Bs turrets in MP did make no sound for some time. Wonko found, if start singplayer one time and then start MP theres an update und sound works. Additional theres a ship symbol besides status bars.Symbol&Sound.jpg
In logical konsequence you have a very high risk to get banned if you play singleplayer and then multiplayer? Or better, if you want to play multiplayer your not allowed to play singleplayer or you get banned?