Synchromy

“What you see is what you hear. In this 1971 masterpiece, McLaren achieved what much of the audiovisual art world has been trying for decades: a perfect symbiosis of image and sound. McLaren, who had been making experiments in electronic music for a long time by painting soundtracks directly on the film, made a radical move with Synchromy: colored pattern cards representing the optical composition were placed both on the sound and picture areas of the film, so that the spectator literally visualizes music or musicalizes vision.”

http://thesoundofeye.blogspot.com.au/