O texto a seguir (que peguei em marblehead.net ) faz um bom trabalho ao descrever quem é responsável por quê:
Foley does not cover sounds like car engines, explosions or other mechanical stuff - driving a car around in the studio or blowing up a building is usually not possible although we have tried! We don't do birds, laser blasts, dog barks or rain storms either!
[...]
While a Sound Editor can do very precise and repeatable effects, they have a harder time when it comes to footsteps for example, since every step is different and unique, the pace changes and the mood of the step is always different. With a good pair of shoes and years of practice, a Foley Artist can perform an actors walk perfectly on the first take while making it sound natural!
Quando se trata de quanto dos efeitos sonoros de um filme que são realmente adicionados durante a pós-produção, um trecho de um artigo com uma entrevista ao editor de som premiado com o Oscar Richard King conta que são quase todos eles. No entanto, é mais provável que seja diferente de cena para cena e de filme para filme.
"The audience should believe that everything they hear was recorded the day the movie was shot," says King.
That's far from what actually happens in a feature film. The majority of the sounds that make up a scene has to be recorded and inserted after production by a team of sound designers. The art of recreating sound effects on a stage for a film is known as foley art.