OWC 12.4

Review: Nugen Audio’s VisLM2 loudness meter plugin

By Ron DiCesare

In 2010, President Obama signed the CALM Act (Commercial Advertisement Loudness Mitigation) regulating the audio levels of TV commercials. At that time, I had many “laypeople” complain to me how commercials were often so much louder than the TV programs. Over the past 10 years, I have seen the rise of audio meter plugins to meet the requirements of the CALM Act, resulting in reducing this complaint dramatically.

A lot has changed since the 2010 FCC mandate of -24LKFS +/-2db. LKFS was the scale name at the time, but we will get into this more later. Today, we have countless viewing options such as cable networks, a large variety of streaming services, the internet and movie theaters utilizing 7.1 or Dolby Atmos. Add to that, new metering standards such as True Peak and you have the likelihood of confusing and possibly even conflicting audio standards.

Nugen Audio has updated its VisLM for addressing today’s complex world of audio levels and audio metering. The VisLM2 is a Mac and Windows plugin compatible with Avid Pro Tools and any DAW that uses RTAS, AU, AAX, VST and VST3. It can also be installed as a standalone application for Windows and OSX. By using its many presets, Loudness History Mode and countless parameters to view and customize, the VisLM2 can help an audio mixer monitor a mix to see when their programs are in and out of audio level spec using a variety of features.

VisLM2

The Basics
The first thing I needed to see was how it handled the 2010 audio standard of -24LKFS, now known as LUFS. LKFS (Loudness K-weighted relative to Full Scale) was the term used in the United States. LUFS (Loudness Units relative to Full Scale) was the term used in Europe. The difference is in name only, and the audio level measurement is identical. Now all audio metering plugins use LUFS, including the VisLM2.

I work mostly on TV commercials, so it was pretty easy for me to fire up the VisLM2 and get my LUFS reading right away. Accessing the US audio standard dictated by the CALM Act is simple if you know the preset name for it: ITU-R B.S. 1770-4. I know, not a name that rolls off the tongue, but it is the current spec. The VisLM2 has four presets of ITU-R B.S. 1770 — revision 01, 02, 03 and the current revision 04. Accessing the presets is easy, once you realize that they are not in the preset section of the plugin as one might think. Presets are located in the options section of the meter.

While this was my first time using anything from Nugen Audio, I was immediately able to run my 30-second TV commercial and get my LUFS reading. The preset gave me a few important default readings to view while mixing. There are three numeric displays that show Short-Term, Loudness Range and Integrated, which is how the average loudness is determined for most audio level specs. There are two meters that show Momentary and Short-Term levels, which are helpful when trying to pinpoint any section that could be putting your mix out of audio spec. The difference is that Momentary is used for short bursts, such as an impact or gun shot, while Short-Term is used for the last three-second “window” of your mix. Knowing the difference between the two readings is important. Whether you work on short- or long-format mixes, knowing how to interpret both Momentary and Short-Term readings is very helpful in determining where trouble spots might be.

Have We Outgrown LUFS?
Most, if not all, deliverables now specify a True Peak reading. True Peak has slowly but firmly crept its way into audio spec and it can be confusing. For US TV broadcast, True Peak spec can range as high as -2dBTP and as low as -6dBTP, but I have seen it spec out even lower at -8dBTP for some of my clients. That means a TV network can reject or “bounce back” any TV programming or commercial that exceeds its LUFS spec, its True Peak spec or both.

VisLM2

In most cases, LUFS and True Peak readings work well together. I find that -24LUFS Integrated gives a mixer plenty of headroom for staying below the True Peak maximum. However, a few factors can work against you. The higher the LUFS Integrated spec (say, for an internet project) and/or the lower the True Peak spec (say, for a major TV network), the more difficult you might find it to manage both readings. For anyone like me — who often has a client watching over my shoulder telling me to make the booms and impacts louder — you always want to make sure you are not going to have a problem keeping your mix within spec for both measurements. This is where the VisLM2 can help you work within both True Peak and LUFS standards simultaneously.

To do that using the VisLM2, let’s first understand the difference between True Peak and LUFS. Integrated LUFS is an average reading over the duration of the program material. Whether the program material is 15 seconds or two hours long, hitting -24LUFS Integrated, for example, is always the average reading over time. That means a 10-second loud segment in a two-hour program could be much louder than a 10-second loud segment in a 15-second commercial. That same loud 10 seconds can practically be averaged out of existence during a two-hour period with LUFS Integrated. Flawed logic? Possibly. Is that why TV networks are requiring True Peak? Well, maybe yes, maybe no.

True Peak is forever. Once the highest True Peak is detected, it will remain as the final True Peak reading for the entire length of the program material. That means the loud segment at the last five minutes of a two-hour program will dictate the True Peak reading of the entire mix. Let’s say you have a two-hour show with dialogue only. In the final minute of the show, a single loud gunshot is heard. That one-second gunshot will determine the other one hour, 59 minutes, and 59 seconds of the program’s True Peak audio level. Flawed logic? I can see it could be. Spotify’s recommended levels are -14LUFS and -2dBTP. That gives you a much smaller range for dynamics compared to others such as network TV.

VisLM2

Here’s where the VisLM2 really excels. For those new to Nugen Audio, the clear stand out for me is the detailed and large history graph display known as Loudness History Mode. It is a realtime updating and moving display of the mix levels. What it shows is up to you. There are multiple tabs to choose from, such as Integrated, True Peak, Short-Term, Momentary, Variance, Flags and Alerts, to name a few. Selecting any of these tabs will result in showing, or not showing, the corresponding line along the timeline of the history graph as the audio plays.

When any of the VisLM2’s presets are selected, there are a whole host of parameters that come along with it. All are customizable, but I like to start with the defaults. My thinking is that the default values were chosen for a reason, and I always want to know what that reason is before I start customizing anything.

For example, the target for the preset of ITU-R B.S. 1770-4 is -24LUFS Integrated and -2dBTP. By default, both will show on the history graph. The history graph will also show default over and under audio levels based on the alerts you have selected in the form of min and max LUFS. But, much to my surprise, the default alert max was not what I expected. It wasn’t -24LUFS, which seemed to be the logical choice to me. It was 4dB higher at -20LUFS, which is 2dB above the +/-2dB tolerance. That’s because these min and max alert values are not for Integrated or average loudness as I had originally thought. These values are for Short-Term loudness. The history graph lines with its corresponding min and max alerts are a visual cue to let the mixer know if he or she is in the right ballpark. Now this is not a hard and fast rule. Simply put, if your short-term value stays somewhere between -20 and -28LUFS throughout most of an entire project, then you have a good chance of meeting your target of -24LUFS for the overall integrated measurement. That is why the value range is often set up as a “green” zone on the loudness display.

VisLM2

The folks at Nugen point out that it isn’t practically possible to set up an alert or “red zone” for integrated loudness because this value is measured over the entire program. For that, you have to simply view the main reading of your Integrated loudness. Even so, I will know if I am getting there or not by viewing my history graph while working. Compare that to the impractical approach of running the entire mix before having any idea of where you are going to net out. The VisLM2 max and min alerts help keep you working within audio spec right from the start.

Another nice feature about the large history graph window is the Macro tab. Selecting the Macro feature will give you the ability to move back and forth anywhere along the duration of your mix displayed in the Loudness History Mode. That way you can check for problem spots long after they have happened. Easily accessing any part of the audio level display within the history graph is essential. Say you have a trouble spot somewhere within a 30-minute program; select the Macro feature and scroll through the history graph to spot any overages. If an overage turns out to be at, say, eight minutes in, then cue up your DAW to that same eight-minute mark to address changes in your mix.

Another helpful feature designed for this same purpose is the use of flags. Flags can be added anywhere in your history graph while the audio is running. Again, this can be helpful for spotting, or flagging, any problem spots. For example, you can flag a loud action scene in an otherwise quiet dialogue-driven program that you know will be tricky to balance properly. Once flagged, you will have the ability to quickly cue up your history graph to work with that section. Both the Macro and Flag functions are aided by tape-machine-like controls for cueing up the Loudness History Mode display to any problem spots you might want to view.

Presets, Presets, Presets
The VisLM2 comes with 34 presets for selecting what loudness spec you are working with. Here is where I need to rely on the knowledge of Nugen Audio to get me going in the right direction. I do not know all of the specs for all of the networks, formats and countries. I would venture a guess that very few audio mixers do either. So I was not surprised when I saw many presets that I was not familiar with. Common presets in addition to ITU-R B.S. 1770 are six versions of EBU R128 for European broadcast and two Netflix presets (stereo and 5.1), which we will dive into later on. The manual does its best to describe some of the presets, but it falls short. The descriptions lack any kind of real-world language, only techno-garble. I have no idea what AGCOM 219/9/CSP LU is and, after reading the manual, I still don’t! I hope a better source of what’s what regarding each preset will become available sometime soon.

MasterCheck

But why no preset for Internet audio level spec? Could mixing for AGCOM 219/9/CSP LU be even more popular than mixing for the Internet? Unlikel. So let’s follow Nugen’s logic here. I have always been in the -18LUFS range for Internet only mixes. However, ask 10 different mixers and you will likely get 10 different answers. That is why there is not an Internet preset included with the VisLM2 as I had hoped. Even so, Nugen offers its MasterCheck plugin for other platforms such as Spotify and YouTube. MasterCheck is something I have been hoping for, and it would be the perfect companion to the VisLM2.

The folks at Nugen have pointed out a very important difference between broadcast TV and many Internet platforms: Most of the streaming services (YouTube, Spotify, Tidal, Apple Music, etc.) will perform their own loudness normalization after the audio is submitted. They do not expect audio engineers to mix to their standards. In contrast, Netflix and most TV networks will expect mixers to submit audio that already meets their loudness standards. VisLM2 is aimed more toward engineers who are mixing for platforms in the second category.

Streaming Services… the Wild West?
Streaming services are the new frontier, at least to me. I would call it the Wild West by comparison to broadcast TV. With so many streaming services popping up, particularly “off-brand” services, I would ask if we have gone back in time to the loudness wars of the late 2000s. Many streaming services do have an audio level spec, but I don’t know of any consensus between them like with network TV.

That aside, one of the most popular streaming services is Netflix. So let’s look at the VisLM2’s Netflix preset in detail. Netflix is slightly different from broadcast TV because its spec is based on dialogue. In addition to -2dTP, Netflix has an LUFS spec of -27 +/- 2dB Integrated Dialogue. That means the dialogue level is averaged out over time, rather than using all program material like music and sound effects. Remember my gunshot example? Netflix’s spec is more forgiving of that mixing scenario. This can lead to more dynamic or more cinematic mixes, which I can see as a nice advantage when mixing.

Netflix currently supports Dolby Atmos on selected titles, but word on the street is that Netflix deliverables will be requiring Atmos for all titles. I have not confirmed this, but I can only hope it will be backward-compatible for non-Atmos mixes. I was lucky enough to speak directly with Tomlinson Holman of THX fame (Tomlinson Holman eXperiment) about his 10.2 format that included height long before Atmos was available. In the case of 10.2, Holman said it was possible to deliver a single mono channel audio mix in 10.2 by simply leaving all other channels empty. I can only hope this is the same for Netflix’s Atmos deliverables so you can simply add or subtract the amount of channels needed when you are outputting your final mix. Regardless, we can surely look to Nugen Audio to keep us updated with its Netflix preset in the VisLM2 should this become a reality.

True Peak within VisLM2

VisLM Updates
For anyone familiar with the original version of the VisLM, there are three updates that are worth looking at. First is the ability to resize and select what shows in the display. That helps with keeping the window active on your screen as you are working. It can be a small window so it doesn’t interfere with your other operations. Or you can choose to show only one value, such as Integrated, to keep things really small. On the flip side, you can expand the display to fill the screen when you really need to get the microscope out. This is very helpful with the history graph for spotting any trouble spots. The detail displayed in the Loudness History Mode is by far the most helpful thing I have experienced using the VisLM2.

Next is the ability to display both LUFS and True Peak meters simultaneously. Before, it was one or the other and now it is both. Simply select the + icon between the two meters. With the importance of True Peak, having that value visible at all times is extremely valuable.

Third is the ability to “punch in,” as I call it, to update your Integrated reading while you are working. Let’s say you have your overall Integrated reading, and you see one section that is making you go over. You can adjust your levels on your DAW as you normally would and then simply “punch in” that one section to calculate the new Integrated reading. Imagine how much time you save by not having to run a one-hour show every time you want to update your Integrated reading. In fact, this “punch in” feature is actually the VisLM2 constantly updating itself. This is just another example of how the VisLM2 helps keep you working within audio spec right from the start.

Multi-Channel Audio Mixing
The one area I can’t test the VisLM2 on is multi-channel audio, such as 5.1 and Dolby Atmos. I work mostly on TV commercials, Internet programming, jazz records and the occasional indie film. So my world is all good old-fashioned stereo. Even so, the VisLM2 can measure 5.1, 7.1, and 7.1.2, which is the channel count for Dolby Atmos bed tracks. For anyone who works in multi-channel audio, the VisLM2 will measure and display audio levels just as I have described it working in stereo.

Summing Up
With the changing landscape of TV networks, streaming services and music-only platforms, the resulting deliverables have opened up the flood gates of audio specs like never before. Long gone are the days of -24LUFS being the one and only number you need to know.

To help manage today’s complicated and varied amount of deliverables along with the audio spec to go with it, Nugen Audio’s VisLM2 absolutely delivers.


Ron DiCesare is a NYC-based freelance audio mixer and sound designer. His work can be heard on national TV campaigns, Vice and the Viceland TV network. He is also featured in the doc “Sing You A Brand New Song” talking about the making of Coleman Mellett’s record album, “Life Goes On.”


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