Buster Keaton on the MGM sound stage used for Speak Easily (1932) (via)
Paul Newman, Robert Redford, & director George Roy Hill on the set of Butch Cassidy and the Sundance Kid (1969) (via)
Franco Bixio, Fabio Frizzi, & Vince Tempera - Seven Notes: Pt. 1 (Seven Notes in Black: Original Motion Picture Soundtrack)
The score was performed on a carillon (tuned bells sounded by hammers controlled by a keyboard), accompanied by strings, low synth, and piano tones.