Place a cube A and sphere B far apart but still in visible distance.
Add ability to be able to hear sound 'sA' when in the radius of an object A.
Add ability to be able to hear sound 'sB' when in the radius of an object B.
Following resources can be very helpful:
psai® Music Engine - https://www.assetstore.unity3d.com/en/#!/content/29347
It can be used to change music when entering or exiting a castle. It is recommended that the sounds are location based so that user has a specific music linked to the certain areas in the palace.
possible additions:
Give user the option to set the music and volume.
Following resources can be very helpful:
possible additions: Give user the option to set the music and volume.