cacophonous effect in his Paris studio, c. 1970 Occupation(s) Composer, architect Years active 1947–1997 Giannis Klearchou Xenakis (also known as Yannis or Iannis Xenakis; Greek: Γιάννης "Ιωάννης" Κλέαρχου Ξενάκης, pronounced [ˈʝanis kseˈnacis]; 29 May 1922 –