Plain Ole Stereo - how to build?

[smorgasbord]

I just successfully built my first DCP, thanks to the manual and this forum.

The sound of my documentary is plain ole stereo: Stereo music and "panned" narration/interviews. That is I adjusted the left and right balance of each source voice track to be either in the center, a bit to the left, a lot way left, a bit to the right, and a lot way right. For my DCP, I simply specified 2 Channels and put Left on 1 and Right on 2.

Should I have done something different? I saw that there's an option or Mid/Side which I think pulls the common sounds on each channel into the center. Would that help or hurt? What do I do about the empty 4th channel? Is it OK then to specify 4 Channels or should I specify the full 6? I'm assuming that doing the up-conversion to 5.1 isn't ideal given my movie doesn't have special effects - better to just let the theater decide how to pipe the channels they're getting.

So, what would you recommend for my documentary? Should I just keep the stereo or something else?

And then, if something else, how to make those changes in the DCP-O-Matic project without needing to re-transcode the video portion?

[carl]

Hi there,

I am no cinema mastering engineer but my guess would be to leave it in stereo. The other reasonable alternative would be to use the mid-side decoder which does, as you say, pull common parts of L/R into C. This might sound better in a cinema, whose sounds systems are kind of set up to expect music in L/R and dialogue in C. There's no real way to be sure other than to listen to the difference.

Any empty channels will be filled with silence, so there is nothing to worry about there. According to the standard (as I understand it) you should be fine specifying 4 channels but 6 is more common so might be wise. It'll only make the DCP slightly bigger.

If you still have the DCP-o-matic project you can change the audio settings, re-make the DCP and it will re-use the video from the previous run so it should be fairly quick.

[Carsten]

Yup. You could try the Mid-Side decoder options, but make sure you saved your original DCP. And I can only recommend to actually use these decoders if you are allowed to check the result in a real cinema with proper 5.1 or 7.1 audio system.

We cinema people prefer at least an L/C/R mix, but it's still better to leave it in plain stereo if you can't quality check other versions in a cinema.

- Carsten

[smorgasbord]

You could try the Mid-Side decoder options, but make sure you saved your original DCP. And I can only recommend to actually use these decoders if you are allowed to check the result in a real cinema with proper 5.1 or 7.1 audio system.

OK, I'm back. My film has gotten into a few Festivals, but none until now have wanted a DCP. Well, one said they wanted DCP but they ended up using the backup Blu-Ray I sent them.

But, now we're screening in at the AMC Theater near the Boston Common in less than a week and a half - what should I do about my sound?
1. The Narration is equal on both channels
2. Talking heads on-screen are "panned" towards the left and right of center according to where they are located on screen, but no-one is all the way over to the left or right.
3. The background music is true stereo.
4. There is no live-action sound, nothing recorded with a stereo microphone.

I think my best option may be to leave it as L/R, but I'm concerned that this professional theater won't like not having a center. Should I use the mid-side decoder?

And unfortunately, I live on the other side of the country, so there's no way for me to test it out there. Maybe the Festival will run a check, but there's not really enough time: if the DCP doesn't pass they'll probably just play the Blu-Ray.

So, one final advice on using the mid-side decoder or not, please.

PS: My peak level is -1.17dB, so I set my Gain to -2.5 and now the peak is -3.67dB. Is that my best choice, and if not, what is?