The Insub Meta orchestra (IMO) is a large ensemble gathered around the experimental and electroacoustic practice.It was founded in 2010 by the Cyril Bondi and d’incise duo. It consists of about fifty permanent members that form the thirty international musicians present at each concert. Born from questionings on improvisation in a large group, the IMO built with time a strong collective and typical background where the individual gesture get lost in the production of global sonic states. Thus subtle matters emerge and interact with silence. The notions of improvisation or composition become confused in a constant research of a specific development in the context of this orchestra. Its axes are the place of silence, an electroacoustic and extensive listening, the work on durations, the mimetism, low volumes, non-hiérarchical relations, the circulation of informations.