Do you mean DVR’s or DAR’s? Video or audio recorders?

First, I am not comparing or suggesting, just relating what I am doing.

I have conducted experiments/testing with a mic less recorder. As I have with placing a recorder in something and I know of someone who conducted the Bell Jar experiment. I understand yours is a preliminary experiment and you won’t necessarily have the problems I did.

I found with my preliminary fact finding experiments/testing (to establish baseline results before the actual ones) that I had a problem with placing audio recorders into cans, boxes, jars and anything else I could shove one onto thinking I was creating a soundless environment for the recorder. In each case I found that the container itself, being a solid as some of the other sound proofing items I thought would work, were actually great conductors of sound and that different outside sounds relating to the conductivity of the container were being picked up by the recorder with the mic.

I have to admit and take into account that my experiments won’t be the same as yours. I am trying to keep things as simple as I can too. I don’t want to over complicate things and I am not an electronics expert either. Which is ok for me as I am not interested in anything besides physical sound. I also didn’t do my experiments/testing in a cemetery or abandoned building that should be very quiet to begin with. I began my experiments/testing in and around my own home with known noises so I would have baseline results for comparison.

So far the best thing I found for my experiments will be one of my camera cases lined with acoustical treatment foam, which is relatively inexpensive and designed to reduce or eliminate sound as best as it can. Remembering that for me, I only want to block out physical sound and nothing else since my theory relates to recordings being picked up directly by a recorder. So far nothing has compared to the camera case for me.

Now that I have baseline information for comparison I am taking my experiment to Gettysburg, Pa. this Sept. where I found a place that I can normally get class ‘A’ EVP’s or what I perceive as possible voices fairly regularly. We go every year so I have already ruled out many possibilities for the possible voices. This will be my first official disabled mic recorder experiment. I am kind of excited as I consider what I have done so far as just testing.

I am looking forward to your future posts.

It's not that crazy when you consider that the magnetron inside it is putting out enough energy to literally melt your brain in the time it takes you to read Dilbert in the morning paper. That's an insane amount of power to be shielding with anything smaller than a bank vault, so for as light as it is, the shielding is pretty effective in my book. You are right that there are usually a few small leaks though, which is why I don't stick my face in the window to watch the turntable spin. My eyes are bad enough as it is without boiling the ocular fluid in them.

Even grounding can create noise in analog signal paths, if you accidentally get two ground references that aren't at the same relative potential. Yet another of the many reasons I love digital signal transmission so much.

I can't remember what I was getting at ~1 foot, but it was pretty high, so I suppose it'd have been around 13 dBm. I find it ironic how high up a microwave sits and how many guys stand just right in front of it! But yeah, your eyes are usually the first thing to hurt if you are starting to get cooked, but if you believe that RF may cause cancer, then its something to consider.

And you are right. If you have bad grounding on an analog line, you'll have noise. But this is a digital recorder with the mic disconnected right? The mic, if it were the quartz crystal or similar type would be your biggest sensitivity issue. Unless I'm missing something, which is very possible!

I know you already tackled this problem, unless I missed something, but fly screen (copper screen) attached to a ground will do the same thing. It's how we used to isolate commercial radio transmitters from errant RF.