Krause has a word for the pristine acoustics of nature: biophony. It's what the world sounds like in the absence of humans. But in 40 percent of the locations where Krause has recorded over the past 40 years, human-generated noise has infiltrated the wilderness. "It's getting harder and harder to find places that aren't contaminated," he says.
From a filmmaking standpoint, it's becoming nearly impossible to find an area completely devoid of background noise. For Car Trouble 2: Them's the Brakes, the first project I ever did audio post for, the director and I drove four hours in every direction over two days to try to get some clean background tracks (or atmos, for those of you across the pond) and came up empty handed. Ultimately, we ended up looping nearly every line, and creating the remaining sounds from scratch using library tracks, recorded years ago when you actually stood a chance at getting a clear recording.
Please to enjoy (bear in mind, that in addition to being my first post outing, that it was also mixed in Final Cut Pro 3, a blunt tool for audio):
Link to Wired article.