Are there qualitative tools specifically adapted to the analysis of the sound environment and what is their operational value? Since the seventies, several tools of reasoned description were proposed like the “sound object” or the “soundscape”. Theoretically fundamental, these instruments remain partially unsuited to the scale and pragmatic imperatives of architectural and urban design. The “sound effect” can be reduced neither to an exclusively objective data, nor to a subjective data. It is more precisely the product of an encounter, of a correspondence, of an interaction between the physical, “objective” soundscape, the soundscape of a cultural community and that specific to each individual. Susceptible of precise description either from the acoustic point of view, or from the point of view of the built environment, or from the point of view of the psychosociology of listening, the sound effect can first of all serve to decompartmentalize the fields of knowledge on the sound and the sound practices. It can also be particularly useful as an aid to measurement, as a descriptor of complex sound situations, as a tool of representation, of intervention or as a pedagogical tool. A repertory has been elaborated, it crosses the descriptions and the analyses of more than eighty sound effects and specifying their correlations, is a major contribution to the elaboration of a true instrumentarium adapted to the Listening of the environment. Bibliographic Reference – Jean-François Augoyard, Henry Torgue (dir.) A l’écoute de l’environnement : répertoire des effets sonores. Parenthèses, 174 p., 1995. – Jean-François Augoyard, Henry Torgue (dir.) Repertorio degli effetti sonori, Lucca : Libreria Musicale Italiana, 192 p., 2003. – Jean-François Augoyard, Henry Torgue (dir.) Sonic experience, a guide to everyday sounds. McGill-Queen’s University Press, 216 p., 2006.