I saw this on Coudal and thought it looked familiar--I'm as much of a Murch groupie as anyone, really--then I realized I'd posted about it last year on Daddy Types. [You know how it goes, come for the womb mentions, stay for the editing tips.]
Anyway, Walter Murch did an online companion piece to his lecture, "Dense Clarity - Clear Density," complete with sound and video clips, for Transom.org. There's also an essay called "Womb Tone," in which he talks about the in utero development of hearing and the shocking discovery a newborn baby makes upon leaving the womb: silence.
Always fascinating, that guy Murch.
The Transom Review: Walter Murch [transom.org]