The first role of sound effects is to connect the shots. Sound effects are divided into in-screen and out-of-screen sounds, and in some cases the out-of-screen sounds can lead the protagonist to the next clip, as when we hear the sound of a zombie but there is no zombie in the scene, but when we hear the sound of a zombie we associate it with the scene that follows.

The second function is to impart a sense of reality to the image. For example, if we put a sports car ad without sound next to one with sound, we would have a significantly different sensation about the ad. The use of sound enhances the authenticity of the sports automobile and allows the spectator to better visualise the image.

The third role is to render the atmosphere of the picture, such as in the film Midnight Bell, where a simple ringing of the phone gives people a sense of tension and terror, which can intensify the terrible environment. Sound effects are very significant in horror films, and I believe that sound effects in horror films are more prominent in their purpose of presenting the picture’s atmosphere.

Although many characters are portrayed by their morphological and vocal traits, I believe the fourth duty is to portray the character. However, I believe that sound effects can also be employed, for example, different personalities in the same action, completion of the same action when the sound size, rhythm, and speed are not the same. For example, the same simple action of banging on the door, one person knocking on the door makes a light sound, slow rhythm, and one person emits a loud, fast rhythm, and you can tell he has been knocking really hard. We may determine part of their personality simply by the sounds they make, which is a portrayal of the character. If there were no sound effects, the picture would still be a bit thin and not fleshed out enough for the characters to be portrayed.