The Xperia Z3 makes a sound to let you know it has successfully connected when you place it on its charging dock.
If you’re like me, you set your phone to charge just before you go to sleep. If there’s someone already asleep in the same room, it can get troublesome and you may want to disable the dock-charger connected sound.
Note: There’s no on/off button for this sound so this is a kind of workaround.
How to Customize Your Sony Xperia Z3 