Electronic voice phenomena (EVP) are electronically generated noises that resemble speech, but are not the result of intentional voice recordings or renderings. Common sources of EVP include static, stray radio transmissions, and background noise. Some have claimed these sounds are of paranormal origin, while there are natural explanations such as apophenia (finding significance in insignificant phenomena), auditory pareidolia(interpreting random sounds as voices in their own language), equipment artefacts, or simple hoaxes. Recordings of EVP are often created from background sound by increasing the gain (i.e. sensitivity) of the recording equipment.
Parapsychologist Konstantin Raudive, who popularized the idea, described EVP as typically brief, usually the length of a word or short phrase.
The concept of the paranormal first began to attract a great deal of interest in the early 1800s, with the rise of Spiritualism. Spiritualists believed that they could communicate with “the other side” through people known as mediums, and a large cottage industry of mediums arose in the 19th century to feed popular demand. Spiritualists also described paranormal experiences, ranging from abductions to hauntings, and Spiritualism later grew into parapsychology, which purports to be a scientific study of paranormal activities.
One early researcher on EVP, Konstantin Raudive, worked on the issue in the 1960s, publishing several landmark works in the field. Some people refer to EVP as “Raudive voices,” in a reference to this pioneer. Raudive believed that EVP communications were generally short, often just a word or phrase, and he suggested that they were communications from the dead.
There are a number of ways to record EVP, and proponents of a paranormal explanation for EVP often use multiple recorders and other techniques in an attempt to make their recordings as test-proof as possible. Some people simply record white noise, listening for signs of EVP, while others claim to have identified EVP in recordings of speeches, songs, and so forth. EVP also allegedly comes through on the radio waves, and in the static between television stations.
EVP researchers say that the highly interactive communication they have engaged in would be impossible to discount as interference or brain tricks. "I have been an amateur radio operator for 40 years, and I have never had tape or digital recorders pick up any artificial interference," says one researcher. "Also, how can an interactive EVP, where the spirit is responding to my questions or commenting on my words, ever be considered interference?"