Ensure Correct Volume for Playback

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Posts: 23
Joined: Mon Sep 02, 2019 2:16 pm
Location: United States

Ensure Correct Volume for Playback

Post by jakesinn »

Hello all,

I am an advertising manager for a local cinema. I use DOM to convert all the ads to DCP. We play all our content at volume 5.2 (ads, features, trailers) - Everything. Sometimes there will be an ad that plays back WAY too loud. How do I ensure that the content will playback at 5.2 with the same level volume as everything else?

In case this matters.... setup is:

Projector: Christie Solaria One+
Cinema Sound Processor: USL Model JSD-60
- Jake S.

Posts: 1564
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Ensure Correct Volume for Playback

Post by Carsten »

After gaining some experience, you should be able to use the LUFS value of the full audio analysis with reasonable confidence.

I suggest you load some of your preshow clips into DCP-o-matic and analyse them. Compare the LUFS values - I am pretty sure that these outliers will show up with a considerable deviation of their LUFS value. Please report back your findings.

This is an easy process - create a new project 'LoudnessCheck'. Add a typical sequence of preshow DCPs to it. Make sure you have checked 'Find integrated loudness...' in General prefs, as this will perform a full audio analysis immediately when adding content. Select each CPL/DCP individually, and choose 'Show Graph of audio levels' under the 'Audio' Tab. Check the number behind 'Integrated loudness' (LUFS).
For our preshow content and typical CP setting, -17 to -20 is a typical 'good' number. -20 to -30 LUFS is softer, it get's very loud towards -15 LUFS.
This can't be ultimately precise, but, it will at least prevent gross loudness variations.

You may need to find your own suitable LUFS value, though, it depends a bit on processor, sound system, room size, personal preference, etc.

Now, if you feel reasonably sure about this, you may create a new project, load a DCP into it that is too soft or too loud, and adjust it's level accordingly (gain setting).

E.G. if you find that your screen's best LUFS value is -19 LUFS, and that particular DCP gives a LUFS value of -24 - increase the gain by 5dB. If the clip comes out too loud at e.g. -15 LUFS - decrease gain by -4dB. The creation of the new DCP goes pretty quick, as only the audio is computed, while the image file is copied. Make sure the DCP settings are identical to the source - for most preshow content, it is probably flat/2k/5.1

Of course, you could also leave these DCPs untouched and insert suitable volume cues into your playlist. I can supply a table that matches dB values to JSD60 fader settings, so you can use suitable values to achive specific dB changes.

The attached screenshot is from a suspense movie trailer that I checked 'okay' for our typical preshow settings.

- Carsten

Bildschirmfoto 2020-02-11 um 23.23.35.png
Bildschirmfoto 2020-02-11 um 23.23.35.png (145.59 KiB) Viewed 255 times

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