In this series of free video tutorials, brought to you with the support of Avid, Post-Production Specialist and Immersive Audio expert, Alan Sallabank shares tips and tricks to help you get to grips with the audio post-production workflows for content to be delivered in Dolby Atmos Home Entertainment, which will be especially useful if you are delivering to the likes of Netflix and Amazon.

In part 4, we are taking a look at managing loudness in your Dolby Atmos Home Entertainment mixes to ensure that your mixes sound right whatever they’re played on.

What You Will Need

The Dolby Atmos Production Suite and The Dolby Audio Bridge are software solutions, so while you don’t need any specific Avid or Dolby hardware to follow the advice in these tutorials, you will need specific versions of software -

• Pro Tools Ultimate 2019.10 or later - 2020.3 recommended

• Dolby Atmos Production Suite v3.4

Running everything in software does also put quite a strain on your host computer, so I would also recommend that you are running a machine with at least six physical cores and at least 32GB of RAM.

Consider Watching Parts 1, 2 and 3 Before You Go On

If you are new to Dolby Atmos we strongly recommend that you watch and read parts 1, 2 and 3 of this series before continuing with part 4.

Managing Loudness

In this fourth episode of the series, we’ll be taking a look at managing loudness in your Dolby Atmos Home Entertainment mixes.

There are a myriad of plug-ins available that help you automatically comply with loudness regs. However, these rely on you knowing the exact output configuration that you are delivering, be it stereo or 5.1. And this is where the issue with Dolby Atmos lies.

Firstly, if you are delivering in the “single file” format that is preferred by most international distributors, which automatically adapts its playback according to the capabilities of the playback device, then there is no offline process available to automatically gain loudness and true-peak compliance.

No Automated Workflow

Mastering to Dolby Atmos is a linear real-time process, plus you have no control over what specification your listener’s system is. Looking at the various consumer devices available on the market, there are seventeen possible loudspeaker configurations for playing back Dolby Atmos Home Entertainment mixes – 2.0, 2.1, Binaural, 3.0, 3.1, 3.1.2, 5.0, 5.1, 5.1.2, 5.1.4, 7.0, 7.0.2, 7.1, 7.1.2, 7.1.4, 9.1.6 and even AmbiX. Quite a staggering list!

The genius of Dolby Atmos is that it can adapt automatically to all these formats, but the big problem comes when trying to deliver a mix that’s compliant with common technical requirements, and which translates well between all these possibilities.

Dial Norm

The most commonly used loudness standard for OTT distributors, like Netflix, that carry Dolby Atmos is the “Gated Dial Norm”. This makes sense as across all the different possible listening configurations, one thing stays the same - the loudness of the dialogue, as it predominantly comes from the centre speaker (or phantom centre in configurations such as 2.0).

I much prefer to use VisLM by Nugen Audio for measuring this, as it is the most intuitive display of your loudness history I have found and has proved to be the most reliable and accurate. When it comes to complying to the varying technical delivery requirements around the world I find it much easier to do my own fold-downs and 5.1 masters using the rerender workflow as we detailed in episode 3. There will be even more detail on this in our “Mastering” episode, coming soon.

Free Tutorial Series

To learn how to keep loudness under control in your Dolby Atmos mix sessions, watch this fourth episode of our exclusive tutorial series:

Next Episode…

In the fifth episode of this series, we’ll be looking at using 7.1.4 upmixers and reverbs, and why having a .4 height channel arrangement helps you to not break the first rule of surround sound. Be sure to check out the next episode of this free exclusive tutorial series.