Sound Terminology Definitions

Key Sound Terminology

•   Diegetic sound - Sound whose source is visible on the screen or whose source is implied to be present by the action of the film, for example the voice of characters. It is any sound presented as originated from source within the film's world. Diegetic sound can be either on screen or off screen depending on whatever its source is within the frame or outside the frame. 
•   Non-diegetic sound - Sound whose source is neither visible on the screen nor has been implied to be present in the action, for example sound effects of a narrator's commentary. Non-diegetic sound is represented as coming from a source outside story space.
•   Synchronous sound - Synchronous sounds are those sounds which are synchronized or matched with what is viewed. For example if the film portrays a character playing the piano, the sounds of the piano are projected. Synchronous sounds contribute to the realism of film and also help to create a particular atmosphere. For example, the “click” of a door being opened may simply serve to convince the audience that the image portrayed is real and the audience may only subconsciously note the expected sound. However, if the “click” of an opening door is part of an ominous action such as a burglary, the sound mixer may call attention to the “click” with an increase in volume; this helps to engage the audience in a moment of suspense.
•   Asynchronous sound - Asynchronous sound effects are not matched with a visible source of the sound on screen. Such sounds are included so as to provide an appropriate emotional nuance, and they may also add to the realism of the film. For example, a film maker might opt to include the background sound of an ambulance's siren while the foreground sound and image portrays an arguing couple. The asynchronous ambulance siren underscores the psychic injury incurred in the argument; at the same time the noise of the siren adds to the realism of the film by acknowledging the film's (avowed) city setting.
•   Sound effects - Sound effects or audio effects are artificially created or enhanced sounds, or sound processes used to emphasize artistic or other content of films, television shows, live performance, animation, video games, music, or other media. In television production, a sound effect is a sound recorded and presented to make a specific storytelling or creative point without the use of dialogue or music. The term often refers to a process applied to a recording, without necessarily referring to the recording itself. In television production, dialogue, music, and sound effects recordings are treated as separate elements. Dialogue and music recordings are never referred to as sound effects.
•   Sound motif - A sound effect or combination of sound effects that are associated with a particular character, setting, situation or idea through the film. The sound motifs condition the audience emotionally for the intervention, arrival, or actions of a particular character. The sound motifs can be very useful in the rough cut, where they help clarify the narrative functions of the characters and provide a sound association for those characters as we move through the story, for example Darth Vader in Star Wars. The use of sound motifs can help shape a story that requires many characters and many locations and help unify the film and sustain its narrative and thematic development.
•   Sound Bridge - Adding to continuity through sound, by running sound (narration, dialogue or music) from one shot across a cut to another shot to make the action seem uninterrupted.
•   Voice-over - The term voice-over refers to a production technique where a non-diegetic voice is broadcast live or pre-recorded in radio, television, film, theatre and/or presentation. The voice-over may be spoken by someone who also appears on-screen in other segments or it may be performed by a specialist voice actor. Voice-over is also commonly referred to as "off camera" commentary. The term voice-over can also refer to the actual voice actor who performed the recording. The terms voice actor, narrator, voice artist, announcer are all similarly used.
•   Ambient sound - Ambient sound pertains to the pervading atmosphere of a place. (Often more of a psychological, rather than technical description). Ambient sound consists of noises present in the environment. In film and video sound production term Ambience usually means the background sound accompanying a scene. Ambience is used for background sounds, for example, it may have been present in the original production recording (a better term for it is presence) or deliberately added in sound-effects editing in order to provide an acoustic space around the rest of the dialogue and sound effects. An example of this is in Silence of the Lambs, when Agent Starling (Jodie Foster) is down with Lecter in the dungeon, there were animal screams and noises built into the ambience. (One element of the ambience is a guy screaming in pain. The screaming was processed, slowed down and played in reverse).