While it's certainly not "bizarre" for films to borrow from preexisting movies for their sound design, the source material for some of the noises in "The Evil Dead" is definitely a little left of field.
As Bruce Campbell puts it in his actor's DVD commentary, the ethereal atmospheric noise you hear when the gang ventures down into the cellar, the "light trilling sort of wind," is from a renowned 1949 Orson Welles thriller called "The Third Man," directed by Carol Reed. Not exactly a connection you'd expect, but hey, when it works it works. Speaking of which, the noise that accompanies the roaming entity that bobs and weaves through the woods was made up of "wind, a low drone, a rumble track, and Sam Raimi's voice, which [they] then processed later to make it sort of echoey and distant."
In the film's final moments, when the noises of the cabin encircle Ash, we hear the sound of footsteps on the ceiling. As Campbell describes, the footsteps were actually Sam Raimi "walking around in a recording studio with high heels taped to his feet because his feet were too big to fit in the shoes."
The very faint droning noise that sometimes fills the background has an interesting origin. While Raimi and Campbell were mixing the film back in New York City, "the control panel had a problem with one of the faders," which in turn caused feedback and reverb whenever the volume knob was open. "We could just lay down long sections of this sound because we thought it was a good ambient sound ... [that] didn't cost us a nickel."
