Diegetic sound
Diegetic sound in Casablanca is evident when Ilsa asks Sam to play the song ‘As Time Goes By’. The fact that the characters themselves can hear the music is important to understand how Rick cant bear to listen to the song that reminds him of Ilsa, and just hearing it causes him to dart across the room to stop the music and halt the pain he feels in remembering his past.
Diegetic sound also is significant in ensuring the verisimilitude of the film, in the midst of war and occupations elsewhere, residents of Casablanca come to Ricks bar to listen to music and forget the troubles of the world around them.
Non-Diegetic sound
The use of underscoring in Casablanca is also non-diegetic, in the first scene between rick and Ilsa they recall the last day they met. The score starts as a soft romantic violin, to represent how Ilsa is first ignorant to the torment that happened that day, and only remembers the love she felt for Rick. Synchronising with Ilsa’s change of expression, she then recalls how the Nazis occupied France that day, the underscoring then turns dramatic and violent.
This is used to share the heartbreak that Ilsa feels with the spectator, to immerse them in the movie and to feel as though they themselves experienced the same things.
Sound Motif
The use of sound motif in Casablanca holds a highly emotional response in the spectator. The first time the audience hears the song ‘As Time Goes By’, Ilsa doesn’t even need to say the name of the song as it is so ‘forbidden’ that Sam isn’t allowed to play it. This foreshadows an importance regarding the song, thus leaving the spectator to imagine the meaning behind the pain this song causes Rick, and the connection Rick has to Ilsa.
Connoting this song to pain, the spectator is then reintroduced to ‘As Time Goes By’ when Rick is alone, drinking, and feeling sorry for himself. The Mise-en-scene paired with the diegetic sound motive that is ‘As Time Goes By’ evokes a moving response in the viewer that is then justified by Ricks flashback of the last meeting between Rick and Ilsa in Paris, the day the Nazis came. A Romantic and beautiful song is reduced to a painful, heart aching experience, likewise of the relationship between the Ilsa and Rick.
Dialogue
Rick’s famous line: ‘Here’s looking at you kid’ is an example of Dialogue in Casablanca, the way he repeats this line throughout the movie connects the plot, and gives the spectator an idea of the relationship between the two.
Synchronous sound/ atmos and foley sound
Synchronous sound, or sync sound, is audio that lines up precisely with what’s happening on screen.
An example of this is the clink of Ricks glass as he slams it on the table in this sequence, similarly Foley/atmos sound is used to accentuate the sound of a door slam when Ilsa leaves Rick once more. This is made to be louder, more prominent as the pair are once again separated and Rick is left alone like in Paris. This heightens the dramatic effect of this scene, and evokes a isolated feel in the spectator.