Posted by
Peter Needham on
URL: https://www.es-forum.com/digital-voice-recorders-tp1538504p1538514.html
"My husband got a little digital voice recorder for $40. It has a
varying magnetic field while playing back, that varies with the loudness of the
sound. When someone on the playback laughs loudly, the magnetic field goes up
to 10 or 15 mG. (I could not check it while recording as it is full and my
DH is too busy to deal with it presently.)"
yes - this is simply because the speaker that makes the sound is
pushed backwards and forwards by a varying DC current, to produce the
sounds, similar to a standard phone, and its how loudspeaker
technology works generally, but as its a fairly inconsistant pattern
of frequencies (unless you play the same music/voice all the time)
then there are probably less damaging effects, if any.. the
frequencies are also not all that high or low, 20hz to 20khz on a good
hifi system..
Cheers
Pete
On Sun, 27 Mar 2005 12:49:07 EST,
[hidden email] <
[hidden email]> wrote:
>
>
> Kattrina asksed about digital voice recorders.
> My husband got a little digital voice recorder for $40. It has a
> varying magnetic field while playing back, that varies with the loudness of the
> sound. When someone on the playback laughs loudly, the magnetic field goes up
> to 10 or 15 mG. (I could not check it while recording as it is full and my
> DH is too busy to deal with it presently.)
> Generally speaking, battery-operated gizmos are safe for ES people. I
> have heard of a few cases of people sensitive to the batteries themselves.
> Meaning, a battery just sitting there, not being used. Presume they must be
> sensitive to the magnetic field, as I don't know what else it could be.
> (Marc seems to be sensitive to the slight magnetic field produced by the
> GS filters. Marc, are you sensitive to batteries?)
> Some battery-operated gizmos do create RF, of course, and these are not
> safe. A battery-operated flourescent bulb lantern creates its own RF as this
> is how fleurescsents operate. I turned on on in a room with a radio on once
> and the radio just screamed. I had never heard such a noise from a radio!
>
> I use a solar-charged LED lantern with no problems at all. I love it.
> It is bright enough to read by.
> A battery-operated electric shaver or toothbrush will avoid the RF that
> one would be exposed to if using a plugged-in unit. There will be a strong
> magnetic field, though. I used to use a battery-operated rotary tooth brush,
> but quit because it had a strong m field indeed and I just didn't know what
> effect that might have on my living body.
> At any rate, a battery-operated recorder will prevent the RF exposure
> you'd get with a plugged-in recorder. Also, the magnetic field drops off
> shasrply just inches away from the recorder. So setting it down rather than
> holding it or having it around your neck should deal with the magnetic field
> exposure. Just test the unit before you buy it to be sure you get good sound when
> the person speaking is the distance away at which you would use the recorder.
> Regards,
> Shivani
>
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