What are Electronic Voice Phenomena (EVP)?

Electronic Voice Phenomena / Audio Voice Phenomena

Electronic voice phenomena (EVP) are sounds found on electronic recordings which resemble speech, but are reportedly not the result of intentional recording or rendering.

EVP are commonly found in recordings with static, stray radio transmissions, and background noise. Recordings of EVP are often produced by increasing the gain (i.e. sensitivity) of the recording equipment.

According to the American Association of Electronic Voice Phenomena (www.aaevp.com), “EVP are anomalous, intelligible speech produced in electronic devices. They may be heard as a real-time output but are more generally heard on review of a subsequent recording. No currently understood physical processes account for the existence of EVP.””

They typically constitute short utterances of just a few words, often in direct response to questions or comments about occurrences in the environment.

Interest in EVP surrounds claims that they are of paranormal origin, although a number of natural explanations have been offered including apophenia (finding significance in insignificant phenomena), auditory pareidolia (interpreting random sounds as voices in one’s own language), equipment artifacts, and hoaxes.

Some EVPs are more easily heard and understood than others. They can be either male or female, of any age, tone and emotion. They usually speak in single-words, phrases and short sentences. Sometimes they are just grunts, groans, growling and other vocal noises.

EVPs have been recorded speaking in various languages. The quality of EVP also varies. Some are difficult to distinguish and are open to interpretation as to what they are saying. Others are quite clear and easy to understand. EVP often has an electronic or mechanical character to it; sometimes it is natural sounding.

Psychology and Perception

Auditory pareidolia is a situation created when the brain incorrectly interprets random patterns as being familiar patterns.In the case of EVP it could result in an observer interpreting random noise on an audio recording as being the familiar sound of a human voice. The propensity for an apparent voice heard in white noise recordings to be in a language understood well by those researching it, rather than in an unfamiliar language, has been cited as evidence of this, and a broad class of phenomena referred to by author Joe Banks as Rorschach Audio has been described as a global explanation for all manifestations of EVP.

The human brain evolved to recognize patterns, and if a person listens to enough noise the brain will detect words, even when there is no intelligent source for them. Expectation also plays an important part in making people believe they are hearing voices in random noise.

Apophenia is related to, but distinct from pareidolia. Apophenia is defined as “the spontaneous finding of connections or meaning in things which are random, unconnected or meaningless”, and has been put forward as a possible explanation

Radio and Human Frequency Vs. EVP

Usable voice frequency band ranges from approximately 300 Hz to 3400 Hz.

The accepted frequencies for human hearing are 20Hz – 30,000Hz. EVP’s are based on frequency and some EVP’s are recorded at below300 Hertz with some going down to 70Hz range. Some EVP’s are recorded above 34,000 Hz range also.

A typical adult male will have a Fundamental frequency from 85 to 180 Hz. A typical adult female from 165 to 255 Hz but most speech falls below the bottom of the “voice frequency” band.

Grading of Evp’s

There are 2 thoughts on the grading system of evps. The most common formed of grading is the Raudive class system that breaks it down to 3 classes.

Class A

Easily understood by almost anyone with little or no dispute. These are also usually the loudest EVPs

Class B

Usually characterized by warping of the voice in certain syllables. Lower in volume or more distant sounding than Class A. Class B is the most common type of EVP.

Class C

Characterized by excessive warping. They are the lowest in volume (often whispering) and are the hardest to understand.

Class R

EVP has a reverse meaning.

Each group will added other classes to this list but in general most groups will agree on this system. The other thought is that this class is not needed and should be only audible and non audible.

How to conduct an EVP session.

· note the weather, start and end times, location of the room and where in the room the recorder is being placed and people that are present in the room/location.

· Set up at least 2 recorders at the location. Let the 2nd one record non stop during the session.

· Setup EMF meters and any other measuring devices near the recorder. Also set up a video camera to record the session.

· At the start of each session, wait 10 seconds before asking any questions.

· Wait 10 seconds between questions.

· Ask simple but relevant questions

· Try to record in short segments, 3 – 5 minutes at a time is fine. Any longer and it will be very hard to listen on play back.

· Document all questions and all noise at the time the session is being done.


· If you have to talk during the session please talk in a normal voice and say your name.


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