I also thought of something, the ambient would change from city for example, to night using the day/night cycle.
If I can find a way to do that, I'll look into something like that.
Minor update recently. It now plays the sound on the position of the person who executed the command.
This is because, say a server has a low draw distance for fog, and the build is far away from the center of the map. Players who dont spawn by the "sound" wont ever hear it. However, if you type the command near the spawnpoints, they only have to "see" the sound once, and they'll hear it until it's changed.