Normalize to -23 LUFS or 0 LU?

[fwrunner2018]

Hi;
I apologize if this sounds stupid, but I'm just an amateur playing with Reaper for mixing.

What is special about 0 LU or -23 LUFS (which appear to be the same thing)?
Reason I ask is that normalizing to these values is available directly from the Properties > Volume menu, while normalizing to a user defined value needs to be run using SWS Extensions from the Actions menu.

That said, I did set a shortcut that will take me directly to the SWS action.

It seems to me that the streaming services like YouTube and Spottify use -13 to -16 LUFS, not -23 LUFS, so why the pre-set actions in Reaper?

Thanks
FW

[xpander]

Originally Posted by fwrunner2018

What is special about 0 LU or -23 LUFS (which appear to be the same thing)?

They are not quite the same. LUFS is an absolute scale, LU is for the relative scale. You could have for example set your metering reference level to -23 LUFS, that point would then be your 0 LU. So if you have a LU reading of -2.1, that means you are -2.1 dB below your LUFS reference level etc.
Analyze and normalize loudness with SWS
https://forum.cockos.com/showthread.php?t=150705

The -23 LUFS is what EBU (European Broadcasting Union) recommends as the average loudness.
https://tech.ebu.ch/docs/r/r128s1.pdf

Maybe it's the only LUFS preset in Reaper because it was one of the publicized "safe" recommendations back then and streaming services didn't have their normalization practises going on yet or had not publicized their standards.

[ashcat_lt]

I don't have anything like a Properties>Volume menu. The only Normalize actions native to Reaper simply set the peak level to 0dbFS.

Like xpander said, the -23LUFS thing is like the standard for broadcast in Europe. It's in those "loud commercial" laws that came down a while back. That action is, of course, normalizing based on integrated average "loudness". Its actually a reasonable place to start for individual tracks. Not far down from nominal -18, and reasonable compromise between sustained and percussive material.

[fwrunner2018]

OK. I get it now.
Someone should talk about LUFS and the standards with bands like Green Day <g>