I was on one of my facebook channels recently and there was a discussion about LUFS. LUFS? No this is not a German word meaning anything about wind or flying or airplanes or...nevermind. Its a term that sound engineers use to describe perceived sound loudness. Wait, don't we already measure that in terms of dB? Well, yes and no. A really loud firework can be greater than 140 decibels. The nice nurse that scared the complete fecal matter out of me the other night apparently knocked at a whopping 10 decibels (sound of breathing).
But I digress. We do measure the loudness of sound in many ways and we usually measure them in those decibels.
A little history on decibels: The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10^1/10.
Ok. Enough of that. We're here to talk about LUFS, right? Ok, so lets talk about that. LUFS, or LKFS which is "Loudness, K-Weighted, relative to Full Scale" is a standard loudness measurement unit used for audio normalization in broadcast television systems and other video and music streaming services according to Wikipedia. It describes the percieved loudness based on a special algorithm. Don't ask me to describe it, but there is a standard about this: ITU-R BS.1770. YOU go check that out.
So Woody, what does this have to do with the price of eggs? Well, the price of eggs have gone up substantially based on a number of factors. Mostly... Nevermind.
Ok, back to the topic. Streaming service have loudness standards that do not necessarily relate or are based on the -dB you set your mix to. Mix in my case is the final product such as all my voiceover and podcast episodes. I'm still learning how those levels relate or even how to get to those levels without having my sound clipped or distorted. Its a challenge, but I do want to share what I have found out so far.
All of my experimentation lately came from watching a Youtube video from Lenny B called How To Make Your Voice-Overs Louder With Mastering. I still haven't wrapped my head around the whole thing, but its interesting how the 'loudness' in the mastering process can mean the difference between a good demo, audition or final mastered product and a great one.
So if you want, stop right here, watch the video and come back. No worries. I'll wait.
Whew. 15 minutes, but it was worth it. When I watched it again, I found I missed something. Something very important. Something I was trying to figure out and couldn't quite get the sound.
Anyhow. So as you probably saw in the video, Lenny mentions that the use of a limiter and the threshold settings on your limiter, can do something that normalization simply cannot do. That is to bring up the overall loudness past what normalization does, then clips off the tops. Take a look back to the video and you'll see the wave form at about 0:55 and it looks like someone trimmed the grass.
Did you also catch that he says "Louder is Better"? Have you ever watched a Youtube video and noted it just wasn't loud and sounded thin? There you go.
Why is this important? Well, the underlying volume will increase as well, as in normalization, but the limiting will keep out any clipping. Assuming you set the ceiling or the limit, you'll be ok and your audio won't sound clipped. No one likes clipping, especially with earbuds or other in-ear devices.
Now, once you create your mix or voiceover, you want to check it with some sort of meter. I recommend the Youlean Loudness Meter 2 which has a handy VST plugin for most DAWs (Digital Audio Workstations). I placed mine as the last-of-the-mix plugin right at the bottom of the Master Track. You could place in on each track, but honestly why? Just do it at the end before the sound comes out of your hardware. Once you save/render/mix/whatever your final product, it should be right on target!
Ok Woody. Sounds great. What's the target?
Well I'm glad you asked! Youlean published a chart that has most all the online streaming sources and their specs. You can find it here. I publish on Anchor which is owned by Spotify, so I use the Spotify specs of -14 LUFS with a Max True Peak of -1dB. Youtube has the same specs in case you need to know.
So to conclude, I will confess I have learned a LOT about percieved loudness and how to make my voiceovers sound better. Try it. You might like it. For me, I'm still experimenting and I know I will be making it better. If you have any input, write it down below in the comments!
Cheers. -Woody