The sound: The Copenhagen Metro is very quiet and the recording you hear is where the train is standing still. That's why the recording you hear is so clean and crisp - and the sound is actually surprisingly good in the Copenhagen metro. We did this deliberately because we feel that a good sound experience is vital when trying to portray the actual experience that day. Further to the main recording, when the train was standing still, the recordings from the cameras was, as far as possible, mixed into the sound.