3d sound

You know when you wanna add a sound in your map as a 3D sound you simply can do: But sometimes you can't do that: Since I have not seen anyone explain how to fix this, now I will tell you how I did it: You need a program that can edit sounds or music or videos for do this, I will use...

I have a trigger that it attaches 3D sound to unit that loops itself as default sound for the unit as it stands moves or whatever it does, but whenever it attaches the same sound on another unit the previous sound stops.