Upmixing to 5.1 in Resolve with Penteo or DTS neural UpMix

Why it is important to have an LCR or 5.1 mix for cinema

In a stereo mix the dialogue are in the left and right channels and the audience will hear the dialogue from the speaker closest to them, depending on where they sit. In a 5.1 mix the dialogue comes from the center of the screen regardless of where in the auditorium the audience sit. To avoid some of the audience to hear dialogue from the left and some hear it from the right, stereo films should be upmixed to 5.1 or LCR.

Some cinema sound processors have upmixing options when playing a stereo DCP, such as ProLogic, which can convert stereo to 5.1. But it is not standard and when upmixing yourself you can decide to use either LCR or 5.1 upmixing. An LCR upmix is a safer option than a 5.1 upmix, because it uses only three channels (left, center, and right) and avoids potential issues with the surround and subwoofer channels.

Using DTS neural upmix and Penteo 16 pro plugins in Resolve

You can upmix stereo to 5.1 using the Fairlight DAW in Blackmagic Davinci Resolve and a 5.1 upmixing plugin.

I have tested the Penteo 16 pro ($499) and Waves DTS neural UpMix ($249) stereo to 5.1 plugins.

Both plugins can:

• upmix stereo to 5.1 and 7.1.
• downmix to stereo from 5.1 and 7.1.
• upmix from 5.1 to 7.1
• downmix from 7.1 to 5.1

DTS neural upmix

• Analyzes phase and intensity to make a 5,1 mix. Can be overridden by the depth and width sliders.
• Is not officially supported in Resolve, but worked when I tested it.

Penteo 16 pro

• Is officially supported in Resolve by Penteo
• Uses a phaseless upmix.

Note:
For more info on upmixing read this post on how to upmix in Pro Tools.

Upmixing from stereo to 5.1 in Resolve

Add a stereo video or audio file to the timeline.

In the Edit module, add a stereo track to the timeline.

Choose 5.1 Bus Format

Go to Meny – Fairlight – Bus Format.

Choose Format = 5.1 and click on OK.

Add an upmixing plugin to the 5.1 bus in the Fairlight module

Go to the Fairlight module

Click on Effects and drag DTS neural Upmix Stereo/5.1 or Penteo to “Bus 1”.

Configure the plugin settings and test it.

DTS neural upmix

I use a standard 5.1 upmix with lower LFE that I found to work for most content in the calibrated auditorium I use.

I lower the LFE by -7 and test the 5.1 upmix with “play”.

In the plugin, you can see the upmixed result

In the inspector (top right corner) you can also change the settings and remove the plugin with trashbin.

Note:
If the sound is clipping or too low, you can adjust the level with “Normalize audio level.”
Right-click the audio and use “Normalize Audio level”
Normalization Mode True peak
to a setting that does not clip like -8.
In DTS neural upmix you can also enable the limiter to avoid clipping.

You can adjust the loudness level for feature, trailer, or commercial levels. Read more about normalizing audio in this post.
If you want to run a limiter on the bus after the upmix plugin , you can add the built-in limiter to the bus after the upmixing plugin.

Note:
If you want an LCR upmix you could turn off the bass management and drag the depth slider to the front.

Penteo 16 Pro

After dragging the plugin to the bus, I click on the settings icon and change input and output order to L, R, C, LFE, lss, Rss, Lsr, Rsr,. This way, you will get audio files in the correct order like this:

1=L
2=R
3=C
4=LFE
5=LS
6=RS

In Penteo I choose discrete (hard center) and lower LFE by -7 (The default setting in Penteo is music, it has a wider sound with more phantom center sound.) The discrete 5.1 sound is similar to the default DTS neural upmix settings. This setting keeps dialogue in the center channel. The upmixing algorithm in Penteo is different so they do not match completely.

Exporting the 5.1 audio files

Go to deliver module.

When exporting sound files

Video options

Untick Export Video, if you are exporting only sound

Audio settings.

Export Audio is ticked. Export 32-bit float

Format: Wave
Codec: IEEE Float
Sample rate: 48000
Bit Depth= 32

Tick “Render one track per channel.”
Tick “Render as discrete audio Track.”

Output Track 1 = Bus 1 (5.1)

Click on “Add to render queue and “Render all”

The audio files will have this order
1=L
2=R
3=C
4=LFE
5=LS
6=RS

Optionally you can change the names from Test_A01.wav to Test.L.wav and so on.

To use these mono files in Resolve in a 5.1 DCP you can add them as mono tracks