It looks like he’s pathfinding within a 3D voxel grid, probably. You’ll also need some kind of pathfinding to pull something similar off. If you can use a similar voxel grid then pathfinding is trivial via A*.
doesn’t sound like you’d need to pathfind, just floodfill distances saved to a 3d array, and indexing into the array with the camera position.
then depending on the value of the cell, making the audio more or less muffled.
not sure how to make the actual muffling but maybe there’s something here Dynamic Effects | Documentation - Roblox Creator Hub