Titanic (1997): Cinema DTS sound mix-Prepping for the Print…One Hopes.

[spoRv]

I was not aware that DTS started attenuating decibels in the surround channels for later titles.

Nope, the contrary is true; first titles had +3dB surround channels - don't know if all, or just some, and until when, but it was discussed somewhere on the web. Probably DiscLord (r.i.p.) knew it perfectly, and maybe he wrote something about this on lddb.com forum IIRC.

[alexp120]

alex, there is a whitepaper on cinema DTS and it's properties.  I probably have it somewhere but you can also use google to dig it up.  It would probably be informational to you.  Also, hairy_hen over at OT has done some great work explaining audio stuff like this.

I do have that.  And I read this from hariy_hen over at the OT:

The surround channels most definitely need to be attenuated by 3 dB in order to provide proper balance.  I explained why in a post in the other DTS thread, which I will copy/paste into here:


hairy_hen said:

Theatrical sound systems are calibrated such that a -20 dBFS pink noise tone will play at 85 dBSPL from the front left, right, and center channels, while the rear channels measure at 82 dB.  This is to maintain backwards compatibility with Dolby Stereo analog tracks, which have a monaural surround capability rather than stereo rears.  In Dolby Stereo, the entire array of surround speakers is treated as one unit, which together measures at 85 dB.  So when 5.1 came along, they essentially split the existing surround in half, with the left and right each playing the same signal at 82 dB instead.  When heard together, the combined result of all the surround speakers is at 85 dB as it should be.

What this means is that because the surround channels in movie theaters and post-production stages are deliberately set to play back at a lower level than the front channels, the content of the surrounds will end up being 3 dB louder than it otherwise would be.  The mixers will set the level of the surround effects to sound 'correct' to them on the system they are listening on.  When this is played on home theater systems, which are calibrated with all channels set equally to 85 dB, the surrounds will end up being 3 dB too loud.

Because of this, a theatrical mix played on a home system must have the rear channels lowered by 3 dB in order to sound the way the mixer originally heard it.  5.1 encoders typically have a selectable option to do this automatically when creating the files for home use, but this was not always the case.

Note that calibrating the surround channels at 82 dB instead of 85 applies to all theatrical 5.1 formats, not just DTS.  Playing the same signal out of each surround results in a doubling of the acoustic power, which increases the total level of a mono signal by 3 dB.  It's the same thing that happens with the phantom center in a stereo mix.  Double power results in a 3 dB boost, but this must be distinguished from doubling voltage, which is what occurs when summing electrically—this creates a level increase of 6 dB for phase coherent signals.

So the surround channel calibration is easily explained when looked at in this manner.  When it comes to the LFE channel, however, things become considerably more complicated.  I tried to figure it out a while back and couldn't quite arrive at a satisfactory explanation for everything in the DTS system manuals, because we have no idea exactly what the analog chain inside their hardware actually is.  I am going to go back and open my Pro Tools session for the '97 SE DTS again, so I can take another shot at giving you guys an exact method to reproduce the LFE calibration and crossover.

Which is why I have been lowering the gain in the surround channels in the first place.

[alexp120]

Just to report:
I have half of the reels completely sync'd to the Blu Ray (that is 5 out of 10 reels).  Each sync'd reel is in 16bit/48K with sound levels untouched.

The final days of Xmas are coming so I have better break from the labor end of this project, now.  I'll still check-in here to respond to queries.

With regard to my sound level processing, it just occurred to me that there are home theater receivers/amplifiers that will compensate the drastic changes in sound levels--from very low to very loud--from a source.  So, I am completely on-board with leaving the sound levels of the sync'd files intact.

[alexp120]

A thought has occurred to me that I need to mention.

To remind everyone, the production of this picture was paid for by Paramount and Fox.  This entitles the studios to distribution rights, so, the territories in this world were divided between them.  All the territories received the same 9 reels—reels 2 through 10.  However, because the two studios have distribution control over certain countries, two slightly different versions of Reel 1 were created. One difference is the studio logo clip that precedes the start of the film—some parts of the world saw the Paramount logo clip while the remaining parts of the world saw the Fox logo clip. After the studio logo clip, the content of the film in reel 1 is the same in both studio versions, however, there is one more difference between them.  I’ll get to that in a moment.

On the Cinema DTS CD-ROM disc, there is audio for both versions of reel 1.  While Paramount reel has no sound over their studio logo clip, the Fox reel has the popular fanfare music over their logo clip.  Now, according to the audio files, the Fox reel runs 4 seconds longer then the Paramount.  I’ve been sync’ing the audio to my own Paramount Blu Ray rip.  I would image that there are members here that may have a copy of the film with the Fox logo clip.  How should I address the release of the audio to accommodate both versions?

And what about the print of the film that the OT member purchased?  What studio logo clip does it have?  That, too, will have to be addressed when the time comes.

[jerryshadoe]

Yup, those original levels on the Cinema DTS sound much better and I'm glad you ended up going that route. Good luck to you with your project

[Stamper]

That's weird on my pioneer amp set up, when you choose the S for small configuration for the room, it attenuates the surrounds by -3db. The result is you can't hear anything from the surround, so I had to pull them back to 0db like all the other speakers.

[Jetrell Fo]

I am glad to see this is turning out nicely. As for the 2 different reel 1 issues, maybe making 2 different mixes, 1 with each opening, would be the best way to go.

[alexp120]

Hi, all.

I’ve finished sync’ing and piecing together all of the audio reels into one 6-channel sound file.

I’ve created two audio files of the film--one, the Paramount-distributed version and the other, a Fox-distributed version.

With some help, I’ve made arrangements to present these Cinema DTS mixes in DTS-HD MA bitstream.  

About the Fox-distributed version: I do not have a copy of that.  So, I just used the audio file of the Fox version for Reel 1 and sync’d it to my Paramount-distributed copy of the Blu Ray, since the content of that reel is the same after the one logo clip from either of the two studios.  The duration of that audio stream may be either shorter or longer than your copy so audio delay may have to be applied.

By this time, you all should have a serge of generosity in uploading a copy of the Fox-distribution version for me.     Thanks for that, but hold-off on it.

I’ve worked out a scheme to help you all get a good sync of this audio to your copy of the movie, preferably at 23.976fps.   And to make sure this plan works, I'll need volunteers to check-out my sync job, so send me a PM.  Please specify which version of the audio you’d like.

You’ll receive a PM back from me with the link to the bitstream along with instructions and screenshots from the movie. Each screenshot will have a frame number and a position timestamp.  Basically, you’ll be checking to see if the frame number on each of the screenshots matches the frame number on your media player. If not, audio delay would have to be applied to your copy and you need to know how much.

I’ll be reviewing my sync-job tonight.  If all goes well, you’ll be getting a PM response from me tomorrow.

Your feedback is most appreciative.

Thanks for your show of support.

[alexp120]

Happy New Year to all.

I reviewed my sync-job and I feel that it came off well.  I’ll upload the DTS files in folders early tomorrow morning.  I’ll be taking PMs from volunteers, now, to go over my work. Again, please specify which stream that you want.

When I checked my work, I didn’t look at the film from start to finish without interruption.    I just wanted to spot-check the scenes with dialogue so that I’d know if the sync is good, so, for my convenience, I created an OGM chapter file where I placed markers on just those scenes throughout the film.  I figure if those scenes are in good sync, the rest of the scenes would be alright.  If you want to avoid the outstanding scenes, but just want to check the lip-sync, then use my chapter file.  I’ll include it in the folder.  

Up until this project, I’ve haven’t seen this film, even in small parts, since I saw the re-release in 3D in 2012…and that was the first time I’ve seen the film theatrically.  The very first time I’ve seen it was on DVD via a 42-inch screen TV.  I’ve liked the film and I try not to watch it too often and, purposely, forget the plot because I want to recreate the experience of my enjoying it.  When this is done, I’ll leave it behind until the print comes up and then I’ll re-watch the film in its entirety through that print.

[alexp120]

The DTS audio files of the Cinema DTS mix for both the Fox-distributed and the Paramount-distributed versions has been upload.

I’ll be taking PMs from volunteers to check-out my work.

Actually, the files have been uploaded since Jan. 3rd. I thought my last post was clear in that they would be ready to download by that said date, so, I apologize to all of you for my not making it clear.