hmmmmmmm....I can actually answer your question Crystal, our group is a major work in progress and I'm the only one who really puts any of my own funds into our equipment so far. When we did our first investigation we were using two different tape recorders, and yes they were tape recorders, not digital because I got them for free and didn't have much funding into the equipment yet, The sound you are hearing is actually the humming sound that the internal mechanisms of the recorder makes. If I happened to be using an external mic at the time, which we didn't have either, you actually wouldn't hear it. So you just may be right about the audio being amplified too much.The only problem I see with this hypothesis is that the overwhelming majority of of the members of my group are actually skeptics so they try to rule absolutely everything out that they can through a scientific, realistic standpoint. after reviewing the files we all tried to recreate the file in every way that we could im order to prove it was not a real evp with no success. We went back to the site, stood in different spots different distances away from each other, muffled our voices, changed the tones of our voices, ran the recorder on slow while recording, recorded with both devices at the same time, , recorded over a previously used audio file on a tape even recreated the conversation we were having while taping the segment, and tried a couple other things as well. None of it worked. You seem to have alot of knowledge in the field so I definitely highly respect your take on the subject, and maybe you will have more luck with it than us, I will take your theory back to my teammates and see what they think of it and in the meantime, if you come up with anything more, feel free to let me know, I'm open to all suggestions because we are really at a standstill here, again thanks alot, I hope to hear from you soon