This interview with Walter Murch may not be new, but it sure is good.
Synchronization of sight and sound, which naturally does not exist in radio, can be the glory or the curse of cinema. A curse, because if overused, a string of images relentlessly chained to literal sound has the tyrannical power to strangle the very things it is trying to represent, stifling the imagination of the audience in the bargain. Yet the accommodating technology of cinema gives us the ability to loosen those chains and to re-associate the film's images with other, carefully-chosen sounds which at first hearing may be "wrong" in the literal sense, but which can offer instead richly descriptive sonic metaphors.
This metaphoric use of sound is one of the most flexible and productive means of opening up a conceptual gap into which the fertile imagination of the audience will reflexively rush, eager (even if unconsciously so) to complete circles that are only suggested, to answer questions that are only half-posed. What each person perceives on screen, then, will have entangled within it fragments of their own personal history, creating that paradoxical state of mass intimacy where—though the audience is being addressed as a whole—each individual feels the film is addressing things known only to him or her.
The cinetrix has a powerful brain crush on Walter Murch.
Want more? Michael Ondaatje's The Conversations is worth seeking out in hardback, as it is as beautifully designed as any of Murch's work.