Electronic voice phenomena (EVP) are recordings of voice or voice-like sounds that are not audible to the human ear. The frequencies of these sounds are reportedly well below the range of sounds that can be perceived by the human ear. Typically, but not always, they are short having a length of only one word or a short phrase.
In the 1920s, Thomas Edison told a reporter from the Scientific American magazine that he was working on a machine that would give the ability to contact the dead.
Electronic Voice Phenomenon - Voices From Beyond the Veil
Ever since the invention of electronic recording devices people have found strange voices appearing on their recordings, sometimes speaking directly to them, even though no one was present but themselves. The Electronic Voice Phenomena or EVP has been raising controversy as to what it is they are capturing on tape. Could it be the voices of souls who have "passed on" and wish to speak to loved ones left behind or is it an elaborate hoax meant to deceive the gullible?
A great deal of study has gone into EVP since the 1920's. Even Thomas Edison, when interviewed, stated "it is possible to construct an apparatus which will be so delicate that if there are personalities in another existence ... this apparatus will at least give them a better opportunity to express themselves". That first device was the electronic recording.
Skeptics claim that all people are hearing in electronic voice phenomenon recordings is random noise filtered through the desire to hear something; called "pareidolia" (a psychological phenomenon involving a vague and random stimulus, often an image or sound, being mistakenly perceived as recognizable). Or, they claim, all they are recording is the bleed-over from radio transmitters. The research has shown time and again that the skeptics have NOT studied electronic voice phenomenon in any depth at all.
Those who wish to find out the source of these mysterious voices on their tape recordings, none of which are heard until the tape is replayed, have gone to great lengths to eliminate these obvious possibilities. They have recorded voices in heavily shielded rooms specifically designed to prevent radio wave penetration. Another experiment that has been repeated often and with great success is in asking specific questions while recording and leaving a silence between them in case there is an answer. Quite often when they play back the recording, they find that some one or something, has responded directly to the question asked, often naming the querant personally. The odds of this being random radio interference has been calculated as being so high that winning the lottery would be an everyday occurrence by comparison.
Quite a bit of study has gone into figuring out how these voices manifest. Since we create sounds on the physical plane by passing air through our throat and mouth to create the sound frequencies our ears can perceive, it has been tested to determine how a non-physical entity can produce the frequencies on tape that we can hear. More and more it is shown that the reason the EVP researchers don't hear the voices directly is because whatever is causing the sounds are having to manipulate existing sound frequencies at the point in the machine where the processing of the analog sound to a digital format for storage is taking place.
Therefore, a place which is kept quite silent will produce little or no electronic voice phenomena whereas in an environment with a full range of "white noise" very good results are usually achieved. It has been shown that a common house fan is even better for this than an electronically produced "white noise" generator. While old style tape recorders have motor hum and the tape "hiss" which is not the best background for creating manipulative sound frequencies, they are much better than state of the art recorders that have been designed to create little or no sound.
Much of the controversy surrounding Electronic Voice Phenomena comes from the purveyors of organized religions. The possibility that there truly is an existence of personality beyond death (despite their stated beliefs in a "heaven" or "hell") seems to disturb them greatly. They propound that if investigators are hearing anything at all it must be "demons" doing the talking. EVP investigators has shown that overwhelmingly, their recordings show such an abundance of love, compassion and concern for the living that if what they are hearing IS demons, then the religious debunkers might want to reexamine their definition!
Whatever it is that causes these voice imprints onto electronic media, be they ghosts, spirits, aliens (or even demons), the fact is that EVP's are real and that continued research and experimentation will eventually determine all the "How" of the occurrences and be able to refine the process till communication between out physical mortal realm and whatever non-physical place they come from will become a fully realized scientific fact.