Over the years Gruppo di improvvisazione Nuova Consonanza has been Franco Evangelisti, Ennio Morricone, Egisto Macchi, Mario Bertoncini, Walter Branchi, John Heineman, Roland Kayn, Frederic Rzewski, Giancarlo Schiaffini, Giovanni Piazza, Antonelli Neri, Jesus Villa Rojo, and Battisti D’Amario, among others.
They were a collective of improvisers, founded in 1966, and based primarily in Italy. They are still active in some incarnation today. Gruppo di improvvisazione Nuova Consonanza bridge territories between Jazz, Musique-Concrete, Serialism, and other tenants of avant-garde classical music, with plenty of free-spirited experiment. This is a German documentary about them, made by Theo Gallehr in 1967. It has English subtitles. (Source)