I want to make an AR scene that has sound that is spatialized, so that the sound gets louder the closer the user gets to it and quieter if they move away. Is this possible?
It is possible!
Check out this article on how to add spatialized sound in Unity:
Essentially, you can attach a sound file to a 3d object in Unity and then upload it as a prefab to STYLY. Make sure to pay attention to the 3D sound settings. Particularly the min and max distances. Remember that these distances are in meters, so generally speaking you probably don't want to have your max distance (the distance at which the user cannot hear the sound) set to something larger than 10-20, unless your AR experience is really really large.