How to play sound when around a region?

[Alpha-G]

I want to play an alarm sound when around this area and I also want the sound to gradually fade away when my screen is moving farther away from that region. The same can be said when I'm moving closer to the region and the sound is gradually increasing but how?

 

[Izzetin]

You can just import an Alarm sound. make it a 3d sound with cutoff distance.
Then place a region on the ground and add the sound to it.
Now it should appear when getting closer and cutoff while walking away.

 

[Alpha-G]

You can just import an Alarm sound. make it a 3d sound with cutoff distance.
Then place a region on the ground and add the sound to it.
Now it should appear when getting closer and cutoff while walking away.

What should I type in the cutoff distance?