Creating sound fields

I m creating a small game and I use a plane to mark the wind field. When my character enter on the wind field, the plane, with a collision sensor that reacts with the character property, the wind sound starts, but there is a problem, the sound starts but when the character stops the sound stop as well and when I move it again the sound restart.
I want to know how to make the sound stop only when I leave the wind field, maybe there is another way to create that sound field, and maybe you guys know a form to make the sound fade out smothly when I leave the field.
Plese give me a hand.
Thanks in advance.

Hi, without posting a blend file its hard to tell if this can be done as you’d want with logic bricks.
In this case it would be useful for you to post a simplified blend I think.

Though if you want better control you can always use python to manage turning the sound actuator on and off exactly when you want.

here goes the .blend file, its a pretty simple scene,were the player hit the red field and the sound starts, sorry about the weird wind sound, i need something small to post and wave is a huge format, the first problem I solve just making my field falow he ground, But about the second problem I dont know how to solve it.
I want the volume to decrese smotly when I leave the field, not like this abrupt stop that I made.
Thanks for the help till now.