EVP or Electronic Voice Phenomena is a term used to describe the reported discovery of voices or other attempts at communication unintentionally captured in otherwise normal audio recordings or recordings intentionally sought in radio static or ambient recorded background noise.
Usually audio recordings need to be filtered and manipulated to separate put the suggested EVP or extra-sensitive or specially prepared recording equipment needs to be used.
It has long been thought that paranormal events could be registered using recording equipment. The great spiritualist movement at the end of the nineteenth century coincided with the discovery and use of radio and audio devices. Thomas Edison himself theorised about the kind of audio equipment that might be needed to communicate with the dead.
It has been pointed out, however, that the amount of preparation and interpretation that EMP commonly require means that almost any meaning could be ascribed to the recordings in question and that equipment itself can ioften produce noises that can be heard as human voices.
Most often the phenomena are ascribed to a kind of pareidolia – the natural human tendency to find patterns in random events and, more particularly, the way that people tend to see human faces and hear voices in otherwise innocuous images or sounds.