Meteor: why is the DVD mono? (1 Viewer)

[TedD]

Damin:

Here is the blurb from Dolby's web site:

It says only that the CP100 was installed and used for the London Premiere of Tommy. It makes absolutely no claim that Tommy carried a Dolby Stereo optical track. In fact it was magnetic as indicated by the URL I posted.

Rob:

A Magoptical print is a print with the narrow width Foxhole perforations that was the standard for magnetic prints.

However rather than carrying a full silent aperture image that would result in a projected 2.55:1 AR, the magnetic stripes were laid over a conventional optical print yielding a 2,35:1 AR projected image, leaving half of the optical track available for use and reducing the optical track's SN ratio by 3db.

The result was a print that could be projected either in a 4 track magnetic equipped theater (provided the projectionist wasn't too lazy to thread up the magnetic penthouse and push a couple of extra buttons No don't laugh, I saw this happen a number of times back then) or with conventional optical sound in a theatre that was not equipped with 4 track magnetic sound.

It was primarily an effort to reduce dual inventory and booking foul ups that resulted in 4 track magnetic equipped theaters geting an optical print by mistake.

Ted

 

[Damin J Toell]

I'm not sure where the discussion is going at this point. Dolby installed the CP100 decoder for the London premiere of Tommy. Surely this wasn't just a random action; Tommy was presented in Dolby Stereo in that venue. I never said anything about the magnetic or opitcal nature of that presentation.

In your initial post, you seemed to indicate that Tommy was never presented in Dolby Stereo (first by stating that it failed to carry the Dolby Stereo logo and then by describing the pre-Dolby Stereo setup at the Colorado theatre at which you worked). My only point in response was that Tommy was indeed presented in Dolby Stereo at its London premiere. Is there disagreement on this?

DJ

 

[Mark Bendiksen]

For what it's worth, when I saw this film in Dallas during its original theatrical run it most definitely was not mono. Don't ask me why this sticks in my mind, but I distinctly remembering TONS of surround effects (especially as the weapons were heading towards the asteroid).

 

[Paul Linfesty]

Well, this engagement of TOMMY was officially marketed as "Quintaphonic Sound" (Quintophonic Sound in the film's credits). Dolby was the unadvertised NR used in this theatre. I guess by the logic used here, we should refer to the U.S. Quinatphonic Sound version as "DBX Stereo" since that was the NR used over here.

 

[Damin J Toell]

So far at least we can hopefully all agree the that the Dolby CP100 processor was installed specifically for the London Tommy premiere. Are you saying that the only purpose of the CP100 during that engagement was noise reduction? Or was it instead used for decoding the soundtrack? Dolby states that the very purpose of the CP100 was "for reproduction of Dolby Stereo magnetic and optical soundtracks". Was it not used for this purpose during the premiere of Tommy? If not, then why bother with the non-sequitur of installing a processor that was not being used for the purpose for which it was created?

If we assume that Dolby wasn't comprised in 1975 of fools who found it funny to pair up soundtracks and processors incorrectly, then it must be the case that the CP100 did more than reduce the noise on Tommy at the London premiere. So if Tommy had a soundtrack that was decodable with the use of the CP100 processor, and the soundtrack was encoded by/with/for Dolby for that very purpose, then it had a Dolby Stereo soundtrack. If the CP100 was designed "for reproduction of Dolby Stereo magnetic and optical soundtracks" and it was used for specifically the reproduction of the Tommy soundtrack, then Tommy must have had a Dolby Stereo soundtrack. Where's the controversy in this? I'm not defining the soundtrack based upon the company who provided the NR, but rather by the system by which it was designed to be decoded.

I don't really care how the film was marketed or what the credits said; the names used in marketing and credits have no necessary relationship to technological facts. They could've marketed it as "Not Dolby Stereo," and if it was indeed Dolby Stereo, the marketing name wouldn't suddenly change that fact.

DJ

 

[Paul Linfesty]

Yes. THAT is what NR means. Dolby uses an encoding/decoding method for NR. THat changes NOTHING of what I stated. The MATRIX used for creating the Rear Left and Rear Right channels was created by using the QS matrixing system, which at this time had not yet been licensed by Dolby, which is primarily why DBX had to be used for the U.S. release. (There were patents rights disputes over this).

 

[Damin J Toell]

So if the only purpose of the CP100 at the London premiere was to reduce noise, then the sound presented at that premiere must have been an undecoded matrixed mess, with the 4 matrixed FL, FR, RL, and RR channels not being properly heard at all by the audience and instead coming out as 2 channels. Is that the case? Or were the soundtrack matrices actually correctly decoded by the CP100? If they were, then much more than NR was performed by the CP100.

DJ

 

[Paul Linfesty]

As I clearly stated above, QS matrixing WAS used to decode the TOMMY soundtrack. Dolby had not yet properly licensed QS technology (and even when they did, it was only used for ONE matrixed channel, not two, as was used for TOMMY). So since Dolby had not licensed QS matrixing technology, this could NOT be considered a "Dolby Stereo" system in the sense that you are using (if you check the Dolby timeline, even they don't claim a matrixed surround track until A STAR IS BORN in 1976). DOlby NR was also used for 4-track mag, optical mono, and 70mm 6-track Todd-AO format films; all could be shown from the CP-100 unit and ONLY used the NR portion (and EQ) of the unit.

 

[Damin J Toell]

And what piece of equipment at the London premiere did this decoding? You said "Yes" earlier when I asked you if the sole purpose of the CP100 at the London premiere was NR, so presumably there must be another piece of equipment involved.

DJ

 

[Paul Linfesty]

It was a Sansui QS Quadraphonic decoder.

 

[TedD]

Damien:

The CP100 was used to apply Dolby A NR to the three (LCR) magnetic tracks and only used for that purpose.

You need to divorce in your mind the relationship between Dolby Stereo Optical tracks and the Dolby CP100.

The CP100 is merely a chassis with slots for cards that can do many things. For example it was used with 70mm mag prints to apply Dolby A NR to the individual channels, much like its use with Tommy. It also can contain a matrix decoder to properly decode Dolby Stereo Optical tracks into their respective 4 channels. By the way the decoder comes after 2 of the Dolby A NR modules that first apply NR to the two channels that will be decoded.


Of course not, the Center channel was a direct feed and the left and right channels were processed by the QS decoder into left front and rear and right front and rear channels.

It was an amazingly effective presentation.

Ted

 

[Damin J Toell]

Odd then that Daniel J. Sherlock writes that "Tommy was also the first feature to use the Stereo Variable Area (S.V.A.) Dolby Stereo format for some prints" featuring mono surrounds. A Dolby Stereo decoder must have been used somewhere for these prints.

DJ

 

[Paul Linfesty]

Damien,

NO ONE is disputing that there were some Dolby Stereo optical prints of this film (they played outside the U.S.). TOMMY was the first film to have some Dolby Stereo optical prints made for release (in the U.S. the first release was LIZTOMANIA a few months later). However, there was NO encoded surround track on these SVA prints, only the two-track left right (with "derived" center). The surround matrixing wasn't added to Dolby Stereo until A STAR IS BORN in 1976, per Dolby's own timeline (which, since you referenced, you must agree with).

However, you have been arguing exclusively on the specific London engagement of TOMMY, which used Dolby NR on mag tracks (which, by the way, IS an encoding/decoding system in itself).

BTW, I just checked your source, and it isn't clear that the author says that this specific film used a mono surround, but in case he did mean it, he would be wrong.

 

[Damin J Toell]

Only because a) I took TedD's posts to imply that Tommy had no Dolby Stereo exhibitions and b) I believed it to be a documented exhibition using Dolby Stereo. If the London premiere tangent was misguided on my part, I'm happy to be corrected.

DJ