// Use this for initialization
 void Start()
 {
     _instance = this;
     audioCrossFadingManager = AudioCrossFadingManager.Instance;
     isStopping  = false;
     audioSource = GetComponent <AudioSource> ();
     scaledRate  = Constants.crossFadeRate * Constants.musicVolume;
 }
 void Awake()
 {
     _instance         = this;
     _audioCrossFading = false;
 }