Robert Bresson once said in an interview: “We must let the mystery remain. Life is mysterious, and we must see that on screen. The effects of things must always be shown before their causes, like in real life.”
Sound for Tarkovsky is a mysterious force. A device to help express different plains of reality - the inner caverns of the mind, the material world, nature and the spiritual plain. In film as in life it moves in mysterious ways. Like a gas, sound diffuses in and out of our field of vision, within and beyond the frame of the camera. In doing so it leads us to question the nature of our reality, of our very existence: Where are we? What force is at work here? Sound itself is both that of a physical body and of spirit. Something of this and of another world. Andrea Truppin in her inspiring essay And Then There Was Sound: The Films of Andrei Tarkovsky (1992) talks about "sound's potential for ambiguity and abstraction" and how this is deployed by the director to evoke the existence of unseen objects and to penetrate into the invisible spiritual world. Truppin writes: "Allowing a sound source to remain a figment of our imagination, mystifying rather than orienting, subverts sound's traditional role in film."
Excerpt from Booms, Bells and Distant Voices - The Ambiguity of Sound, 2014, Rob Szeliga