Orson Welles was master craftsman and he believed that if the sound is going to be right then the movie is going to look right. It is a well-known fact that he developed the concept of deep focus photography he complimented it will the use of deep focus sound. This meant focusing on each sound intently and deeply. Orson Welles did that by regulation the sound level in such a way the depth of the image of the sound appeared to sound deeper than that of the real image. It was like the sound was also doing acting, acting their part. Let us take for example the Colorado scene where the sled is gradually getting covered by snow and the intensity of the snow is getting increased by the sound of the train whistle which is increasing gradually. The sound of this whistle is so subtle that many miss it in the beginning