Confused - LUFS and RMS - Arrgh!

[KenTheriot]

I have mastered many albums in Audition. One thing I always do is check average loudness by using the Window/Amplitude Statistics and look at Average RMS Amplitude. I try to get all my songs in the same range of around -14 dB. That has served me well.

But now 'm hearing and reading that it's all about LUFS now and NOT about RMS. I understand what LUFS stands for wand that it means in theory. But I still sometimes see people using RMS and LUFS almost interchangably. 

Also, I notice that in Audition's Amplitude Statistics, there is no LUFS to be seen. 

I'm happy to keep using the Audition RMS stats, but with the emphasis lately on streaming services using target LUFS levels, how do I find out what the LUFS of a song is using Audition? 

Please help me und 

[SteveG_AudioMasters_ · Accepted solution]

No LUFS to be seen...?

[KenTheriot]

Doh! OK, no LUFS to be seen by me :-P. Thanks for that!

So I went back to that same song and saw that it said ITU-R BS.1770-3 Loudness: -14.39 LUFS

I'm still trying to fully grok the whole LUFS thing. When it says that my loudness is -14.39 LUFS, does that correspond to dB in any way? Since "LUFS" seems to be used as the unit of measure, it would seem not. But I've seen others say things like "the LUFS for this song is -14 dB." Would that be incorrect?

Thanks again!

[SteveG_AudioMasters_]

I suppose that the easiest way to explain it is to say that yes, LU's (Loudness Units) are dBs. So if you increase your overall level by 1dB you'll end up with a 1 LU lower number*. Where they get more complicated is that this number is derived in a relatively complicated way, but it's supposed to correlate more with the way that people perceive loudness - which isn't the same as how loud something actually is. Because they are valueless (like dB) you have to reference them to something, and that's where the FS bit comes in - Full Scale. So you have these units that are quite hard to calculate, don't have any immediate apparent relationship with your program, but you are still supposed to use them as a reference!

If you want to know more about this (and let's face it, who doesn't? 😉 ) then you need to look into the background behind it - it's all predicated on something that acousticians have been doing for rather longer than the broadcast industry, and that is to make sound measurements and present them as Leq values. These take account of the amount of time that sounds occupy different levels, and yes, they have to be measured over a time period - in just the same way that LUFS are.

The trouble is, it isn't perfect. It's quite possible to make a program that conforms to a standard LUFS value and still have people leaping for the volume control - which pretty much defeats the object of it. Quite frankly, common sense and a little bit of understanding of your audience works better. In an attempt to get around this, the EBU has introduced the concept of Loudness Range, but hey, they haven't made it compulsory... (just a recommendation)

The BBC has an interesting document about it here. 

*You end up with a lower number because we are counting down from Full Scale - ie, 0dB.

[KenTheriot]

Thanks so much Steve!