try thisone...
first step:
you need to define the sound/music you want to play in your mission in your description.ext as cfgsfx class:
class CfgSFX
{
   sounds[] =
      {
         yoursound
      };
   class yoursound
   {
      sounds[]={sound1};
      name = "yoursound";      Â
      sound1[]={"yoursound.ogg", db-05,1, 1, 0, 0, 0};
      empty[]= {, , , , , , ,};
   };
};
with this setting the sound will loop until the end of your lifetime
step two:
go to your mission editor and set a trigger just on the object that should play the sound (radio/tent... whatever)
set triggers fireing condition to true, go to the triggers effect section, and select your sound in the field named "trigger" and voila. save and reload your mission and start it.
you can optimize the distance the sound will be heard by the changing the size of the trigger or optional by changing the "DB" parameter in your cfgsfx description (i.e. db-15).
surely you can name the trigger i.e. radio_1 or something and delete it via the deletevehicle command when the the playing object is destroyed, or cut it off with a action or whatever you want to do.
surely you can use a additional scrip instead of a trigger ...