A long term solution for this issue is under investigation but a workaround is available by using an Aggregate Device in the Audio Device page of Audio MIDI Setup comprised of the Dolby Audio Bridge and the external hardware. 


Follow the steps below and see attached screen grabs:


Note that to prevent a feedback loop the number of outputs from the Renderer cannot exceed the number of physical outputs of your physical device.    This includes speaker outputs and "live" re-renders.


Method 1 -  For using an external device clocked to the Dolby Audio Bridge

 

  • Open Audio MIDI Setup from Applications/Utilities/Audio MIDI Setup.

 

  • Create an Aggregate Device via the + icon in the lower left of the Audio Devices window.

 

  • This Aggregate Device should select to “use” the external device (selected first) and then the Dolby Audio Bridge.

 

  • Ensure the “drift correction” is checked for your external device  

 

  • Set the Clock Source for the Aggregate Device to the Dolby Audio Bridge.

 

  • In the Dolby Atmos Renderer Preferences/Driver set the Audio Output device to the newly created Aggregate Device.       

 

Method 2 - For using an external device clocked to an external source such as word clock or video reference.   For this use case an Aggregate Device must created for BOTH the Renderer Audio Device Input and Output.  The external device itself can be set to internal or clock an external source i.e. AVID HDX hardware clock to incoming Work Clock or Video Reference.    Follow the steps below:

 

  • Create an Input Aggregate Device via the + icon in the lower left of the Audio Devices window

 

  • This Aggregated device should select to “use” the external device (selected first) and then the Dolby Audio Bridge

 

  • Ensure that “drift correction” is not checked for the external device or the Dolby Audio Bridge

 

  • Set the Clock Source for the Aggregate Device to the external device

 

  • Rename the device Aggregate Input or an alternative name to distinguish it from the output Aggregate Device

 

  • Create an output Aggregate device as describe at the beginning of the post 

 

  • Rename the device Aggregate Output or an alternative name to distinguish it from the input Aggregate Device

 

  • Set the Clock Source to the external device

 

  • Ensure that “drift correction” is enabled on the Dolby Audio Bridge

 

  • In the Dolby Atmos Renderer Preferences/Driver set the Audio Input device to the newly created Input Aggregate Device and the Audio Output device to the Output Aggregate Device

Note: If you wish to clock your external device from an additional external clock, use the software for your device to set this preference.