This is basically the same question as this unanswered question.
In Unity 4.3.4f, I have an 2D Audio Source attached to an Empty Game Object that has “Play On Awake” checked. This is the background music for the Scene. Volume is set to 1. I also have a sound effect that is triggered via a C# script using AudioSource.PlayClipAtPoint(). Whenever this sound effect is triggered, the volume of the Empty Game Object is immediately reduced, although the volume remains the same in the Inspector. The volume then gradually increases back to its previous level (again, the volume in the inspector is still 1) over apprx. 10 seconds. Would anyone have an idea as to what is going on? Thanks for you time.