Ã stor PantaleÃ n Piazzolla ( March 11 , 1921 â `` July 4 , 1992 ) was an Argentine tango composer and bandoneÃ n player . Astor PantaleÃ n Piazzolla ( March 11 , 1921 â `` July 4 , 1992 ) was an Argentine tango composer and bandoneÃ n player .