Issue link: https://digital.copcomm.com/i/1277927
68 S U M M E R 2 0 2 0 I C A S Q U A R T E R L Y spherical image of the sound field, including height information. The ambisonic mix, when played back in the Oculus headset, would render the output to head-tracking binaural audio based on the positional data from the headset. So, when you hear something coming from your left and then turn to look that direction, now the sound is in front of you. A simple First Order Ambisonics (FOA) signal will be four channels designated W, X, Y, and Z. The first channel W is an omnidirectional pressure-gradient channel, X axis is a front/rear figure 8 pattern, Y axis is a left/right figure 8 pattern, and the Z axis is the top/bottom figure 8. Building off FOA, Second Order Ambisonics (SOA) is nine channels, Third Order Ambisonics (TOA) is 16 channels, and so on. As the channels and order increase, so does the spatial resolution and accuracy. Ambisonics is both a type of microphone for recording, as well as a multichannel delivery format. We used ambisonic microphones like the Core Sound Octomic (hybrid SOA) and Zoom H3VR (FOA with built-in recorder) for recording ambisonics in sync with picture—and also for wild ambiences. I decided to use Pro Tools Ultimate and Facebook 360 Spatial Workstation as my primary tools working in TOA, along with plugins such as Harpex-X, Blue Ripple, Flux EVO Channel, DearVR, iZotope, and FabFilter. POST The post process starts the same as traditional media: receive an AAF/OMF file and picture-locked video from the editor. In this case, I also got SFX stems that had some slow-motion sounds. The video reference file would get converted to DNxHD to use in Pro Tools, and also an MP4 version to later preview inside a headset after mixing and encoding. First steps are always to bring in the files and organize the session to make sure you have everything and are set up for success. Then I will meticulously go through the dialogue and edit it so there is no bleed between the lavalieres. It is vital that the lavs are as clean as possible because when I later go to spatialize the sounds, you will hear sound coming from the wrong directions if there is bleed. On set, I had this conversation with Gavin and Dan to try their best to not talk over one another. They tried their best, but there are many times when they are reacting and joking with each other that there is "steppage." Once the dialogue feels clean enough, then I will start balancing music and SFX stems. Then we are ready to start moving things around in the spatial environment.