Audio engineer Scott Hirsch breaks down the concept of mixing audio to appropriate levels. In this video tutorial using Adobe Audition, Scott explores a new type of loudness meter, used to mix to broadcast level specifications according to worldwide committees on program loudness, such as the ATSC and EBU. The Adobe Audition plug-in Loudness Radar is used to discuss key concepts like loudness units or LUFS and how they pertain to mix levels for internet and broadcast projects.
- [Voiceover] If you're like most media producers, you might've scratched your head about how loud or quiet to mix the audio for your project. The short answer is that there's not one absolute answer. Mix levels really depend on what your intended venue is. Let's discuss mix levels and how we can use some advanced modern metering that measures perceived loudness to explore some ideas on how to get our mix level right for our intended presentation venue. One thing to know about meters is that traditional meters, like the ones that show up here in Audition at the bottom, in Premiere, in Avid, Final Cut Pro, even ProTools, they don't tell you everything you need to know about volume.
Especially in terms of perceived loudness. Basically, these types of meters are good at showing peak levels, which tell us about the actual instantaneous reading of the audio level. But those readings aren't giving much info about how loud the material actually sounds to listeners. In other words, two different mixes might be hitting the same peak levels on this meter, but one will sound way louder than the other when it gets played on TV, the Web, or anywhere else. For years the broadcast industry has tried to standardize this, and they've made some great strides lately.
The key to all of this is a new breed of meters that are becoming standard to mix your audio in a way that measures loudness perception rather than just technical levels on the meter. It's possible to get a loudness perception meter with any digital audio workstation, and with Audition we have access to one meter just like this, as a track plugin. It's called Level Radar. Let me show you how it works. So, when we measure the overall loudness of our program, we wanna measure what's happening at the output of the master track, so I'm gonna select the master track by clicking on it, and go up to the Effects rack, and here, I wanna make sure Track Effects is selected, and I'll go in here and choose, under Special, that's where it lives, the Loudness Radar meter.
And here it opens this perceptual loudness meter. It looks a little different than some meters we're used to, and notice it's a partnership with TC Electronic and Adobe. TC Electronic is one of the leaders in the field of loudness measurement, so it's great to have them on board here. Now, there's some different presets you can set up in the Loudness Radar, and if I open this, we actually get a list of acronyms that might not be familiar to you. Basically, these are different standards, committees, loudness specifications, and the ATSC is the one we use in North America.
The EBU is the European Broadcast Union, and TR is the Japanese loudness standards committee. They're almost all identical, there's some slight nuances way beyond anything we need to worry about talking about in this course. Basically, you can just pick any one of these three if you're going for a broadcast level loudness, and since we're in North America, I'll choose the ATSC one. Now, there's two different flavors of ATSC loudness specs, and the difference here is that they use slight difference in the units measured.
Now, here's some new terms for us, and I'm gonna talk about this in a second. For now I'm just gonna choose the first one, ATSC A/85 LKFS. Now, LKFS, that is a term, the main part of that term we're concerned with is the L, and you saw it down here too, LU, the loudness unit, that's what LU stands for. And that's sort of a new concept in terms of perceptual loudness. The cool thing about the loudness unit is that it's roughly equivalent to a one decibel change on your track meter, so one loudness unit equals one decibel change in track volume on your master track or, for example, your dialogue bus.
So, that makes it very simple as we work through this, you'll see why that's super important. For now, LKFS, that stands for loudness K-weighted full scale. Again, it's just working with these loudness units, and this is just a difference of looking at K-weighted full scale or LU, which changes the meter to have a zero in the middle, as opposed to LKFS has a -24 in the middle. Nothing else is different, it's just where the numbers are on the meter.
And you can use either one of them, the main point is, if you're going for broadcast loudness, the sort of magic number is right here in the middle at, for LKFS, -24. If you're deciding to use loudness units, then it's at zero, so you can aim for either one, that should be your target. I'm gonna use LKFS for now, because that's what I'm most used to using, and I'm just familiar with that magic number being right at -24 LKFS. And what I mean by this, as a magic number, is that this is an average over your whole program, so when I hit play, we wanna play the whole piece and see where that averages out to, which will be shown in the bottom right down here.
And when we're done, we can make the appropriate adjustments to get it up or down to that level. You'll see what I mean once I start playing. The meter itself, as it's going around, it starts down here and it goes around in a circle, the meter itself is showing us instantaneous levels, so that shows us at any given snapshot where our meter is. Again, that's helpful for setting your levels as you're working, but in the end you're really concerned with what the magic number is down on the bottom right. So I'm gonna hit play, and let's see, as I've mixed this right now, just by working through and kind of getting the volumes where I need to be, we'll see where it lands on the LKFS meter.
Okay, so it's low, but we haven't heard any dialogue yet. Here comes the dialogue. Now, as you can see, some of the dialogue's above -24 on the instantaneous meter, some of the dialogue's below, but we're really looking for this average in the bottom right. (characters speaking) Okay, so as you can see, we're extremely close, this is in spec for the -24.
Again, if this read, let's say, -22, very simple. You can choose to raise your master level, or perhaps just your dialogue level or all three of your stems up that one or two decibels needed, and the meter will read that once you play it again, so that's the usefulness of using this loudness unit, is that you can accommodate any changes once you play the whole program and it reads maybe one decibel shy or one decibel over, you can just adjust your master levels to accommodate that and it will go into spec.
Now, speaking of specifications, we've been talking about broadcast level, this is appropriate for television, for cable, that sort of thing. What about the Internet? The Internet is sort of a Wild West in terms of levels, however, it's typically much louder than broadcast levels. There isn't a set of standards like a magic number on the Internet, but in general, the consensus is that about -16 is a better place to be competitive, and this is because people are listening on their laptops, on their iPhones, they've got music playing, which is always louder than program material, or video material, so we want to be competitive with that so that when your video plays it's not too quiet.
So we wanna aim more around -16 for a web delivery. So again, it's pretty simple, once we get this magic number, we can adjust our levels accordingly to match that -16, and I'll show you how we would go about doing this, so we wanna get about eight decibels louder to get to the -16 range, and to do this I can show the mixers view, so we haven't seen this yet in this course, but if you want to show the mixer and it's not showing up as a tab here, we can go to the Window pulldown menu and we can choose Mixer, and that shows us all of our tracks with track faders that we can adjust.
Now, over here on the right, we have our three stems, and I'm gonna adjust those the appropriate eight decibels louder to get us more in the range of the Internet loudness. Now, one thing you have to be aware of is that since we're boosting the levels quite a bit, we're now gonna be in danger of hitting the peak, hitting the top of the meters and possibly distorting, so one thing when you're trying to create a louder mix is you have to give on the top of the range with a limiter to make sure you don't go over by a certain amount, so when it hits the top it's sort of a brick wall limiter that'll keep the very peak levels in check, so I'm gonna go on to the track itself, you can do track effects here in the mixer window, so I'm gonna go in here, and I'm gonna choose Amplitude and Compression, Hard Limiter, and I'm gonna put a hard limiter in there, I'll choose a true peak hard limiter, and I will turn this down maybe to about one decibel so that it never gets above - 1 decibels, so it's right at the ceiling, okay? And I'm gonna put that, by holding CMD or CTRL for Windows, I can drag this to all three of the stems, and then I'm gonna do it one more time, I'm gonna actually move the loudness range down one slot, and also put a hard limiter in on the master.
So that way we're ensuring that we don't hit the peak on any of these meters. Now, once I've done that, I can go in here and I'm gonna raise this the eight decibels louder to get in that range of the Internet levels, and I'll do that to all my tracks, so we'll see how it works. I'm just trying to get it right there, okay, 8.1, that's fine. We'll see if it ends up being too loud, because remember, this is cumulative and we're blending all three of these, so by turning them all up there's a chance that we might go a little bit above -16, but maybe not, because dialogue is really the dominant thing happening.
Just raising this eight might get us right in the ballpark, and we've got our hard limiters in place, so let's go ahead and play the show again from the top and see where we land on the meters, now one thing I wanna do is reset the meter by clicking the reset button in the top right, here we go. You hear it's much louder in our headphones. We'll let it play out and see where it goes. (jaunty music) (characters talking) So I'm gonna stop it there, and as you can see, by raising everything the eight decibels, the loudness unit's measurement worked, and we're able to hit our target value of -16.
Now, if you had your headphone levels where I had mine, that's really loud, but that's where you really wanna be for Internet levels, you wanna be competitive with all that other loud content on the Internet. So, those are some rules of thumb in terms of getting a much more exact and industry specific way to meter the loudness of your program. And you can use this loudness radar in Audition, or, if you don't have Audition and you're using any other digital audio workstation, make sure you get one of these new breeds of loudness metering that measure perceptual volume using LUs, loudness units, or the LKFS scale, and you'll have a much easier time managing the levels of your project.
- Capturing audio and following the proper workflow for optimum results
- Sound editing—improving and restoring audio in post-production
- Mixing and exporting audio or preparing it for handoff to a professional audio engineer
The second and third steps feature Adobe Audition CC, a powerful audio post-production program with a host of tools to clean up, sculpt, and finesse your sound design. The seamless workflow to and from Adobe Premiere Pro makes it a powerful audio toolset. However, author Scott Hirsch's techniques work equally well in other video and sound editing applications. Watch this course to learn practical techniques for getting better sound in all your productions.
- Choosing the right gear, including lavalier and boom mics
- Syncing offline devices
- Working with audio in the video editor
- Moving files to Audition
- Choosing sources
- Cleaning up and getting the most out of nonideal audio
- Reducing noise
- Adding sound effects
- Mixing and adjusting levels
- Exporting and managing final files