Spat Revolution and Dolby Atmos workflow
Many users have asked us about the major differences between FLUX:: Immersive Spat Revolution and the Dolby Atmos Production Tools. Particularly with Dolby’s increased focus on music and emphasis on online distribution services for independent artists, questions regarding comparing the two platforms often arise.

Can both these production tools be compared, and what are the Advantages?
This article focuses on Spat Revolution, a standalone application (with its integration plugin suite) and how it differs from the Dolby Atmos Tools. Hopefully some of the information in this article will help demystify the hype – The object-based immersive production hype!

At the base Dolby Atmos is a proposed workflow and a specific deliverable for Dolby Atmos speakers arrangements. One thing we need in immersive productions is good intuitive workflows. The current boom in immersive productions has triggered a greater need for well designed and efficient workflows – multiple creation and diffusion tools working in unison.

Dolby offers integration with selected DAWs, while Spat Revolution endeavors to offer wider options with more plugin formats supported. That said, Dolby offers the ability to create an ADM master, a recognized proposed standard agnostic of the actual format (the object base mix itself). More on this later.

The proposal
Dolby (and others) are offering commercial solutions where much has to do with licensing, for example, the streaming/distribution services for delivering Dolby content. (e.g., Dolby Atmos theatre venues). Sony Music has their approach here as well for delivering Sony 360 content on various platforms. This is a key spin on these proposals.

Some differences
A number of differences can be found between Spat Revolution and Dolby Atmos production tools. While we won’t directly compare something as subjective as sound quality, Ircam’s 30 years of research and expertise have made Spat a very high-level technology. With regard to format possibilities, spatialization technologies, adding room simulation, flexible workflows, adapting to various industry domains and deliverables, the two are simply different beasts. They are different but as well can be very complementary.

Object-mixing rendering and formats
Dolby Atmos Production Tools is ultimately an object mixing renderer that outputs a specific speaker arrangement family (Atmos), while Spat offers a wide range of pre-defined common arrangements as well as custom ones. This simply means that you can create for a wide range of configurations for various deliverables, up to a custom immersive installation.

Monitoring on your speaker arrangement or on headphones
Monitoring your object-based mix in a different environment than the deliverable is easy with Spat Revolution; this is great for those situations where you have a smaller or larger monitoring setup. For example, you can monitor on your available system, using a separate virtual room with a different format but with the same object mix, while in parallel rendering your actual deliverable (including an Atmos mix or any other format). Using Spat’s binaural monitoring, also makes it possible to virtualize any speaker arrangement on headphones.

Binaural for headphones
We can highlight possibilities with binaural overall in Spat Revolution, like dealing with HRTF libraries, personalized HRTF, various binaural modes, some not around HRTF, such as Snowman and Spherical models. Dolby does offer some binaural implementation too and has lately worked on this front facing the reality of our audience being isolated on headphones more than ever.

Panning and technologies
In terms of panning algorithms, Dolby utilizes a layer-based approach (LBAP in Spat) which is more forgiving, as opposed to Vector based panning (VBAP), which can sometimes be challenging with non-uniform systems. In all cases, a wide variety of panning options are available in Spat, where Dolby is a fixed panning model. I might mention that both layer-based approaches may not be *exactly* the same. This panning is a good way to work with a speaker elevation layer. The .4 for example that complements your base 7.1.

Acoustic simulation (reverberation)
While Dolby is primarily a panning tool, Spat Revolution brings room acoustic simulation (reverberation) to the virtual spaces where the object mix is done. Much of immersive audio is dependent on how sound is perceived in the real world, and the room effect of Spat helps to reinforce the localization and other aspects.
Consider the possibility of localizing the simulated early reflections of each source object; It brings a huge sense of reality. We can say that Spat goes deeper in source/object properties overall (Many options beyond object position such as perceptual parameters). You can use as little or as much as wanted.

Ultimately, Spat will allow you to create any deliverables, including Atmos, Sony, DTS, or custom sound installation. And it works in stereo too. In fact, Spat can deliver even a scene-based ambisonic mix (agnostic of the speaker system), to be decoded down the line. In addition, Spat Revolution can decode Ambisonic as well.

Regarding agnostic deliverables (channel-based or renderer agnostic), Dolby supports exporting an ADM master from your audio creation workflow. This means, for example, that you can import this object-based mix (ADM BWF.wav audio file with metadata) into a tool such as the Ircam ADMix player and render the various formats with the various technologies. The OSC integration in this player makes it possible to drive the dynamic and static objects in the external renderer. We in our team have done this with Spat Revolution acting as that external renderer.

ADM-OSC – Production tools and how they can be complimentary
Thanks to FLUX::’s involvement in the ADM-OSC initiative, some DAWs now support the optimal integration of external renderers by mapping their panner bidirectionally instead of via plugins. This was added by Nuendo and Merging Technologies at the end of last year, with others expected to follow.

With this, the renderer, such as Spat Revolution, offers a nice integration with the DAW, and since some DAWs can import ADM masters, you end up with an object-based mixing environment that is renderer format agnostic (even if the original creation was made in the Dolby environment).

This shows how a project can start with a creator or mixing in Dolby atmos workflow, but where the production needs to render other formats later. You can think of the opposite scenario where Spat Revolution is creating some audio, 7.1 or 7.1.4, beds with acoustic simulation, and that the prints then get inserted in a complete Dolby production workflow.

The ADM-OSC initiative mentioned above started for the live production side of the immersive wave – From audio capture to live broadcast workflow (where OSC is the main protocol in this industry already)!

Building ecosystems from creators to the distribution and diffusion!