Topics covered in this article:
- Dolby Atmos Music Delivery Specifications
- Dolby Atmos Music Incoming Mix Deliverables
Dolby Atmos Music requires a very specific delivery specification to be met in order to ensure proper reproduction across all forms of playback systems and content services.
The following outlines general deliverable requirements for Dolby Atmos Music.
- All deliverables must:
- have been approved for home listening and monitored in a room with at least a 7.1.4-ch speaker layout.
- be created with a timecode of 24 fps.
- be provided as an ADM BWAV file that conforms to the Dolby Atmos Master ADM profile.
- use 24-bit PCM resolution at a sampling rate of 48 kHz.
- be conformed and synced to the corresponding stereo deliverable.
- contain no additional silence at the start of the deliverable when compared to the corresponding stereo deliverable.
- For individual tracks that are not part of an album, the duration of any additional silence present at the end of the deliverable must be less than 1 frame (2,000 samples at 48 kHz) when compared to the corresponding stereo deliverable
- All deliverables must not:
- Exceed 128 PCM Channels
- Exceed 118 objects in the ADM BWAV file
- All deliverables should:
- also have been monitored over headphones with the headphone render mode set to “Binaural”.
- Include a DAMF (Dolby Atmos Master File) if delivering for archiving at 96kHz.
- have the Binaural Render Mode setting (Off, Near, Mid, Far) specified for each Bed Channel and Object.
Note that at present, the Dolby Atmos Music workflow requires editing at frame boundaries, which may result in an offset in start and/or end compared to the corresponding stereo deliverable.
- For album deliverables where gapless playback is intended between tracks:
- each album track MUST be delivered as an individual ADM BWAV file.
- each track SHOULD be exported by specifying In and Out points from a single project that contains the entire album.
- each track boundary MUST be no more than half a frame (1,000 samples @ 48 kHz) earlier or later than the same track boundary in the corresponding stereo deliverable.
- there MUST be no additional silence at the end of each track when compared to the same track from the corresponding stereo deliverable.
- For individual tracks, all deliverables must achieve an integrated Dolby Atmos loudness that does not exceed -18 LKFS, based on ITU Recommendation BS.1770-4.
- Note that integrated loudness values lower than -18 LKFS are permissible to enable wider dynamic range content; for example, classical or jazz.
- For individual tracks, the amount of peak limiting indicated for binaural headphone playback should not exceed 3 dB.
- For albums, integrated loudness must be measured on each individual track, rather than the overall album.
- All deliverables must achieve a True Peak measurement that does not exceeed -1 dBTP.
Independent DAW Requirements
- The session should contain all the original elements found in the master mix.
- Unused or alternate takes/tracks/regions need to be muted.
- Do not use mute buttons or automation, rather mute regions in the timeline.
- Audio Files to be supplied as WAVE PCM format at a sample rate of 48kHz or 96kHz/24bit (96k mix is possible, however, BWF and MP4 delivery is limited to 48Khz)
- Remove all inactive/unused tracks from session.
- Remove all unused audio files from bin
- Name all tracks and regions
- If possible, use VCA groups instead of audio groups for volume moves on more than one track.
- Provide tempo if known
- Stereo reference track must be provided. Mastered stereo is preferred.
- Vocal tracks should be provided both wet and dry, annotate reverbs and FX used in comments if known
- Outboard effects used should be printed as stems
- Master buss compression/limiting should be bypassed when creating stems
- Simple track compression and EQ can be “committed”, but send/return effects should be printed on separate tracks for maximum flexibility.
- Individual elements of a group stem, drums and percussion for instance, should be provided as individual stems rather than a bounced group.
Pro Tools Requirements
- Session should be Pro Tools 12 or above
- Save Copy In should be used and Plug-in Settings included
- Tracks should be supplied with plug-in’s ‘committed’ when appropriate (see above).
- IO Settings should be Exported and provided as a .pio file
Logic Pro Requirements
- Session should be Logic Pro X
- Project should be consolidated before delivery
- Alternatives should be removed from the project before consolidation
- Tracks should be supplied with plug-in’s ‘frozen’
- Instrument tracks should be ‘frozen’
- Please bypass master buss compression/limiting before freezing
Dolby Atmos is a powerful mixing solution, the more separation in instrumentation and processing you can make available the more control your immersive engineer will have to create a special mix.
Vocal processing in particular benefits from being split out from the unprocessed signals. Where specific reverbs have been used, providing a flattened (frozen or committed) audio files should be provided. The more effects printed as individual stem elements, the more flexibility goes to the mixer for Atmos panning.
Provided stems should be able to play at unity and match the provided stereo reference track. This will enable the mixer to focus on the immersive mix rather than trying to match processing for the stereo.