I recently watched The Innocents (1961), directed by Jack Clayton. It was to my surprise that a few days later, I found out that the sound effects were created by Daphne Oram, whose work on the film was uncredited.
I remember while watching the film that I was very impressed with the sound, something that is often lacking in older films. The reverberant sounds certainly brought the film to life, as well as creating surreal moments of tension that were much more effective than the orchestral elements of the score.
Oram was a pioneering composer and musician known for her work in founding the BBC Radiophonic Workshop (1958) as well as for her development of Oramics, a method of sound synthesis using drawn sound, where 35mm film was drawn upon and transformed into sounds.
She created the music for the play Amphitryon 38 (1957) using a sine wave oscillator, a tape recorder and filters, making the first wholly electronic score in BBC history.