I'm afraid I don't really know for sure.... It's very clever though. If I had to guess, I think it's about taking a track and then basically moving out around the sound Scape from left to right (or right to left) increasing and decreasing the volume to give the effect it's circling moving closer and further away, all done in some clever audio program I would imagine. I'm sure there are videos on how to create it on KZbin though, there's a video on everything😁