thread: Downmixers....
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Old 28th July 2020 | Show parent
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What I bolded is wrong. That's the first thing I noticed.
When sending a discrete center into Spanner 5.1/2 plugin, it respects the equal panning law which means, L and R are already getting a -3dB center signal each. If you are additionally pulling down the center -3dB, then you have obviously overcompensated.

You can check it with a signal generator. This is also true for Pro Tools (well modern versions): a mono bussed to a stereo will be -3dB on each left and right. Not full signal on both left and right.

Originally Posted by postprosound ➡️
I hear ya! That’s what I thought too! Try it for yourself. I took a 5.1 print master ran it through spanner. L & R at unity. Center down 3. Ls and Rs down 3. Just like you should. Resulting stereo consistently 2-3 dB lower when I compared it to the 5.1 trough VisLm. I mean, please, tell me where I messed up. I’d prefer to be wrong in this case! If I have a chance post post a screenshot tomorrow.
You also haven't mentioned what you are doing with the LFE. In addition, there's always the chance of phase issues on fold down which will change the summed signal levels due to channel content or mixing decisions. Most of these should not be significant enough to throw integrated loudness but depending on duration and content, it has the possiblity.

I'll leave you a link to Netflix's fold down instructions as a guide

I'll have to investigate how surround content is weighted for the ITU integrated loudness standards.