I'm by no means an audio engineer--not even close--but I know my way around audio files, and I've spent the past few days listening to the Catherine EVP, hoping that something would jump out at me. My gut impression is that the recording is a valid EVP, primarily because if someone wanted to fake an EVP, he could have done a better job of it. The recording is very primitive and downright strange. Its strange tonal quality reminds me of the EVP presented by Brendan Cook and Barbara McBeath of the Ghost Investigator's Society. Genuine EVP sound slightly mechanical--almost computer-generated. If you've ever heard speech converted to audio by a cheap transcription program, you know what I mean. And I do get hear that "mechanical" timbre in this file.
Not having to software to analyze the file, I did something that I often did to audio files when I was a teen--I listened to the file slowed down to approximately half speed. A couple of things stand out. First, the music: I don't recognize it. It would be interesting if anyone could identify it. (It would also be significant if it *couldn't* be identified.). It almost sounds like music captured by an external microphone from a low-fi source, like a radio. Such a "recording of a recording" adds a slight but recognizable layer of noise that audiophiles can pick out; but I can't hear it here, which is a bit unsettling. Slowed down, the music practically disappears and I hear instead a loud and oscillating vibrational monotone.
At the three-second mark there is a very noticeable artifact that sounds like an externally generated "bump," like the sound of someone jarring a table while recording with an external mic. At half-speed, however, this artifact is noticeably louder and sounds more like a "break," electronic in quality, like the electrical noise created when microphone is plugged to a recorder while recording.
The voice of a woman (Oh, Catherine") intrudes at the last second and is cut off in mid-word. Slowed down to half speed, however, I notice something interesting. The "oh" is at normal pitch even at half speed, and the pitch drops rapidly during the "Catherine" portion. So the speaker starts at a very high pitch (above the audible range) and rapidly modulates downward in pitch. This rapid drop in pitch would be difficult to produce in a natural recording.
I'm not saying that all this "proves" that the recording is an EVP, or that this is even distinctive. But having been a careful listener all my life (going to far as to run my turntable backwards to incontrovertibly hear "Paul is dead" on the White Album), I think it's interesting.