EMF and spontaneous sound
I am a paranormal researcher. I hope someone can help me understand sound, particularly how EMFs might affect recordings.
Allow me to backtrack a bit. Paranormal researchers often record electronic voice phenomena as part of the research we do. EVPs are generally voices that have no known point of origin. Sometimes they appear to be interactive (answering questions) and sometimes they are noises such as telephone ringing.
The general consensus, with paranormal researchers, is that these sounds have a "paranormal" origin, if they can not be proven to be from another source.
Researchers have collected these sounds on many different media types, including tape, but at the moment most researchers use small digital voice recorders.
I have always taken these sounds for granted as being true voice without known source.
But lately I have been reading about researchers getting better results (more EVP) by using devices to amplify the electromagnetic field in the area.
I got curious as to how EMF affects sound and if amping the EMFS could produce false positives voices on the recordings.
Can someone help me understand this?
Hello Suzette and welcome to the Cow Audio Forum.
Microphones used in video production are of two types, mostly; dynamic and condenser.
Dynamic mics are based on the principle of a moveable diaphragm attached to a coil of wire. The coil is suspended in a magnetic field. A sound causes fluctuations cycles of rarification and compaction in the air. Those differences hit the diaphragm. The diaphragm moves. When it does, the coil attached to it moves in the magnetic field. This creates a voltage in the coil wires that becomes the audio. As long as the coil moves in the magnetic field, a voltage is generated.
A condenser microphone uses the principle of charged metallic plates; one fixed, the other is a moveable membrane. Sound causes the movable membrane to come closer to and then farther away from the fixed plate. This variation in proximity generates a voltage that becomes the audio.
Thus, microphones at their simplest, measure the movement of air molecules and/or the rarifaction and compression of sound waves. Without air motion, conventionally designed microphones probably make poor detectors.
However, if you remove the grounded metallic head grille from most microphones, they become quite the antennae, picking up all sorts of local electrical "noise" emanating from light fixtures, power lines, computers, radios, and you name it. Were you able to create an oasis in which typical, man-made emf generators did not exist, unshielded mic capsules might be able to "hear" other electrical variations.
EVPs, I suspect, sometimes may be communicated telepathically to one or many people. Designing a receiver for that would prove challenging as they may not move air molecules the way sound does.
Ask the most devout believers and I'm sure you'll find they hear spoken syllables where others do not.
On the other hand, having spent a number of years using CB radio, my friends were frequently amazed at how I could understand what people were saying in "all that noise."
When you amplify sound captured with any microphone, there are limitations. First is the selfnoise of each microphone. That's the noise made by the mic's own circuitry. The Neumann TLM 103 has one of the lowest selfnoise figures 7 dB-A. It is also a very sensitive mic. You would stand a better chance of capturing audio which could then be amplified with this mic than others. Perhaps operating one of them with a partial or modified headgrille might give you something new.
EMF noises not audible in air can also enter the audio circuity, usually after the microphone diaphragm, and become demodulated into the audible audio range by accidental processes of the particular circuit. The mics and preamp, then, are working more as receivers of very high frequency energy. Energy that is well above the range of human hearing. Waves below the frequency and volume thresholds of human hearing can be recorded with good microphones. Speeding playback up, or slowing the high frequency disturbances down so they become audible is possible.
Hope this helps.
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