For Dolby Atmos Mastering Suite setups using Dante and LTC over audio the system latency needs to be determined and the “Audio to Timecode Alignment” field set in order to ensure accurate synchronization to LTC.  

This value is preset for setups using ASIO but should still be tested and adjusted as needed.   

To determine system latency a “spotted” audio source is mastered to the renderer.   The start time of an exported re-render imported into Pro Tools on an adjacent track is compared to the audio source start time by zooming in on the waveform and measuring the distance (in samples) from the start of the source to the start of the imported re-render.   

Tone used as a synchronization 2-pop is suitable for this task but any audio can be used as long as there is no fade in.   To make this task more accurate the sync audio source should be mastered with some pre-roll and spotted back to the session using the same value.