema - and therefore we need there a separate center information.
Also from stereo listener I have heard till now not a word about missing a separate center. But speciality freaks we have of course always.

With SA-CD and DVD-Audio we have fortunately some well mixdowns in the quadraphonic mode, which meens full power in each and also rear channels. But often we can really feel, that the sound engineer has had an anxious feeling to make too much by the mixdown. A dread before the producer or the puritans in the HiFi-paper with theire stiffen views. For example: Listen to a DMP big band new surround mixdown and those of Enoch Light. The 70's quadraphonic production will blow the new away. Quadraphonic recordings, and productions have been most really creative, like to make experiments with the new surround possibilities and taken all sound chances for a real new sound around.

That is, why we quadraphonic fans are so interested for the new demodulator. So we hope to have any more brilliance for our CD-4 gems.

Dietrich

So far my newest comment.

Dietich

Quadro-Action said:

Listen to a DMP big band new surround mixdown and those of Enoch Light. The 70's quadraphonic production will blow the new away.

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I remember during the early 1960s hearing my first Command album recorded on 35mm film. Enoch Light and the Light Brigade were amazing. I still have the vinyl in my collection.

I own also a lot of the stereo LP's from the late 50's and early 60's from Enoch Light. He was also in the before-quadraphonic times one, who has enjoyed full the possibilities of more channels than one. His music and sound was in that time a state of art for sound gourmets. Listen those early Stereo records (also others with an expressive stereo-sound) one can realize the different to actual stereo recordings. In the past one can listen real different positions from left to right in the sound front. Today it often seems, that the stereo-sound would be a more monophonic sound-cloud without clear sound position from left and right. May be also a reason for some more
low-key surround-mixes today.

And what about zzyzx? On the flight from my arguments? It doesn't matter. We quadraphonic fans since the 70's knows a lot about surround - also without to be a commercial expert in today circles.

Dietrich

And now back to the Lou Dorren thread already in progress... please.

Can we keep this thread for things about the new demod and othere things can go into off topic.

Thank you

Bob Romano said:

And now back to the Lou Dorren thread already in progress... please.

Can we keep this thread for things about the new demod and othere things can go into off topic.

Thank you

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I'll second that. Let's focus on new CD-4 Demodulators and Lou Dorren here.

We have an "Off Topic" area for other topics....

psssttt... I know, but I cheated. :spot

Hello Lou,

I’m looking forward to the new CD-4 Demodulator. I have a large collection of CD-4 records.

I know you’ve spoken a bit about SQ decoding, and it is most likely the worse form of Quad ever invented. But nevertheless many recordings are SQ or QS only and we still need to deal with them. I am working with both vintage machines and computer script attempting the best possible decoding that’s available now.

My Question is this:

Is 100% decoding of SQ and QS recordings possible? Or is it like trying to take two glued pieces of paper and separating them. Is it possible to measure the db of separation one is getting from machines or computer decoding?

The Tate machines go for big bucks $$$ and as I understand it once their chips are fried, so is the machine forever. Is it theoretically possible to build an SQ / QS decoder with off the shelf materials that could match or exceed what the Tate models can do without it costing an arm and leg?

Thank you for your advice and opinions!

The Quadfather said:

I don't think you have to worry about Bush, he's on his way out. What you need to worry about are the marxists that are coming in. The republicans are in trouble because they promised smaller government and didn't deliver. But the alternative is much worse. There is no one that represents individual freedom in the presidential race. Or are you not for that?

The Quadfather

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Marxisxts aren't the worst, as in recent decades they have accepted they were wrong. Only the deeply religious remain but they will die soon enough. Short-term-minded, gut-feeling, please-the-people-in-the-cheap-seats populists are the real danger.

Quadro-Action said:

If you will write more about political problems in your country USA I will do the same about those in Germany. It is a threat !!! he, he, he.

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You do that and I'll go along with Venezuela's and Colombia's. Now that's a threat!!

No, I won't. This place is for fun, delight and enlightement. Very little of that in V's and C's politics.

Hello Profou - I have had hope, all readers would find the joke between my message. But I think nevertheless, you have!

Dietrich

Bass seems directional to me as well. Sitting in the average auto tells me the bass is coming from the rear. There may be a frequency below which you cannot tell the direction, or hear for that matter, maybe only feel. The problem with the “sub”woofer reasoning is that an instrument has harmonics that extend into the frequencies that we can tell the direction. It is hard to distinguish the direction and type of instrument if the main note comes from one speaker and the critical harmonics come from another, on the other side of the room. I remember a certain speaker advertising that their coils were in line vertically, to promote acting like a single speaker, “a single point of sound”.

I’ve been a “wanna-be” audiophile ever since, as a kid, I heard a high end stereo setup with Klipsch speakers. I though, “I can even hear her breath”. I could distinguish instruments! Being from the poor side of town, the best I had known before was the AM radio in our ’60 Chevy. My quad, as a teenager, was Q8 player in my car (Smoke on the Water, Money, etc) and a EV (which I still have, somewhere) adapter with a cheap Olsen amp for the rears. I remember using a kitchen chair, so I could sit in the “sweet spot” while listening to “They Only Come Out at Night”. I’ve wanted to get back to the excitement of the “sweet spot” ever since. Just didn’t have the money or time. But I’m getting there.

Thanks!

Quadzilla said:

Lou is one of the pioneers of CD-4 technology, and he has written (in this thread) that he did not believe that any matrix technology would do justice to quad playback. For this reason, I would say that he has no intention of building matrix playback into his design, nor should he want to. Dedicated, single-format circuitry is always preferable to so-called "universal" types. SACD/DVD-Audio technology should have proven that.

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I understand that and I'm not asking for SQ / QS decoding to be put into the new CD-4 Demodulator.

What I'm asking is:

1. Is 100% decoding of SQ and QS recordings possible? Ever in any form machine or computer.

2. Is it theoretically possible to build an SQ / QS decoder with off the shelf materials that could match or exceed what the Tate models can do without it costing an arm and leg?

Because it is my understanding that to reverse engineer a Tate could cost possibly hundreds of thousands of dollars because of the chips.

What I'm asking for is Lou's opinion one way or another to my 2 questions.