Electronic Voice Phenomenon

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[edit] Definition

Electronic Voice Phenomenon, commonly known as EVP, is the recording of errant noises or voice messages to either analog or digital recorders with what appears to be no earthly explanation. Most believers of EVP maintain these are messages from beyond the grave. They point to things such as "missing frequencies" or "frequency shifts" in a spectrum analysis of the recording as proof that no human alive could have spoken these words, or they offer the proof that the recording seems to answer a question asked of the "ghost" being sought. These recordings are made when the recorder is alone, or under what is purported to be "controlled" circumstances. Often ghost hunters will record an EVP as their proof that an area is haunted.

[edit] Origins

In the 1920's an interviewer from Scientific American seems to have started the whole movement inadvertently by asking Thomas Edison if it was possible to contact the dead. Edison had no strong beliefs, but answered as scientifically as possible saying it is not known whether our personalities continue after death, but that if it were true, it may be possible to construct something sensitive enough to pick up our personalities. EVP believers have distorted his seemingly innocuous statement into the urban legend that Edison was working on a machine to do just that. There is no evidence Edison ever did attempt to construct that machine, or that he even took the idea seriously.

Since then the belief has grown, mostly among those who are unfamiliar with how broadcast, recording, and playback technologies work. In America, AAEVP is the largest organized EVP society. Founded by Sarah Estep, AAEVP claims membership in 40 states. Estep not only claimed to have recorded ghosts, but aliens as well. She reported the aliens use other languages and call her "Earth plane Camilla." Currently, AAEVP is run by Tom and Lisa Butler and is now a 503(c)(3) non-profit organization.

[edit] Quotations

"If our personality survives, then it is strictly logical or scientific to assume that it retains memory, intellect, other faculties, and knowledge that we acquire on this Earth. Therefore ... if we can evolve an instrument so delicate as to be affected by our personality as it survives in the next life, such an instrument, when made available, ought to record something."
- Thomas Edison

[edit] Discussion

It is noted by skeptics that cross modulation of radio frequencies produces this very effect. Toasters, coffee makers, guitar effects pedals, tube amplifiers, or any other analog electronics pick up errant AM and FM transmissions combining them in much the same way as a summing amplifier would in a mixing console, through faulty ground loops or poorly engineered components not properly shielded from RF noise. When digital recording media is introduced, problems of poor programming or fragmented memory (RAM) increase the complexity of the recorded errant signal. That EVP believers argue certain frequencies are missing from the recording inherent to human speech, or that those frequencies have shifted, is most likely due to phase cancellation occurring between the combined recorded signals, or errors in the digital conversion of analog signals

Often EVP proponents have pointed to the fact that digital recordings also pick up EVP as proof they are from beyond the grave. What is not noted however is that the actual microphone recording to the digital device is an analog piece of equipment subject to cross modulation in cases of cheap engineering. Poor analog to digital converters, fragmented ram, and faulty programming of lower quality digital devices either compound a cross modulated source, or create new splices of previous recordings added in to the new recordings. Interestingly enough when EVP proponents are explaining how to capture an EVP, often using high quality and properly grounded and shielded equipment is discouraged in favor of cheap and low quality recorders. While it is suggested to use a new tape every time (in the case of tape recordings) the recorders themselves are low quality and often inexpensive units that most likely are not up to the tolerance standards of professional sound engineers. This seems to suggest that EVP proponents may not understand the workings of radio broadcasting and its effect on poorly engineered equipment all that well, and are actually engaging in a controlled misuse of their electronics.

Given that there are billions of radio transmissions filling our airwaves a device that is engineered poorly or has a faulty ground is almost assuredly going to produce strange combinations of human voice recordings that are somewhat mangled and in poor quality. Conversely the very human need to hear what we want to when looking for meaning in things would imply the physics of EVP alone is not to blame. Often ghost hunters and EVP believers want to connect with someone as proof of an afterlife, and may read into whatever recordings are captured something that isn't there.

Even more poignant to the debate of how perception shapes what we hear is the research done by Haskins Laboratories on Sine Wave Synthesis in which Philip Rubin, Robert E. Remez and Jennifer Pardo ask the question "Which acoustic elements are essential for the perception of speech?" The answer they discovered was "None." Their project took core synthesized sinewave tones matching the core tones of an acoustically recorded spoken sentence. In their research it was found that listeners who were asked to identify sinewave signals often reported them as bad electronical music or radio interference. However when asked to transcribe a "strangely-synthesized sentence," listeners readily reported the words of the natural utterances on which the sinewave signals were modeled. The implications of this finding reach beyond simply being able to recognize tones as speech. If natural random cross modulated or fragmented digital recordings happen to match any number of millions of naturally occurring frequencies within human speech, it is likely someone will read the correlating words into something that is not there.

EVP belief was taken one step further by believers at the American Association for Electronic Voice Phenomenon when they began to offer a computer program for download called EVP Maker. This program admittedly uses a random number generator to change an existing .WAV format recording on your computer to add EVP. Of course, that the ghost wasn't talking in the original recording seems to have no meaning to someone that believes a computer program written by a human can produce paranormal effects. (Sometime in 2005 AAEVP removed the referenced website describing how to download and use EVP Maker. The included link is to the archived copy of the site from the Internet Archive.)

In regards to Edison's often (mis)used quote, it seems to be used not only to try and provide legitimacy (Edison was a respected scientist therefore an appeal to his authority is an attempt to bring legitimacy to EVP beliefs) but is completely out of context. Nowhere does he say recording devices themselves are the conduit to the afterlife, he merely states a machine invented to be sensitive enough to ghosts would be able to "record" a response to whatever stimuli this machine is designed to register. At no time was recording media or radio wave transmissions ever touted as proof of afterlife by the inventors or manufacturers of related equipment. In fact, cross modulation and malfunction of equipment was and is well understood by those that invented, manufacture and professionally use radio, television, recording, broadcasting and production equipment.

[edit] Popular Culture

EVP was featured in the movie White Noise(2005) starring Michael Keaton. The quote from Thomas Edison appears before the opening credits.

Television "snow", a phenomenon also associated with a radio receiver, is a common theme in American horror movies, appearing in Poltergeist(1982), The Ring(2002), White Noise, and many others.

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[edit] References

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