How sound adds to mise-en-scene: Sin City

The sound in the opening to 'Sin City' is a mix of non-diegetic and diegetic sound to present both the atmosphere and location of the film.

 The non-diegetic sounds of the traffic places surroundings to this piece, giving the opening's location a more ordinary feeling, and allowing the characters to appear as though they are in a normal situation. This effect of placing extraordinary events into ordinary situations, allows the audience to feel comfortable for a while and, in turn, will later shock them further. By using the sound of the traffic the audience are familiar to the situation, by establishing this, the director can make out of the ordinary events seem possible. 
The traffic sounds also establish the urban location of the film. This is typical for a film noir often they are set in a large, darkened city the modern, urban sense gives the feeling of strong morals, and often makes the audience feel a clear sense of right and wrong. This is important in thrillers, especially film noir, as they are often crime related.

The music used in this clip, has a jazz nature and not only reflects the image of the femme-fatal and protagonist (the protagonist typically a man in a suit, and the femme-fatale the alluring woman),  but also the time period as jazz was typical of the 1940s, the era to which film noir is often related to.

The diegetic sounds used in the clip, are to give meaning to the actions. First the footsteps are noticeable, this is often used to create suspense or allows for the audience or characters to be expecting something, in this case it gives the femme-fatale a moment to decide to stay or leave. The second piece of diegetic sound in the lighter, cigarettes are a common theme in film noir, giving characters an air of power or importance. The emphasis on the lighter allows for the cigarettes to hold significance  and for the characters to do the same.

The diegetic sound of the rain starts, and gives the atmosphere a 'deeper' feeling, allowing for the set to seem more real. The rain may also have been emphasised for pathetic fallacy, reflecting the characters feeling the audience can see on screen.