Sound and musical score can be vital to a movie's atmosphere and its effort on the audience. Think about it. Would the Wizard of Oz have been complete without the cheerful, colorful music? No, it would have appeared that Dorothy was being attacked by a band of psychotic midgets and not being praised for killing the wicked witch of the East if the musical score were not in place.
Since the dawn of the cinematic age, music and special effects have been instigated in giving the audience a heightened awareness of the happenings on screen. Even in the 1900s, the classic black and white, silent films had sound effects and a musical score of some sort. The famous silent film A Trip to the Moon was accompanied by a pianist, who made the fake cheesy moon transform from a mere puppet to a frightening alien intent on destroying the space ship.
Radio has used sound effects and musical score as well to draw the listener into the program. Orson Welles frightened the entire nation with his adaptation of Invasion from Mars, by Jules Verne. The sound effects were simple items that managed to scare some of the most (and least) intelligent people in the country.
These same simple sound tricks worked for some literary classics brought to the screen. Henry James's 1898 The Turn of the Screw was made into the terrifying 1961 film The Innocents, directed by James Clayton. The sound effects used in this movie added to the atmosphere and the eeriness of the work as a whole.
The opening credits of The Innocents introduces the audience to a young girl's voice singing gaily of a weeping willow tree. The song is peasant and almost makes the onlooker want to hum right along with the soothing rhythm. The audience quickly learns that this sweet singer is Flora, played by Pamela Franklin, the young girl that Miss Giddens, played by Deborah Kerr, has been charged to care for.
The child's song, though pretty at first, takes on an almost devilish tone as the movie unfolds. And spirits of the dead begin popping up. Miss Giddens' terror for the children is mirrored on the audience's faces when they learn that Flora had learned the truth from her former and now-dead teacher, Miss Jessel, played by Clytie Jessop. It makes one want to cut down the weeping willow and use it for firewood.
The song transforms Flora into a scary creature, who talks to ghosts and may even be possessed by one herself. When the credits roll, and Miles, played by Martin Stephens has died from a heart attack, the song plays again; but the tone has turned from scary to depressing. It is amazing how many tones a song can have.
Another element employed in the movie is the use of echoes to try to convince the onlooker of Miss Giddens' impending insanity. The children's voices are layered on top of each other to give the impression of a thousand children laughing and saying a thousand different things.
The lack of sound in the movie in parts was as equally frightening as some of the loudest effects used. For example, when a very ghostly Peter Quint, played by Peter Wyngarde, is perched on a statue staring meaningfully down upon Miss Giddens and Miles, he opens his mouth and laughs; but no sound escapes his lips. That is more frightening than the most evil Hollywood villain can possibly laugh.
If I had a thousand children screaming in my brain, one slightly disturbing girl singing a song a dead woman who is having me standing next to me, and a ghost not laughing at me on a stance, I think I would go crazy too.