AVID TRAINING | FINISHING YOUR DOLBY ATMOS MIX 

As with everything you’ve learned about Dolby Atmos in the first three articles, finishing up your Dolby Atmos mix is a little different from what you’ve done before in stereo or traditional surround format sessions. Don’t worry though -” it’s easy (and powerful) if you know the tricks!

Trim and Downmix

When you’re mixing from one channel format to another (for example, from 5.1 to stereo), the downmixing process follows a set of rules. When we’re working in non-Dolby formats, there are a couple of ways that we can do this:

• By using the DownMixer plug-in (here you see an example of a 5.1 track being downmixed to stereo)

• Through the use of routing coefficients, which you can set in the bottom of the Mix tab of the Pro Tools Preferences dialog box.

Downmix coefficients in the Pro Tools Preferences dialogue box

While these two features are great tools for traditional downmixing, they don’t apply to Dolby Atmos formats. To take control of your Dolby Atmos downmixing, you’ll need to open the Trim and Downmix dialog box. Here’s are two ways:

From the Window menu, open the Dolby Atmos Renderer. In the Dolby Atmos Renderer window, click the Trim & Downmix button. The Trim and Downmix dialog box will appear (when the dialog box is shown the button will turn orange, as shown here).

• From the Setup menu, open the I/O Setup dialog box. From there, click the Dolby Atmos tab, and then click the Trim and Downmix button in the lower right-hand corner.

The Trim and Downmix dialog box enables you to customize how your mix will sound when you’re monitoring the mix or exporting re-renders (which we’ll talk about later in this article). Let’s take a look at the basic components of this window:

1. New Session Defaults/Current Session tabs: You have the ability to adjust the settings of the session you’re currently running (by clicking the Current Session tab) or the settings that will be used when a new session is created (by clicking the New Session Defaults tab)

Changes that are made in the New Session Defaults tab are saved to your system’s Pro Tools Preferences. Changes that are made in the Current Session tab will be saved as part of your session file

2. Trims and Balance: Here you can adjust gain and position of various elements when mixing down to different formats. The values in the "Trims" section allow you to adjust the levels of your surround and overhead channels. The values in the "Balance" section enable you to choose the position of overhead and surround channels in relation to the front or back of the listening space. For each format, the "Auto" box is checked by default, meaning that the different parameters will be unavailable to you. Removing the check mark by clicking this box will give you the ability to click on any parameter, which will display a list of options for you to choose from.
3. Downmix Control: In this section, you can choose your mix coefficients. There are default settings here as well, which you can change based on your specific mixing needs (the Pro Tools Reference guide goes into each of these different options in detail).
4. Tab Mismatches: While it’s not "wrong" to have different settings between the New Session Defaults tab and the Current Session tab, you definitely want to know when those differences arise. Pro Tools makes this easy in a number of different ways:

• Any fields with differences between the two tabs will be highlighted in orange.
• The button in the bottom right-hand corner of the Trim and Downmix dialog box (which will read "Apply New Sessions Defaults" when you’re viewing the Current Session tab, or "Apply Current Session" when you’re viewing the New Session Defaults tab) will turn orange, and clicking it will apply the settings from the currently hidden tab. This is a quick way to resolve any mismatches between the two tabs.
• The Trim & Downmix button in the Dolby Atmos Renderer window will turn orange (when the Trim and Downmix dialog box is closed)
• The Trim and Downmix button in the Dolby Atmos tab of the I/O Setup dialog box will turn orange.

Exporting an ADM File

When you bounce your mix for playback in a Dolby Atmos setting, you’ll need to preserve all of the bed and object data that you’ve created in your session. The file format that supports that kind of metadata is called an ADM BWF file. Long-time users will recognize the "BWF" as "Broadcast Wave Format", and the ADM acronym stands for "Audio Definition Model". Bouncing to this format will enable a Dolby Atmos-compatible playback device to decode the bed and object data according to the needs of the playback environment.

The first steps in bouncing to an ADM BWF file are the same as normal bouncing -” select the area in the timeline that you want to bounce, and then go to File > Bounce Mix. In the top of the Bounce Mix dialog box, name your file descriptively as you would normally do.

The first difference in your workflow: From the File Type menu, choose Wave (Dolby Atmos)

When you choose Wave (Dolby Atmos) as your file type, a new section -” called Dolby Atmos -” will appear:

1. Create Master File (WAV ADM BWF): You have the ability in this section to create a new ADM BWF file, or a WAV Re-Render (which we’ll talk about later) or both. Since in this case we want to create a Dolby Atmos Master File, check this box.
2. Beds and Objects: This section will display the number of used Beds and Objects in your session. If these values look incorrect, you can click the I/O Setup button to the right of these fields, which will open the I/O Setup dialog box and enable you to make any adjustments that might be required. After making changes in the I/O Setup dialog box and clicking the OK button, the values shown in this section will update accordingly (you will not need to close the Bounce Mix dialog box to make these changes).
3. Add FFOA: FFOA stands for First Frame of Action, and is an optional bit of metadata that can be added to the ADM BWF file, if your delivery specifications require it. Entering a value outside of your selected timeline area is not allowed.
4. Frame Rate: The frame rate that is displayed here is based on the frame rate that you’ve chosen in the Session Setup window. It’s not changeable here, so if you’re seeing the wrong frame rate, you’ll have to close the Bounce Mix dialog box, then change the frame rate in the Session Setup window, and then open up the Bounce Mix dialog box again.
5. Apply program-level metadata from: Program level metadata (which includes downmix coefficients, trim, and balance settings) can be drawn from different sources based on different workflows. For the purposes of this tutorial series (using Pro Tools’ internal renderer), the field will read "Current Renderer Settings", and cannot be changed.

From this point on, the workflow is just about the same as when bouncing any other kind of mix, though it is worth noting that when you choose Wave (Dolby Atmos) as your file type, the only two available sample rates are 48 kHz and 96 kHz.

Bouncing Re-Renders

In addition to (or instead of) creating an ADM BWF file, you have the ability to bounce re-render WAV files in a variety of formats. For example, let’s say that you are bouncing an ADM BWF file, but you also want to create a binaural WAV mix to listen to on headphones -” you can easily create both mixes at the same time.

The process of bouncing a re-render starts the same way as when you create an ADM BWF file -” select the area on your timeline, open the Bounce Mix dialog box, and choose Wave (Dolby Atmos) as your file type. Here’s what you do next:

1. Click the Create Re-Renders (WAV) check box. As soon as this box is checked, you’ll see additional parameters appear, as shown here.
2. Next, you’ll want to set up the various re-renders that you want to create. To do that, click the Configure button. The Re-Renders dialog box will appear.
3. Type a name in the New Re-Render field, and then click the Plus button.

4. Click the disclosure triangle in the Format Column, and a list of available formats will appear. Choose the desired format for the re-render (the currently active format is indicated with a check mark).

5. You can create multiple re-renders using these steps: In this example, we’re have the ability to bounce three re-renders -” a binaural mix, a full 5.1 mix, and a 5.1 M+E (Music and Effects) mix. By default, these re-renders will bounce the entire mix (meaning all of the beds and objects in your session. That works well for our binaural and full 5.1 mix.

6. You also have the option to exclude elements from your re-render. For example, in a typical M+E mix, we want to bounce only music and effects. Clicking the Custom radio button will enable you to include or exclude the following:

• All Beds
• All Objects
• Any individual group assignments (made in the Dolby Atmos page of the I/O Setup dialog box)

In the example shown here, only the beds and objects that are assigned to the "Music" and "Effects" groups will be included in the "5.1 M+E Mix".

Dolby Atmos Groups

The list of available groups you see in the Re-Renders dialog box are specific to Dolby Atmos mixing, and shouldn’t be confused with your normal Mix or Edit groups. Though the
management of Dolby groups is a bit beyond the scope of this article, if you want to experiment, here’s how to start: In the Dolby Atmos tab of the I/O Setup dialog box, click the disclosure triangle in the Group column of any bed or object. A menu will appear (as shown here), from which you can associate that bed or object with a single group.

Live Re-Renders

To the left of each re-render, you’ll see a Live check box. Though this doesn’t relate to bouncing your re-renders, it’s worth knowing about: Any re-render that is set up as a "Live" re-render will, in addition to being accessible from the Bounce Mix dialog box, be available as a re-render input within Pro Tools.

For example, here we have two re-renders that are enabled as live re-renders (this works for both Full Mix and Custom Mix re-renders):

You’ll see here that they are available (on the appropriate tracks) as inputs from the re-renders submenu of the track’s Input selector.

Once you’ve set up your custom re-renders, you’re ready to bounce them:

7. In the File Format menu, you can choose whether to create a single interleaved file (per re-render) or multiple mono files.
8. Clicking the Re-Renders menu will reveal a list of all of the re-renders that you created in the Re-Renders dialog box. Simply choose the one you want from the list.
9. You can bounce multiple re-renders at once: Simply click the plus (+) button to add another row in the Re-Renders section. Clicking on the new row’s menu button will reveal a list of available re-renders. Clicking the minus (-) button will remove a given row.

It bears mentioning at this point that you don’t have to bounce all of the re-renders that you created in the Re-Renders dialog box!

10. You have the option of importing your re-renders back into your session by clicking the Import Re-Renders After Bounce check box.

From this point forward, bouncing re-renders is the same as any other format -” choose a sample rate, then a bounce destination, and click the Bounce button in the lower right-hand corner, and you’re done!

Two Bouncing Rules

Before we leave our discussion of bouncing ADM files and re-renders, a couple rules to bear in mind:

• In the second article in this series, we used stock re-renders to give us an easy way to use loudness metering and binaural monitoring within your session. These stock re-renders are not accessible from the Bounce Mix window.
• Also in the second article, we learned how to set up a Master Fader as a volume control for the Dolby Renderer. Any processing that you place on this Master Fader track will not be included in any ADM BWF or re-render bounces. This Master Fader is only intended to be used for monitoring.

A First Step Into A Larger World

It’s not an overstatement to say that the Dolby Atmos format has had a seismic impact upon the audio industry. In a few short years it has evolved from an innovative idea on the fringes to established workflows across the audio production spectrum. The verdict is in -” Dolby Atmos is here, and it’s here to stay.

In this series of articles, we’ve endeavored to demystify the concepts and mechanics behind Dolby Atmos. If you’ve followed the steps in these four articles, you now know how to create a basic Dolby Atmos mix using Pro Tools’ internal Dolby Renderer, and how to export it in a few different ways.

That being said, mixing in general is a deep topic, and that’s especially true when mixing in an immersive, object-based format like Dolby Atmos. These four articles should be seen as an introduction into this new way of working only -” there’s a lot more out there to learn. As you engage with other professionals, you’ll find that there are multitudes of perspectives and approaches when mixing in Dolby Atmos, but they all rely on the key concepts you’ve learned here.

Dolby, in cooperation with Avid Technology, have created a series of in-depth certification courses that cover everything from the basics to advanced techniques when working in Dolby Atmos. Promedia Training, with Avid Certified Instructors on staff, offer these courses and certifications. You can learn more about them HERE.

We hope that you’ve learned from these articles, and we can’t wait to hear what you create!

Part 1: Click Here
Part 2: Click Here
Part 3: Click Here

Author: Andy Hagerman

Avid Master Pro Tools Instructor

Andrew Hagerman has been a professional musician and teacher for the majority of his nearly 60 years. Beginning his musical life at the early age of eight as a tubist and bassist, Andy continued his studies at the prestigious Northwestern University in Chicago, Illinois. During his time there, MIDI and computer music were in their infancy, and Andy recognized the usefulness of these new technologies in aiding the creative process. He had the unique opportunity to learn these tools as they were being created and refined, and his quest for the best in audio and music technology ultimately led him to use and teach Avid’s Pro Tools.

Andy has accumulated varied experience as a performer, composer, arranger, and producer, including as a musician and arranger for Walt Disney productions and Tokyo Disneyland, to composer, arranger, and producer on a wide range of music projects and post-production work. As an educator, he began teaching at Full Sail University in Winter Park, Florida, where he rose to the position of Associate Course Director of Advanced Audio Workstation Studies. in 2005, he joined the training team at Avid Technology as Training Services Manager for the Asia-Pacific region (with his office based in Tokyo Japan, where he resides today) and then moved to the role of curriculum manager within the learning services team. During this period, he authored the industry leading Pro Tools 101 and Pro Tools 110 certification courses.