on AirDroid, when a connection is being started between your Android phone and PC, your are notified by a sound. To disable notification sound on AirDroid or Enable it, do as follows:
1. Open AirDroid
2. Go to "AirDroid settings"
3. Mark on Unamrk "Notification Sound" to Enable or Disable the sound
4. You can also show or hide the notification icon by marking or unmarking "Notification Icon"