In this tutorial from Sreejesh Nair, which was first posted on his Film Mixing And Sound Design blog, which we repost here with permission, Sreejesh takes us through how to use the Dolby Atmos Production Suite and compares it to the workflows using the Dolby hardware RMU. Over to you Sreejesh...
Since the last time I wrote about the Dolby Atmos Local Renderer, there has been an update by Dolby on this. I also got quite a few requests from our readers to cover this too. So, this time I thought I would write on this. I won’t be explaining on the VR workflow in this note as that is not directly related to Film Sound.
Almost coinciding with the launch of Pro Tools 12.8, where Avid introduced the 7.1.2 panner together with one of the tightest integrations with Dolby Atmos workflow, the Dolby Production Suite was launched. The Production suite as the name suggests is a suite of apps consisting of:
- Dolby Atmos Renderer Application for Mac
- Dolby Atmos Panner Plug-in for Pro Tools
- Dolby Atmos Panner Plug-ins for VR for Pro Tools
- Dolby Atmos Monitor Application
- VR Transcoder Application
- Session Templates and Documentation (This needs to be updated for V12.8)
Unlike the earlier Local Renderer, this time, you buy the Dolby Atmos Production Suite from the Avid Webstore and you can do your premixes or Sound Design using this. The purpose of this Production Suite as a local renderer still remains the same as the older one. There are some things that need to be kept in mind about what it is and what it is not.
|Is used for premixes and VR Workflows||Is used for Theatrical workflows or cinema mastering|
|Supports upto 22 outputs||Supports upto 64 Outputs|
|No Bass management for Surrounds||Bass Management for surrounds|
|Audio is sent from the Send plugin and taken back into Pro Tools on a return plugin. So can’t compensate for ADC||Audio is sent directly via MADI to the RMU so ADC is taken care of.|
|Has to be run on the same system therefore can put a bit of CPU load||Is independent so no CPU issue|
|Will take up more auxes on the Pro Tools session||Is not dependent on that|
|Can do Offline renders from the MXF for various formats||Can’t do offline renders|
So, with this, you still need to keep in mind that it is NOT meant for full fledged theatre or cinema workflow. For that, you would still need a Dolby Approved mix room and the hardware RMU.
The signal flow for this remains the same as what was with the earlier Local Renderer. There are some minor changes as before the renderer app was hidden from view to the user and the room modes were something that you would set up when you installed it. (Is it 7.1.2 or 7.1.4 etc). The Number of outputs compared to the earlier Renderer have also increased to 22 from the earlier 16. The basic principle of the renderer still remains the same as my the earlier blog entry.
There are some changes that you need to keep in mind when working with this version:
- The Renderer Input and output are renamed to Renderer Send and Renderer Return. This is a welcome change and will definitely remove the confusion that prevailed earlier of whether it was the input to the renderer or input from the renderer.
- Multimono Plug-in If the Renderer Send can be inserted on a 7.1.2 Aux.
- It includes VR which shouldn’t be used unless you are working on VR. This also requires that you change the Atmos Renderer to VR Mode.
- You now have the ability to also have Re-Render returns to Pro Tools if you want to record down-renders of your stems.
- The renderer Return also has Headphone returns that will provide you with a Binaural Mix of your Atmos mix if you are using Headphones to track. Make sure you enable Binaural Monitoring on in the Monitoring tab. At this stage also remember that every feature you enable will take up CPU usage as the renderer has to do that calculation as well.
Dolby Renderer Application
The application in itself is one that acts as an interface and loads HTML pages (present in the app) internally to connect to the various tabs. It is almost an exact replica of the RMU page with a few changes when it comes to Mastering and Room modes etc.
This is the page you land on when you start the application. I will explain some of the features here. But before you reach this, there is a config you need to do based on the room setup and number of speakers you have. But since we are here, I will explain this tab.
The Drop Down menu where it says physical will switch the monitoring from your existing config to 7.1, 5.1 or 2.0. You can create your custom monitoring too by going to the Room Tab and choosing to monitor in that to edit. Just below this is where you can see your current room layout. Although this figure shows the maximum number, you really don’t need this unless you have that many speakers. On the right, there is an option to use Spacial Coding for Monitoring.
On the right, there is an option to use Spacial Coding for Monitoring. This is derived from the way Bluray is encoded. In a Bluray, the 118 objects are condensed to fewer elements. This is done by grouping sound elements into clusters that occupy the same positional space and pushing that to the speaker output. This reduces the number of channels needed to encode. This same principle is used in this case too. If so, why is that an option to turn on and off? The answer is simple. You only turn it on if you are working with full mixes like QC or editing a full mix session etc. If you are doing Track-Lay or Sound design etc, it would be better to turn it off because otherwise when you pan you may hear positional artefacts because of the way the algorithm functions.
Below that you have the options you can choose when monitoring stereo or 5.1 and is fairly self explanatory. The formula that is used in the downmix is as follows:
For Stereo Downmix:
Lt = L + (–3 dB x C) – (–3 dB x Ls) – (–3 dB x Rs)
Rt = R + (–3 dB x C) + (–3 dB x Ls) + (–3 dB x Rs)
Lt/Rt (Pro Logic II):
Lt = L + (–3 dB x C) – (–1.2 dB x Ls) – (–6.2 dB x Rs)
Rt = R + (–3 dB x C) + (–6.2 dB x Ls) + (–1.2 dB x Rs)
Lo = L + (–3 dB x C) + (–3 dB x Ls)
Ro = R + (–3 dB x C) + (–3 dB x Rs)
The coefficients for a Dolby Pro Logic PLIIx downmix from 7.1 to 5.1 are:
Ls = Lss + (–1.2dB x Lrs) + (–6.2dB x Rrs)
Rs = Rss + (–6.2dB x Lrs) + (–1.2dB x Rrs)
The coefficients for a Standard downmix from 7.1 to 5.1 are:
Ls = 0 dB x Lss + 0 dB x Lrs
Rs = 0 dB x Rss + 0 dB x Rrs
The Room Tab is where you set up the renderer to function based on your Room. In the older version, when you install, you had the option of choosing 9.1, 11.1, etc. That is now gone. This mode gives you much more flexibility to address more speakers and your room. If you look, there are tick boxes that let you choose speaker positions in the room. This will be enabled once you click edit. (It shows as Cancel and Save because I clicked Edit). Once you tick all the right boxes, you need to set up the routing number below in the drop down box. This is very important as this reflects how it is returned in Pro Tools where you have the renderer return.
So for example if you have set up the routing as L:1, C:3 and R:2, in the renderer return within your Pro Tools Session you will route 1 to L, 2 to R and 3 to C. You can change it to be LCR too by changing the routing number in this screen. This is a one time setup that you need to do based on your room, and you also have the flexibility to put up delay for the speakers too. Just beside the Physical tab, you have the Monitoring Tab where as I mentioned earlier, you can create custom monitoring formats.
The Mastering Tab is what allows you to do a QC, create your Bluray Master etc. I am not getting into the nitty gritty of this as it is beyond the scope of the current article, but I will explain some of the features here. The best thing about this is that you no longer need an RMU to play back an existing Atmos MXF file. You can load it into the master file section and then once done, click Set. This will lock the MXF in your renderer. Once that is done, you can simply click Master (the button just below Input on the top) and hear the Atmos mix via your Pro Tools Session if you have the Local Renderer set up. An additional feature this gives, if you are say doing a version mix, is you can load the original mix in this and have the version mix in Pro Tools. Once done, you can switch between Input and Master in the Renderer app to switch between the original and the Version mix to do an A/B. This is a very cool feature. The other major advantage is once you have loaded your MXF, you can do offline renders to 7.1, 5.1 or stereo from that Atmos mix.
Now, keep in mind that the more beds you create, that is going to reduce the number of objects you can have as the Atmos format can only support 128 Inputs. So, if you create three 7.1.2 groups, that takes 30 inputs and you are left with 98 Objects. Now, once you create the groups, you can assign beds to it as well as objects to it. So, if you have been following my blog, I have been mentioning about Object Budgeting before starting a mix. Doing this will mean you have a clear idea of the Object numbers you are going to use for Dialog, FX and Music and assign that too to the group. The advantage of doing this is reflected in the next tab.
This tab will set up everything that is reflected in the Dolby Renderer Return plugin within Pro Tools. From the above screenshot, you can see that you have an option of 64 outputs that you can set up to do downmix or re-renders. Within this, you can set up say the first 8 to be 7.1, next 6 to be 5.1, the next 8 to be the 7.1 of FX+Music, the next 8 to be DX, Next 8 to be FX etc etc. As you can see, in one go, you are able to make full down-renders and create your stems. You no longer need to run everything again just for these deliverables.
Both these options can also be imported from the Main Mix room where you have an RMU and you can then take your mix and do these re-renders in a different room if you wish to do so too.
The Settings tab just provides for a Pre-EQ Gain. This is set to 10 dB. So if your mix sounds 10 dB lesser when you play, just make sure that this is set up correctly. This is done to provide a headroom for Room EQ when it is done.
This tab provides for Room EQ. You can set this up by playing Pink Noise (or other test tones like 100Hz, 1k, 10k, Sweep, Thump etc) and using any Room measurement to find the values to be done for the EQ. Every Speaker except the LFE has a 27 band EQ with Frequency, Q and Gain (-6 to +6) parameters. You can also set the gain for each speaker from -16 to +16 dB. But remember that doing an EQ in this will increase the CPU usage on your system.
This tab is where you set up the renderer to work based on what workflow you are doing. You have to make sure to remember to set it to Home Theatre if you plan on using the Object plugins or Atmos Workflow in Pro Tools. If not, you will get error messages and warnings as the modes are different.
This is a basic overview of the Renderer Application itself. The setup for Pro Tools isn't much different from what it used to be. The good thing is Dolby provides templates for you to start working as soon as you install the Renderer. I am also sharing my personal mix template that I use for my mixes (built on Pro Tools 12.8). Also, remember that the templates are just starting points and get complex or simpler depending on the movie. I have hidden the return Auxes to make it visually less complex.
Make sure you check out and update to Pro Tools 12.8HD. That has changed the way I approach my mix and has made my life extremely and immensely easier and simpler to handle work no matter how complex it is.
I hope this was a useful blog post and as always please share if you found it helpful so that others may too.