When the solver detects that the game is no longer winnable a notification sound will be played. The implementation works so far. When the solver detects that a game is no longer winnable it will raise a signal notWinnable() from dealerScene. The mainwindow picks it up and plays a sound over the soundEngine. It's possible to toggle Sounds and this notWinnable sound separately in the settings menu.
Better sound file (I used a notification sound from Oxygen)
Better text for settings menu entry