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Info: article on Empire Strikes Back audio/70mm Dolby mix

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 (Edited)

A very dense technical article from Dolby Labs dating from 1981 has been reprinted on in70mm.com.
http://www.in70mm.com/news/2015/mixing/index.htm

Here is an excerpt concerning ESB:

Usually only a few 70mm prints are made for any film, and they play in New York, Los Angeles, Chicago and other large markets.2 In these cases, the large majority of stereo prints will be in 35mm stereo optical; hence, the importance of monitoring through the matrix. In the spring of last year, however, Bill Varney found himself in a unique position during the mix of The Empire Strikes Back: "Ben Burtt [the supervising sound editor], the crew and I decided that since we were going out with over 125 70mm six-track prints as our initial release, the best thing to do was to make sure that those prints were going to work and work well, and to deal with the Dolby matrix later for the 35mm secondary release. So we monitored the film in a discrete format all the way and, once the six-track was done, went back and put it through the 4-2-4 monitoring. We were pleasantly surprised, and had to do very little in the way of correction; the picture moved into the Dolby Stereo mode easily.

“The two areas where you have to be careful, and that are hard to predict, are the boom channels — speakers two and four — and, more importantly, the surrounds. The idea was to make the film work on the front speakers without any surrounds or booms at all. We mixed the film by recording on just channel one, three, and five. We then went back and added the surround channel and the boom on the other tracks. The advantage to that is that when the film goes out in Spearfish, South Dakota, and the surround speakers and boom channels are not working, at least you know as mixers and creative people that the film is going to play and play well — with just the front speakers working.”

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Well, that makes it pretty clear that TESB had a 4.2 mix in 6 track. I with OT had a search feature instead of relying on Google.

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I did some more research and reading and it seems clear that they adapted the TODD-AO 6 track format (L,CL,C,CR,R,S) to a 4.2 format (L,L-LFE,C,R-LFE,R,S) which they used for all thee OT films and the majority of 70mm films in the 80’s. Apocalypse Now was in a new format (L,LS/LFE,C,RS/LFE,R,S) where you could either have stereo surround or mono surround depending on your speaker configuration. What I found indicates they did not use that format for TESB or ROTJ, they stuck with the 4.2 mix. The ANH 1985 mix would also have been 4.0 matrix like the theatrical mixes. So the 1993 mix found in DE, Faces, and GOUT would have been the first 5.0 mix released followed in 1997 by the 5.0 Cinema DTS and 5.1 Dolby Digital for the SE.

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yotsuya said:

So the 1993 mix found in DE, Faces, and GOUT would have been the first 5.0 mix released followed in 1997 by the 5.0 Cinema DTS and 5.1 Dolby Digital for the SE.

Are you suggesting that the 1993 mix was constructed with stereo surrounds? Because it certainly wasn’t (and couldn’t have been) presented that way - those releases were matrixed 4.0 PCM all the way.

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It really depends on whether they intended it for a potential theatrical release or not. 90’s theatrical releases had two surround channels. Running even the 77 4 channel mix through a pro-logic decoder produces unique left and right surround even though we know that was not what they encoded. So what I’m seeing comparing the different mixes could be a decoding error, but other than adding in a few of the mono mix edits to ANH, making the mix with stereo surround seems like the most logical reason to make a new audio mix for all three films.

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5.1 AC-3 on LD came out before 94/95 (I found a review of a Pioneer LD player with AC-3 RF output from late in 1995 and the Star Wars SE LD set had AC-3 5.1 audio in 97). It would make sense if the 93 mix involved remixing the surround to be two channel. The resulting Dolby Stereo mix would be downward compatible for 4 channel systems and be compatible with the current 5.1 systems then in theaters. I just finished adjusting the audio levels of the trilogy from the theatrical release to the 93 release and the 93 mix surround didn’t have the same signature that the theatrical and 85 did. There were a lot of subtle differences in the mixes so I may just have been imagining it, but it very well could be the first 5.1 mix of the trilogy. The audio levels seemed a lot closer to the 97 SE - what I was using to set the channel audio levels.

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yotsuya said:

5.1 AC-3 on LD came out before 94/95 (I found a review of a Pioneer LD player with AC-3 RF output from late in 1995 and the Star Wars SE LD set had AC-3 5.1 audio in 97). It would make sense if the 93 mix involved remixing the surround to be two channel. The resulting Dolby Stereo mix would be downward compatible for 4 channel systems and be compatible with the current 5.1 systems then in theaters. I just finished adjusting the audio levels of the trilogy from the theatrical release to the 93 release and the 93 mix surround didn’t have the same signature that the theatrical and 85 did. There were a lot of subtle differences in the mixes so I may just have been imagining it, but it very well could be the first 5.1 mix of the trilogy. The audio levels seemed a lot closer to the 97 SE - what I was using to set the channel audio levels.

Clear and Present Danger was the first 5.1 DD title

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Nah, the 1993 versions are mono surround only.

The one for the first movie was made by using the four main channels of the 70mm mix (L, C, R, S), combining it with additional bass derived from a separate sfx-only master, and then adding new sound effects on top of it in certain places. The mono surround of the 70mm is presented as is with no modifications, aside from some of the new additions also appearing in the rear from time to time.

For ESB, they did not use the 70mm version, but instead took it from the original four-track master conformed to the 35mm edit, adding in bass using the same method. Minor differences exist between this version and both theatrical mixes, but they are very small and the overall sound is very close to what the 70 would have been (when the film was slightly re-edited for 35mm, the entire mix was not re-done but only given minor modification, mainly for the new edits). Again, the surround effects are mono.

Unlike the other two, RotJ '93 is a new mix from multitrack stems, and so does not reflect what the 70mm would have sounded like except in the general sense. However, it was done in the same way, and again has mono surrounds. Since these were only made for home video viewing and intended to be decoded by Dolby Prologic (stereo surround decoding did not yet exist in any Dolby product), there was no reason to do them in any sort of 5.1 style. No 4 or 5 channel version of the 1993 versions was ever made; they were matrixed stereo digital mixes only.

When decoded with Prologic II or other stereo-surround capable algorithms, it is true that these mixes will show separation between the derived surround channels. However, this content consists only of crosstalk from the front. The actual surround effects themselves are mono; they are equal in level between both rear channels. Discrete channel 70mm versions would not have had such crosstalk, so a decoding scheme that allows for the least perceptible amount of it will most accurately reflect what the source would have sounded like prior to matrix encoding.

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Everything I have seen says that for Star Wars the 70mm and 35mm stereo tracks had the same 4 track master. No differences have ever been reported except for the two LFE channels that rounded out the 70mm’s 6 tracks. So it wasn’t specific to the 70mm. The 85 mix is identical to the 77 mix except for Threepio’s extra line. The 93 version has the same base, but more additions.

For TESB, the 70mm version was done before the movie was really finished. That makes 2 movies in a row like that, though for Star Wars they didn’t change the 4/4.2 track masters… they created a mono mix instead. So the finished audio is the 4 track master used for the 35 mm release. This was the first time a lot of these edits had been heard outside the mono mix. There was nothing new and plenty of omissions. I have no knowledge of the ROTJ 70mm presentation.

To achieve a proper mix, the new edits would have at least had to be added to the 4 track masters and then rematrixed. From a topic that came up a number of months back relating to the 1985 CBS/Fox release, it is not a difficult thing to rematrix the audio from the 4 track masters.

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digitalfreaknyc said:

yotsuya said:

5.1 AC-3 on LD came out before 94/95 (I found a review of a Pioneer LD player with AC-3 RF output from late in 1995 and the Star Wars SE LD set had AC-3 5.1 audio in 97). It would make sense if the 93 mix involved remixing the surround to be two channel. The resulting Dolby Stereo mix would be downward compatible for 4 channel systems and be compatible with the current 5.1 systems then in theaters. I just finished adjusting the audio levels of the trilogy from the theatrical release to the 93 release and the 93 mix surround didn’t have the same signature that the theatrical and 85 did. There were a lot of subtle differences in the mixes so I may just have been imagining it, but it very well could be the first 5.1 mix of the trilogy. The audio levels seemed a lot closer to the 97 SE - what I was using to set the channel audio levels.

Clear and Present Danger was the first 5.1 DD title

Well, the first US LD release. Pioneer had players out at least a year before that and I’m sure there was plenty of content to take advantage of it (since Pioneer made the discs as well as the players), though it might have all been Japanese releases or programs.

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Everybody mixed in matrixed form for years and it took several years for 5.1 to really take hold. Thus many mid 90’s films still have very good if not better 2.0 surround tracks as that was what got the most attention-especially if theaters hadn’t paid for and new hardware or if the DD 5.1 track went out which it often did.

On the home front it was all about mixing in matrix for ProLogic with no real frills. The 93 mixes are fantastic for the time and for the most part seem to at least make an attempt to stick to the original efforts in spite of the new sound effects here and there.

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I was checking out the 97 SE DTS and DD/AC-3 tracks (for ANH) and I’m wondering just how much effort they put into the surround mixes. It has a very similar pattern to the older mixes when they are dematrixed using ProLogicII. I also noticed that the surround channels are identical for the two different 97 mixes. The only differences in the mix is that the DTS is 5.0 and the DD/AC-3 is 5.1 (there is no cutoff below 120 or 80 in the surround tracks but the DD has a discreet LFE track that is completely unique and hopefully derived from the original 70mm LFE tracks).

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Somewhat off topic but I still say matrix 2.0 is still better than dd 5.1 due to the increased bitrate per channel and a little crosstalk doesn’t bother me at all, I wouldn’t even notice it. Obviously not comparing it to dts 5.1, but to me a 2.0 dolby track (at a reasonable bitrate of about 384 kbps) that’s matrix encoded is the next best thing if you can’t listen to dts tracks.