This paper is the second part of Avant-propos du langage des objets au langage des choses, deux mots sur la révolution baylienne: first part, third part.
Through examples of François Bayle's works, the author defines the notion of metaphor in acousmatic music. This notion closely follows the concepts of the sound object and morphologie or phenomena. The two revolutions in Bayle's theory are to create music from plastic objects (in opposition to Schaeffer's theory) and to forget the notion of reduced listening.