Sound

SHUTTER ISLAND

http://www.imdb.com/video/imdb/vi3240494105/

All the sounds in this scene are there to reinforce Teddy Daniel's dilusional and confused mind set. It highlights everything as he sees it through his fantasy. Because of this, some sounds are much louder or more emphasized than they would normally be and at first this confuses the audience because they cannot understand what they are hearing or that it is actually his subconsious's version of the action. However, if you watch the film again you understand how everything fits together to form his warped view of the world.

Non Diegetic Sound:

• the background music is very prominent. It builds up and up as if to something very tense, however the action doesn't ever match it. This initially gives the impression that it is simply a bad soundtrack, but once you get to the end of the film, you understand why it was so loud and misleading. 
• The music is exaggerated to mirror his confusion of reality. He feels that something is building up but cannot understand what it is or why, so the music reflects his growing sense of urgency. 
• The sound motif that you hear is repeated several times throughout the film however, despite it's suspense, it is only played when during moments that are not meant to be tense at all. During the actual tense moments, it is completely silent, therefore increasing the suspense much more effectively.

Diegetic:

• The script itself is very disjointed, for instance when Deputy Wardon McPherson says 'I've never seen a marshall's badge before' it seems out of place and unnecessary. The second you see this you understand that again, this adds to the confusion in Teddy Daniel's mind. But it also shows how apprehensive everybody else is in this unusual situation.
• The only ambient sounds in this scene are the click of the marshall badge, the noise of the guns, the footfalls and right at the start the bird song and the sea. The moment they move away from the water's edge, the noises of the birds fades to silence and the noise of the sea fades. However, the water that you can actually hear does not match what you should be able to hear, it is more like the noise of water in a lake which links to the past that Teddy Daniels has blocked out of his memory. The click of the badge is highlighted to bring the audiences attention to the fact that he is of a high position of authority in this scenario. 
• The voices are only males which shows that it is a very male dominated area and they reference positions of authority and speak formally to one another which suggests that this is a work environment that is to be taken seriously. 

SHERLOCK

Non Diegetic Sound:

• The music only starts when Sherlock enters the room, bringing importance to this event and emphasizes the shock as the audience realise what he is planning on doing. It increases when Watson enters the room and then again when he reveals the bomb. This shows the change in atmosphere as Sherlock and the audience realise that the tables have turned. 
• The music stops completely when Sherlock says 'Stop it' which increases his authority in the situation.
• It starts up again very quietly when Moriarty is introduced to the scene to build suspense and hold the audiences attention.
• Also, while the script bounces between Moriarty and Holmes in a mocking manner, the music brings a sinister edge to the scene which reminds the audience that this is a serious situation.

Diegetic Sound:

• At first the noise of the water is very quiet, this suggests that it is not of any importance. However, the moment Moriarty enters the room, it increases in volume to represent Sherlock's heightened senses as his body fills with adrenaline.
• Sherlock's footsteps are very loud when he enters to bring awareness to the fact that he is all alone. He speaks in a mocking, patronising manner which gives him authority and suggests that he has the upper hand. Once Watson enters and the situation becomes clear to him, his voice becomes unsure and quiet, this shows his emotional attachment to John and also tells the audience how scared he is.
• The noise of the door when John enters the room and when Moriarty enters the room is very loud in comparison to the other ambient noises to highlight the other person coming into the room.
• John speaks in a very monotone voice which tells us that he is very scared. This manner coupled with the fact that he talks about himself in the third person tells us that he is repeating what is being said to him. 
• Moriarty's voice echoes more than the others' which adds authority to it. He also speaks in a mocking, assured manner which suggests to the audience that he now has the upper hand. 
• For the first half of Moriarty's dialogue, the script is very one sided which shows how unsure the other two are.
• However, when Sherlock cocks his gun, he becomes much more confident and starts to play with Moriarty it seems. This coupled with the loud noise of the gun suggests that he has a plan. At this moment, the noise of the gun represents a spark of hope. 

In this clip, all of the non diegetic sound is designed to build the tension and all of the diegetic sound is designed to show who has the authority in the situation.

This shows us how sound can be used to create different atmospheres and how it can help the audience understand what is happening.