A Basic Overview:
Electronic Voice Phenomenon, or EVP, is the phenomenon of capturing disembodied voices on either audio or video tape, or on a digital recorder. These voices are beyond what the human ear is capable of hearing, however not beyond the capabilities of what a recording device can detect. This is the reason that we can hear them after they have been recorded and upon playback.
Some EVP’s can be heard clearly, while others are more difficult for some listeners. Furthermore, it is thought that individuals hear at slightly different frequency levels and this may be the reason that not all individuals can hear the same thing in a particular recording.
Some EVP may appear to have multiple meanings and/or cannot be heard the same by all individuals. Although the frequency of an EVP may have something to do with this, some feel this is also due to the layering of multiple voices in a given recording.
EVP seems to be created using the vibrations and energy available at the location. The vibrations and energy utilized to create an EVP can be derived from electronic or mechanical noises (not necessarily audible to the human ear) which are emitted by equipment in the general area, batteries and/or other power sources, as well as human energies and vocal vibrations.
A Short History of EVP:
In 1928, Thomas Edison, a pioneer in the field hoped the equipment he worked on would allow him to communication with the dead
In 1959, Friedrich Juergenson, a Swedish artist and film producer, accidently discovered paranormal voices on a recording he had done in the woods in an attempt to record birds.
He continued to experiment for four years before announcing his discovery via a press conference, and then wrote his book Roesterna Fraen Rymden (Voices from the Universe.)
In 1982, Sarah Estep, another pioneer in the field of EVP, founded the American Association of Electronic Voice Phenomena (AA-EVP) to study EVP.Sarah designed a classification system that is still used by most paranormal researchers today. See the side bar to the right for more information.
This link will provide you with a good understanding of the most widely used classification system used by paranormal investigators around the world .
The American Association of Electronic Voice Phenomena website is a site established by Sarah Estep and founded upon her pioneering EVP work. It is a not for profit educational site dedicated to furthering the study of EVP and offers examples, techniques and concepts concerning the phenomena.
It should be mentioned that this site has been changed since the passing of Sarah Estep and integrates TransComminucation into the website.
Some investigators use white noise to help the spirits communicate. Click this link to learn more about this.
There are several programs and methods used in this process. This link will give you some pointers.