C.2) Sound

The opening scene mainly uses non-diegetic sound to convey the intended mood of the film to the audience. This however does not begin until the one minute mark.
For the establishing shot hovering over the city the sounds heard are diegetic sounds of the cars below on the bridge followed by that of a train's horn and the train moving along the tracks. The train's sounds, like the whole shot itself is used to break up the quiet diegetic sound of the establishing shot to the fade in of the song 'Stayin Alive' by the Bee Gees. The music instantly connects with modern audiences because of its timelessness and its connection with the disco era that the film came out. However, at the time of the release of the film the song was used as it was a #1 hit and was one of the most recognizable songs for worldwide release. If the audience was not familiar with the song the effect would be a lot less powerful. Tony bopping along to the beat and his footsteps in time with the drums would not create the same amount of personal connection to the character.
You could say that the lyrics of the song embodies what Tony is about. The song opens with the lines 'Well, you can tell by the way I use my walk, I'm a woman's man: no time to talk.' This foreshadows Tony's character believing that he is a bit of a player and even within the first few minutes the song is playing he tries it on with those girls. The lines 'got the wings of heaven on my shoes. I'm a dancing man, no time to lose' go along with the theme of the movie - being a dancing musical film and more specifically Tony being the main dancer and having magical dancing feet. Finally the lines 'Life goin' nowhere. Somebody help me. Somebody help me, yeah.' Can foreshadow the film dealing with Tony's difficult life. During the film, his boss (Dan Fusco) fires Tony when he asks for the afternoon off - Tony gets told no however then takes it off anyway in a rage. When he returns to the store Dan admits he over-reacted and says that he does not want to lose Tony as an employee. He motions around the room and lists the amount of time that the other employees have been hired with him in that same store. This was upwards of 16 years for two and you can see by Tony's facial expression that he realises his job isn't as great as he thought, he doesn't want to still be there when he hits 40.
As a whole the lyrics 'Stayin Alive' can connect with New York and the general population at the time. In 1977 New York had a citywide blackout on July 13 - July 14. The power outage resulted in looting and arson especially in the Puerto Rican community. People were stranded in the subways resulting in 4000 people needing rescue and the airports were closed. The city basically shut down for a whole day. This came as New York were already suffering in a severe financial crisis and worrying over the 'Son of Sam' murders. All of the New York residents were, while struggling, simply trying to stay alive in the city.
Both times that Tony interacts with others (dialogue, pizza store plus layaway on shirt) the music fades down so that the focus shifts from the dancey, bopping feeling in you and Tony to focusing on what he is saying to the respective parties.

Interestingly there is very limited diegetic or non-diegetic sound outside of these interactions besides the sound of Tony's footsteps and the Bee Gees song. This again ties in with the use of camera angles and shots so that you focus on how he is moving with the music and so that the feeling evoked by the intro isn't intererupted by shouting or a loud car horn etc. If the feeling were to be distracted the audience would take too long to reconnect with the feeling before the movie properly begins.

Lyrics:

http://www.lyricsfreak.com/b/bee+gees/stayin+alive_20015578.html