INTRODUCTION

This document has been designed to guide you through processes to create a consistent set of parameters that all Engineers can follow to satisfy UMG DOLBY ATMOS AUDIO SERVICING ASSET SPECIFICATIONS and DOLBY ATMOS AUDIO ARCHIVAL DELIVERY REQUIREMENTS. Please note, this document does not assume that you are the original stereo Engineer/s of the tracks and/or working directly with the artist or original production team. 

SETUP

Ensure the following are set in your DAW session:

• You should be working with a minimum 7.1.4 speaker configuration and ensure mixes are reviewed in headphones and in 5.1 (on a consumer system and/or re-render in studio).
• All speakers set to the same reference level – a Dolby Atmos for Music mix is a “nearfield” mix, and the most common monitoring levels are 79db or 82db SPL LCS (Slow, C-weighted).
• 5.1 and 5.1.x downmix is set to “Direct Render”. This offers a more accurate representation of your mix when playing back on lower speaker count configurations.
  • We also recommend setting “Trim controls” to “Manual” and “0 dB” / “0 %” in all configurations (5.1 and 2.0, 5.1.2, 7.1, etc).
• LFE has LOW PASS filtering applied with linear phase, in the range of 100-150Hz on your input and with a slope in the range of 18-24db per octave.   
  • Assign LFE information via an auxiliary send using a plug-in to apply filter.
  • You cannot print full range signal to your LFE channel.  
  • LFE filtering must be in addition to any filtering applied to your monitoring path.  

Ensure the following when printing a Dolby Atmos ADM BWF:

• All unused “empty” objects are disabled. 
• All active beds and objects are unmuted. 
• The Dolby Atmos mix and associated stereo master exactly match in duration.  
• Loudness and True Peak levels must adhere to our specifications (link below)

Additional notes:

• There are no specific requirements on distribution between beds and/or objects. 
• Please review the UMG DOLBY ATMOS AUDIO SERVICING ASSET SPECIFICATIONS for Dolby Atmos technical requirements.

RECOMMENDATIONS

This section aims to support you in your workflows based on our learnings from the past years of working with Engineers during the Dolby Atmos mix and Mastering process.

GETTING STARTED

• Ensure your room is regularly tuned and that you are regularly monitoring metering on the Dolby Atmos Renderer.  
• Upon receiving assets, review for missing or incorrect elements, varispeed and/or EQ and balance issues referencing the mastered stereo audio prior to commencing mixing, in case you need to request new parts.  
• Explicit / Clean versions: In most cases it will be stated, but if you are working with a track that is clearly explicit in its audio and not stated as such in documentation, please check with your Label contact to confirm if a clean is required (and if so, to then request the correct ‘clean’ audio – stems/multis & stereo master for reference).
• On occasion, an Engineer may be provided with stereo masters from incorrect sources, such as the CD version or pre-mastered mixes, which may differ from the digitally streamed version. If you suspect an issue, please check with the person who provided the masters to you. 

MIX APPROACHES

• We recommend mixes include audio information across the full X, Y and Z planes.  Your workflow can change to suit the respective genre or track.
• UMG will review Dolby Atmos mixes to ensure a quality experience with meaningful format engagement. There are many ways way to create music in Dolby Atmos, however, there are some practices that are unacceptable and which will result in submissions being rejected. Some of these practices include:  
  • Placing only a Stereo (2-Channel) music mix in a Dolby Atmos container, such that only two outputs are active.
  • Upmixing or routing a stereo mix such that full-program material is audible in every output channel of a Dolby Atmos mix, or that the same material is substantially present in every channel. 
  • Utilization of source separation instead of stem or multitrack assets, when such assets exist. It is important to ensure all potential avenues for stem or multitrack asset research have been exhausted.
    • Should you have to resort to source separation, know that the technology may produce problematic artifacts which could result in your mix(es) being rejected.  
• We suggest that you think critically about center channel vocal placement. We have observed artists feeling a sense of narrowing of their vocal, especially when mixing from wet stereo stems. 
• Review your LFE levels and filtering:
  • LFE is available for low-end extension, however it is optional and may not be necessary for every mix – this will be dependent on the genre, artist or track.
  • A properly calibrated environment will give a good response of LFE on most systems. Regularly mute the LFE channel to ensure the mix holds up without it. The LFE channel should be treated as an enhancement for low frequencies – not providing the primary low frequency for the mix.
  • Do not send full range signals to the LFE channel by ensuring that a low-pass filter at a maximum of 150Hz is applied (see Section 2 – Setup for more information).
• When an associated stereo master exists:
  • Retain the stereo master in your DAW session to allow you to reference the intention / balance of the original work as you craft your Dolby Atmos mix. Ensure the stereo reference is routed through the same monitoring chain as the Dolby Atmos mix for a consistent reference.  
  • A/B against the stereo master throughout to ensure you are retaining the integrity of the original creative intent. Balance of elements can shift when moved into the immersive space, so it is important to continue to reference the associated stereo master as you build your Dolby Atmos mix. 
  • You must match the timing/duration of the associated stereo master.
• Be careful when adding reverbs to create space, as this must not overpower the essence of the original mix.
• As well as referencing on a minimum 7.1.4 system and headphones, we recommend referencing 5.1.x re-renders to ensure the intention of your mix is presented correctly, but also ensure the room is calibrated to this configuration (if switching from a higher speaker count).

CONTINUOUS PLAY / GAPLESS PLAYBACK PROJECTS

Ensure you have checked if any tracks on an album project are gapless. If they are you may want to consider the following options depending on your software / hardware workflow.

Option 1:

• Mixing the respective tracks in one session.
• Printing the whole session, importing the resultant ADM BWF into the Dolby Atmos Album Assembler, and then lining up the print with the stereo album tracks and exporting the ADM BWF tracks out based on the stereo album track markers.

Option 2:

• If the above considerations are not possible (e.g. tracks were mixed after knowledge of gapless transitions), then you will need to import the respective ADM BWFs into your DAW and line up the transitions. Please note however, not all DAWs allow full importing of the ADM and its respective panning and binaural metadata.

In all cases ensure the specific element/s that move into the next track: 

• Are assigned as an Object.
• Will not clash with another element assigned to the same Object number on the following track.
• Retain the same Binaural Metadata parameters (Binaural Metadata cannot change on a given Object).

Depending on your preferred DAW, you may find this resource useful.

BINAURAL METADATA

You must incorporate Binaural Metadata into your master.

• This is utilized by Streaming Services to provide an immersive experience when the user is listening on headphones.
• All algorithms have the ability to be updated and improved upon, however your master is locked and if you have opted for limited to no Binaural Metadata then your Binaural mix will not benefit from such updates. 

Binaural Render Mode is a feature of the Dolby Atmos Renderer which allows you to apply a distance model via metadata to each of the Object and Bed Channels in your Dolby Atmos mix. This is only relevant to the Binaural render of your mix and your headphone monitoring feed – it does not apply to speaker processing.

The various Binaural render mode settings (Off/Near/Mid/Far) are intended to give varying levels of spatialization to each of the objects or bed channels to which they are applied.  Near/Mid/Far settings are measures of the virtualized distance between an object or bed and the listener’s head.

While you mix, try changing the position and Binaural render mode settings for each of your elements. Our experience has shown that some Engineers feel that they can achieve a mix that works across both speakers and headphones more quickly if they approach the headphone mix first, and then adjust the mix while switching between speakers and headphones. There is no right or wrong way, and we encourage you to experiment. 

It is highly recommended that you adopt a Binaural Metadata template in your workflow.

• You will be able to complete a mix faster if you are applying an element to an Object with the chosen Binaural Metadata parameter from the start. If you find through your mix process you wish to change the Binaural Metadata parameter, you reassign an Object.  
• This will help you if you are working on a gapless play album or a consistent piece (such as classical works) where all elements are constant track-to-track. By retaining a universal template, you can assemble tracks together, when required, without having to repeat the Binaural Metadata step by either importing or manually adding the Binaural Metadata again.
• We recognize that it may not always be possible to create a Binaural Metadata template (such as in Apple Logic Pro Renderer integration), in which case you can adopt a DAW session template instead. 

To provide an optimal mix for headphone listeners, it is recommended you work with headphones throughout the mixing process. You can start your mix in speakers or headphones, but it is critical that you incorporate headphone monitoring as you work.

Additional points to consider and explore: 

• Setting the Binaural Render Mode is not automatable and cannot change throughout a session.  
• The OFF setting removes binauralization. Applying this to every element would essentially create a stereo render of your mix. It is prohibited to be universally applied across elements and will result in your mix failing technical QC. Therefore, please be mindful of how and when you apply the OFF parameter. 
• We encourage you to utilize Dolby’s personalized HRTF (PHRTF). This allows you to create a personal profile based upon a scan of your head, to help you perceive the binaural experience more accurately. Further details here.
• Review Object placement – placing objects in the very center of the room results in no binauralization on the headphone output (Binaural Metadata will have no effect) and can also create unpredictable performance on different speaker configurations. 
• If your aim is to create a dry center front image, try positioning the object on the front wall and setting the Binaural rendering mode to ‘Off’ or ‘Near’. 
• You can use the Binaural renderer plugin directly through your DAW, where available. 
• Binaural Metadata is as important as your main speaker mix. Although all ‘MID’ is the default set by the software to ensure there is some Binaural Metadata contained, it is not commonly found to be the optimal headphone experience. You are encouraged to experiment with different Binaural Metadata settings. 
• Some Engineers have found moving to an Object-based approach allows for more specificity in the Binaural Metadata parameters rather than global application of one parameter against several elements contained within a bed channel. 
• When utilizing multiple beds, each common channel will have the same Binaural Metadata. 

MASTERING

Mastering can be accomplished via various software packages including, but not limited to your DAW, the Dolby Atmos Renderer, the Dolby Atmos Conversion Tool and the Dolby Atmos Album Assembler.

Dolby Atmos Mastering is generally applied utilizing the same tools available to the Mix Engineer.  The Mastering process may therefore be conducted by the Mix Engineer or a separate Mastering Engineer. Do not assume that any additional mastering work will take place after you have delivered the Dolby Atmos mix, and confirm with your label representative if you are unsure. 

Useful resources can be found here.

DELIVERY

For delivery information please follow the information outlined here: UMG DOLBY ATMOS AUDIO SERVICING ASSET SPECIFICATIONS and DOLBY ATMOS AUDIO ARCHIVAL DELIVERY REQUIREMENTS.