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In the space allotted to the conventional mono optical soundtrack are two soundtracks that not only carry left and right information as in home stereo sound, but are also encoded with a third center-screen channel and-most notably-a fourth surround channel for ambient sound and special effects.

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quote: Ken Lackner

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Yet, if there was only one track, would such a print be playable on today's readers?

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quote:

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Titles in this Series

Film Gauges and Soundtracks
Widescreen and 3-D Film Formats
Motion Picture Colour Processes
Motion Picture Systems for Special Venues and Theme Parks
Video Tape and Recording Formats
Current Film Formats
SFX Chart 1 Photographic & Digital compositing
SFX Chart 2 Animation & Computer Imaging
SFX Chart 3 Special Effects (NEW)
Video Recording Techniques
How to order

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quote:

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Illustration of film gauge and soundtrack chart

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quote: Ken Lackner

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Now that some of you have confirmed that such older tracks are playable on today's readers, my question is, How? Wouldn't the solar cells have to be different, and/or wouldn't the processor have to treat the tracks differently?

On a related note, do today's readers contain one solar cell, or two (one for each track)?

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quote: Stephen Furley

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did anybody ever propose a system which recorded three channels of stereo sound, using the three layers of colour print stock?

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Yes, John Mosely (sound designer of Quintaphonic Sound for TOMMY) designed a multichannel soundtrack based on the three emulsion colors, each color recording a single channel. It had many drawbacks as the track had to be illuminated quite brightly because filters had to be used to separate each of the colors, with each filter depleting the amount of light available to the cell. Increasing the exciter lamp intensity caused other problems with flare and distortion. John P. may have an SMPTE white paper reference on this system, which I believe was called KenTech, or perhaps that was Mosley's company, I am not sure. But my recollection is that the company did produce a working prototype, and may even have printed a few test reels of a stereo feature with the system but, unfortunately for them, Dolby was working on its system at pretty much the same time and trumped the KenTech color approach.

The really interesting thing about the KenTech colour approach is that it would be able to contain a DESCRETE surround channel rather than a matrixed one. The only processing that would be necessary would be to sum the left and right channels to derive a phantom center. But the surround would be a channel all its own, which means the sound mixer would have the latitude he had with magnetic sound and now again with digital, and that is, he has a much greater latitude in placing dialogue anywhere he wants across the stereo soundfield without worry of it swinging around into the surrounds. Once again he could mix directionally for dialogue placing the voice with the image as was the practice with almost all the 70mm multichannel mixes.

Here's a question: years ago I recall that around the time Dolby introduced it's optical stereo sound, there was a rash of 16mm projectors that came on the market touting stereo sound capability. Evidently they were able to play SVA tracks, if such things were produced. I spoke to Ray Swank at the time and asked if any of the studios were releasing their 16mm titles with stereo tracks. He said there was never any move in that direction. Yet, I knew a projectionist who worked at the army base theatre in Fort Hamilton in Brooklyn and he said that when the army stopped acquiring their films on 35mm and went to 16mm, they installed a Dolby CP50 and I believe he said an Elmo pedestal projector; he also insisted that the 16mm prints that were set to the base were stereo prints and they were encoded with surround. He said they had [STEREO] printed in the soundtrack just like 35mm prints and you were supposed to selected Format [04].

Now these may have been prints especially struck for the army (the armed forces network bought all their own prints), but I have never seen a bilateral stereo soundtrack on any 16mm print. Has anyone else? I would think that if such prints were struck, they would eventually wind up in the hands of collectors, but I have never come across one. I also don't understand that if stereo encoded soundtracks were viable for the army, why wouldn't the studios just use the same sound negatives for the non-theatrical market? I have a feeling this is a reel myth.

BTW, the KenTech colour stereo system would have worked as well on 16mm prints.
 

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Posted by Richard Fowler (Member # 893) on 07-18-2004, 09:01 AM:
 
Colortek was the system and I heard the demostration in the early 1980's at a Los Angeles SMPTE convention. It was excellent. The conversion was installed in a standard Century soundhead. Concern about film processing issues and the push to Dolby Stereo analog tabled the system.
 

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Posted by Michael Schaffer (Member # 1204) on 07-18-2004, 09:10 AM:
 
The analog tracks probably filled the whole space available on the film, so I guess that might have made up at least partially for the light loss described by Mr Angel. But I guess it wasn't compatible with conventional playback systems at that time, be it mono or Dolby Stereo. So that must have made it even more unlikely to be introduced widely.
 

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Posted by Gordon McLeod (Member # 33) on 07-18-2004, 10:51 AM:
 
The navy also had several theatres with Elmos and Prevosts with stereo cells connected to CP50's and KT800's
AMC attempted a 16mm program with eastman 25's and Kintek systems as well
 

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Posted by Ken Lackner (Member # 1002) on 07-18-2004, 12:15 PM:
 
Stephen,

There were three articles that I could find on Fantasound at the Widescreen Museum. None of them had a pic of the actual soundtrack. Do you have an exact link?

If modern cinema processors contained the right format, could they play a push-pull track on today's split cells? I don't see why that would have held back the implemenation of push-pull tracks, because obviously soundheads had to be upgraded once dual bilateral tracks were introduced.

I just looked at all your pics on the 16mm thread. ( Link in case anyone else is interested.) Very interesting! Would each of these formats require a different soundhead modification? That must have gotten expensive. I never realized there were so many different types of variable area tracks. I thought they always looked like the tracks we have today.
 

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Posted by Steve Kraus (Member # 476) on 07-18-2004, 04:41 PM:
 
Comtrak circa 1981 used a set of snake tracks to carry discrete LCR alongside an Academy mono track that is about the size of a single trace of conventional dual bilateral tracks. By "snake" we mean a clear line against black which varies in position--that is, it wiggles around, but does not change in width so does not have an effect on mono playback on conventional soundheads (they would have to turn up the fader not unlike what happened with the mag/optical track where the C channel mag stripe overlayed half of the optical track).

Playback would be via a CCD scanner.

Just outside the area scanned by a normal soundhead on the picture side was a straight line which acted as a reference point for playback of the snake tracks (counteracting film weave going through the soundhead or during printing).

Beyond this beside the picture was a surround track which could be either a snake track OR something resembling a bilateral track but with differing sides for spit surrounds with modulation in the form of sum and difference. (Add the sides for Left Surround, subtract for Right Surround).

Finally, on the outboard edge of the track (and again, outside the normal pickup area) was provision for a PCM data track.

Description based on article in SMPTE Vol.90 Number 9 (September 1981), the same issue which described the Dolby CP200.
 

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Posted by Stephen Furley (Member # 1277) on 07-18-2004, 07:16 PM:
 
Ken, I can't find the picture I was thinking of, I'm fairly sure it was in the Widescreen museum somewhere, I remember that it had that mottled look of an old wet-toned electrostatic copier that the other Fantasound documents had. There's so much information in there, it may have been in another article, one not just about Fantasound.

I've found another picture of the sound film, it's not as good a picture, the film edges and perforations are obviously drawn in, but I think the tracks are genuine, though touched up somewhat. Anyway, it gives a reasonable idea of what the track looked like. The left-hand track is the easiest to see the detail of.



This picture was taken from the booklet which Dion Hanson produced to acompany his 'Fantastic Formats' lecture. I hope he doesn't mind me using it. (Excellent lecture, Dion. )

Those pictures in the 16mm sound formats thread are only some of the more common formats, there have been others, though most of them are fairly minor variations of one of those shown. The various push-pull tracks, and something called a density squeeze track are the main missing ones. The density squeeze track was a variable density track where the width of the track was reduced during quiet passages, as a form of ground noise reduction.

All of the tracks shown can be played with a standard optical sound head, without requiring any adjustment.

You wrote:

quote: Ken Lackner

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If modern cinema processors contained the right format, could they play a push-pull track on today's split cells? I don't see why that would have held back the implemenation of push-pull tracks, because obviously soundheads had to be upgraded once dual bilateral tracks were introduced.

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quote: Stephen Furley

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I don't understand what you're saying about upgrading soundheads; no upgrading was necessary to play Duo-bilateral mono tracks.

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quote: Frank Angel

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John P. may have an SMPTE white paper reference on this system

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The Colortek Optical Stereophonic Sound Film System

By JOHN MOSELY, KEITH O. JOHNSON,
and DAVID E. BLACKMER

Colortek is an optical sound system rendering four separate unilateral variable-area audio tracks and a central control track, all within the area of the present monophonic variable-area and variable-density soundtrack location as defined by American National Standard PH22.40-1967. The innovative design of the system employs, as a sound reader, a charge-coupled-device scanner (CCD scanner) and applies video technology to the read-out of soundtracks. It scans the four soundtracks transversally at 10 MHz, resulting in a CCD frame rate of 40 kHz, as the tracks pass longitudinally at the normal speed of 24 film frames/s (457.2 mm/s) through the sound reader. The electronic drive of a Westrex light valve has been modified to obtain the new soundtrack configuration. No ground-noise-reduction device or circuit has been incorporated, because the design of the CCD scanner suppresses ground noise almost completely. The soundtrack may also be reproduced on projectors with a normal optical sound head. However, due to the use of electronic companding and to the lack of ground-noise suppression, the reproducing electronics should be modified to reproduce the four-track format correctly. This format can be reproduced monophonically as well as stereophonically. Both the frequency and dynamic ranges of the recording light valve have been extended to achieve faithful transfer from the magnetic to the photographic printing medium and faithful reproduction in the theater. By the use of matrix encoding, the system can be extended to accommodate six separate channels of sound for surround sound effects in 35mm theatrical presentation. The narrow center control track serves several purposes: (1) it enables the CCD scanner to recognize and compensate automatically for any side weave of the soundtrack; (2) it serves as an image-spread monitor for correcting, within limits, distortions caused by image spread; (3) it can be used to trigger special sound effects or auditorium speaker groups as encoded on the control track; (4) it also can be used for automatized general theater operation. A specially designed compander completes the system.

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quote: Peter Mork

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On the subject of tracks that used emulsion colors to separate channels, I remember reading somewhere that Popeye (1980) used a system of that sort. The only reference I could find via Google was a note that this film was the first release in Vistasonic sound, but didn't describe what it was. Anybody know?

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quote: Martin Brooks

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Popeye was released in Vistasonic, a system developed by Paramount, but that it was a 4-track mag system.

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quote: Sam D. Chavez

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The Vistasonics I remember was used on another picture before Popeye and there were a number of experiments around the SF bay area.

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1980: 'Popeye' becomes the first film to use the 'Vistasonic' system

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Hello, and welcome to the SpannerWorks. I have always been fascinated with the reproduction of film in the home. As a result I created the SpannerWorks, a site dedicated to home theatre and DVD technology and, to a lesser extent, the technology used to present film theatrically.
Time permitting, I also write DVD reviews of Region 4 discs (Australia and New Zealand) and the occasional article on DVD technology. I have also included a selection of links to some online resources I've found useful over the years. These should provide an introduction to those seeking information about emerging home theatre digital technologies. Feel free to contact me if you have any comments, questions or suggestions to make regarding this site or its content.

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Posted by Mitchell Dvoskin (Member # 751) on 07-21-2004, 01:57 PM:
 
Popeye was indeed release in a strange 4 track optical system, that looked as if it had 4 seperate tracks in the regular optical soundtrack area. I remember that we were accidentally sent one of these prints, and had to get a replacement normal print do to low volume and a loud buzz when played though our Dolby cell.

I am unaware if this system was every used commercially.

/Mitchell
 

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Posted by Gordon McLeod (Member # 33) on 07-21-2004, 02:43 PM:
 
the print of popyee at the Hollywood theatre in toronto was 4 track mag and was very hissy to boot
 

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Posted by Steve Kraus (Member # 476) on 07-21-2004, 07:01 PM:
 
The Colortek must have morphed into the Comtrak system I described earlier as the article in SMPTEJ was by Mosely and Johnson and they say it overcomes the objections to the earlier system. The authors were said to be with a company called Colortrak, Inc.

Sample Comtrak track:



Top to bottom: data track, LCR, mono VA, surround. Surround is shown as a snake not a dual unilateral stereo surround which was also described.
 

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Posted by Stephen Furley (Member # 1277) on 07-22-2004, 01:07 AM:
 
Do you know if the 'L' track, for example, was actually that, or a difference signal, (L-mono), similar to the way that component video is done? I have read articles which suggest both; maybe they tried it both ways.

Did they give any suggestion as to what the data track could be usedfor, and what the data rate was.

The BKSTS wallchart, at least the older version of it which I have, but probably the current one as well, has a frame of Comtrak, but the tracks are so narrow that it's difficult to see any detail.
 

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Posted by Michael Schaffer (Member # 1204) on 07-22-2004, 06:12 AM:
 
I had pictured the Colortek system as using the whole width of the available space for just one channel, but then have one channel in each of the color layers which would be read separately using color filters. Apparently I was mistaken!
 

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Posted by Leo Enticknap (Member # 534) on 07-22-2004, 06:54 PM:
 
For info, chapter and verse on Fantasound can be found in W.E. Garity & J.N.A. Hawkins, 'Fantasound', J/SMPE vol. 37 (August 1941), pp. 127-146.
 

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Posted by Ken Lackner (Member # 1002) on 07-30-2004, 04:37 PM:
 
Some more questions, as I've been doing more reading and more thinking.

If you get a print with an Academy mono (Format 01) track, would it be necessary to play it in Format 01, or could you use 04 or 05? Since the two tracks are identical, I don't see that there would be any issues with improper surrounds being decoded. Everything should be sent to the front speakers. The only issue I could think of would be improper noise reduction. If the track was not recorded with any NR, would there be any adverse effects if you were to play it back with NR (04 or 05)?

My next question pertains to Format 03. My theater has CP55's. I read the enitre instillation manual. It says that most Dolby Stero prints were (and are) mixed with a surround channel, except for a very few of the early ones. In the troubleshooting section, it says that if you are having problems playing one of these early prints in Format 04 (if improper surronds are being decoded), to play it in 03, which will eliminate the surrounds. So what do you do if you get one of these prints and you have a CP65 or a 650?, which do not include Format 03?

(The CP500 includes Format 03 as one of the formats you can choose when assigning custom formats. Form some reason, at least according to the manual, the 650 does not. Anyone know why?)
 

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Posted by Richard Fowler (Member # 893) on 07-30-2004, 05:21 PM:
 
Regarding older mono tracks in the USA; they where recorded with the "academy curve" which would effect playback quality. Mono track azimuth may not be perfect and may have undesireable on the surrounds.
 

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Posted by Leo Enticknap (Member # 534) on 07-30-2004, 05:39 PM:
 
03 wasn't used very much. The only film which I know for sure was released in 03-encoded prints was Lizstomania.

Vaguely related to which, I found that if you get a variable density track with less than ideal contrast (i.e. it's flat, and so there's a hell of a lot of ground noise playing it normally), playing it in 02 does an amazing job in boosting the s/n. The Dolby manuals threaten the death penalty for using 02 on anything other than a noise reduction-encoded mono VA print, but my purely subjective opinion is that in many cases, it makes density tracks sound a lot clearer.
 

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Posted by Steve Kraus (Member # 476) on 07-30-2004, 05:51 PM:
 
In addition the level would be too high although obviously you could bring the fader down. Dolby prints are recorded at a slightly lower level than mono as they trade off some of the improved noise floor for more headroom (by keeping the average level lower there is more room for loud sounds like explosions etc. without clipping--the modulation on the track can only get so large). A is lower than mono. SR is lower still.

If you ever did encounter a Dolby A - No Surround print (sorry if I skip over the format numbers; it's just plain silly) just play it in Dolby A and turn off the surround amp(s). (Unless of course you get a chance to audition it and find it sounds better with that bit of ambience in the surrounds).
 

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Posted by Ken Lackner (Member # 1002) on 07-30-2004, 06:00 PM:
 
What is Format 02? I've never seen this described or even mentioned in any of the Dolby manuals I've read.
 

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Posted by Steve Kraus (Member # 476) on 07-30-2004, 07:58 PM:
 
Dolby Mono (A-Type)

High fidelity (wide range, not Academy-curve limited) with Dolby A-Type noise reduction but not stereo. So...noise reduction on....Academy filter off...and matrix should be told to sum Lt & Rt into C.

This is the original Dolby optical sound format although I believe it was more a UK and possibly Canadian thing than US. Dolby Model 364 contained a single Cat.22 A-type NR card while Model E2 contained a single Cat.64 house EQ card. The original Cat.64's also held a separate circuit which offered an adjustable HF gain like you now have on CP preamp cards...sometimes called slit loss correction. So the signal could go through that before going to the 364 for NR then back to the E2 for house EQ. These are both 1 rack unit high boxes and many found use later on as add-ons to the CP100 system.

Woody Allen still uses the SR version of this format.
 

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Posted by Ken Lackner (Member # 1002) on 07-30-2004, 08:03 PM:
 
So essentially it's a track with A-type NR applied, but the mix is mono, correct? How many titles used this format? Why is Format 01 included on modern processors, but 02 isn't?

When playing current Woody Allen titles, should they be played in Format 05? It doesn't really matter what the mix is (mono, stereo), as long as the correct noise reduction format is applied, right?
 

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Posted by Steve Kraus (Member # 476) on 07-30-2004, 08:12 PM:
 
According to the Larry Blake book about 10 films were released in Dolby Mono. That was from a 1981 article and obviously doesn't count subsequent titles of which Allen may be the only known user but there could be others.

Yes, play the current films in SR (or digital of course). The NR, level, and Academy filter OFF is the most important thing. If things are in reasonably good adjustment the matrix will steer sound to the C channel just fine. If there's a problem you can always kill the other amps.
 

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Posted by Frank Angel (Member # 248) on 08-01-2004, 12:18 PM:
 
I don't quite understand if we are talking about a currently released title released with SR encoding, why it would be necessary to make any mention at all as to whether the print was mixed MONO or STEREO. Wouldn't it make more sense to avoid confusion in the booth by projectionists who are going to see the word MONO in the leader and go "DUH"? Seems it would make more sense to simply let it play in the standard SR stereo format. The processor in the stereo + surround mode will care not a wit if the audio mix happens to be mono. If the A-chain is correctly aligned, it should play a stereo track with mono content without incident, with the L & R summed to the center and with hardly anything coming from the left and right and nothing in the surrounds. If the system is slightly out of alignment and stuff is bleeding into the surrounds, as you said, those amps could always be turned off if needed (or better yet, call in a service tech to realign the system). You could even turn off the L & R channels if you absolutely have to, although a mono signal coming out of all 3 screen channels has never sounded objectionable, IMHO. But in a well calibrated system, this should not even be an issue.

Is it really relevant to the projectionist to know if what is on the soundtrack is recorded in mono or stereo? Or am in missing something here? I just think you would be asking for trouble by saying it has to play in SR but in MONO and without the Academy curve (if it is mixed in MONO, it will de facto play back as mono); the Academy curve is would become a real issue in older processors. The CP50, and 55 don't have that format configuration readily available, correct?
 

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Posted by Ken Lackner (Member # 1002) on 08-01-2004, 01:34 PM:
 
So Woody Allen films are technically SR, right?
 

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Posted by Leo Enticknap (Member # 534) on 08-01-2004, 02:24 PM:
 
The last one I showed (Small Time Crooks) was, and it also had Dolby digital through the centre channel only (i.e. all the others carried no signal, so you might as well turn their power amps off during the show).
 

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Posted by Frank Angel (Member # 248) on 08-02-2004, 03:12 AM:
 
Well, why bother turning of the amps at all? Surely not to save electricity. Besides, if you are playing digital, there is no chance of errant bleed into other channels. If there is no signal recording in all but the center channel, the other channels will just be silent, no worry about bleed. On the other hand, turning off amps would be quite problematic when the trailers are run.

With SR, there could be a slight bleed into the surrounds, but as I said, if your system is properly aligned, that should not be a problem -- the delay masks that.
 

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Posted by Leo Enticknap (Member # 534) on 08-02-2004, 04:10 AM:
 
In my case, it was simply to cut down on the heat being kicked out by their fans in what was a very hot booth.
 

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Posted by Frank Angel (Member # 248) on 08-03-2004, 01:08 PM:
 
Cool.
 

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Posted by Steve Scott (Member # 630) on 08-03-2004, 01:46 PM:
 
I use format 03 for Moviefone ads in our Dolby auditoriums. My CP500's like to matrix some HF dialouge peaks into the surrounds in 04 or 05 with those spots, and it leads up to the feature material better as the surrounds are added after the spot.
 

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Posted by John Pytlak (Member # 331) on 08-04-2004, 07:42 AM:
 
Dan Sherlock of Media Technology Consulting asked me to post this:

quote:

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I noticed the discussion about "Film Sound - history and technical details" on the film handler's forum at film-tech.com. A comment was brought up by Frank Angel about a process he believed "multichannel soundtrack based on the three emulsion colors, each color recording a single channel." Folks on the forum thought it might have been the Colortek system by John Mosley. I believe what he was referring to was an experimental variable-hue system developed by Petro Vlahos rather than by John Mosley (who did read the paper about the process at the "Film 75" conference in London.) The system did not use "each color recording a single channel" but rather recorded a push-pull style signal that varied the hue between red and cyan. Three side-by-side color tracks were used to give a three track sound system. The system is described in the September 1975 issue of American Cinematographer, which ironically also had an article describing the development of the Dolby Stereo optical print format. Of course, the variable hue format was incompatible with regular sound readers and required dual-inventory prints, which was part of what ensured its lack of success.

By the way, just to introduce myself -- I am the author of the "Wide Screen Movies Corrections" document that is on the "Tips" area on the film-tech.com web site. That document describes the many errors in the book "Wide Screen Movies" by Robert E. Carr and R.M. Hayes. I am chasing down some additional details and hope to release an updated version in the near future. At the present time, it is about 50% larger than the older version (which says something about how many errors there were in that book.) Anyway, I have been a "lurker" at the film-tech.com site for quite a while now, and since nobody seemed to clear up the "color modulated" subject, and since you have a good historical background on the subject, I thought I would pass on this info to you.

-----------------------------------------
Dan Sherlock
Systems Engineer
Film Format Historian
Member, SMPTE & BKSTS

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quote: Ken Lackner

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So Woody Allen films are technically SR, right?

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quote: Martin Brooks

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Popeye was released in Vistasonic

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quote:

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The Vistasonics I remember was used on another picture [besides] Popeye and there were a number of experiements around the SF bay area.

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quote: Martin Brooks

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My notes do say that it played at five theaters in that format in NY, Los Angeles and Chicago.

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quote:

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I am unaware if this system was ever used commercially.

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