Electronic voice phenomena came to light in 1959 when the Swedish filmmaker Friedrich Juergenson unwittingly captured voices on audiotape. After recording birdsong in a forest, Juergenson discovered on playback that there was a distinct male voice remarking about birdsong at night! Listening carefully, Juergenson also heard the voice of his deceased Mother! After his discovery, Juergenson went on to record hundreds of 'spirit voices' for the following four years and consequently published a book in Swedish in 1964 called "Voices From The Universe", this book was followed by another called "Radio Contact With The Dead".
Since the late 50's, many people have recorded voices on audiotape and now digital media and the obtaining of EVP samples has become common practice in the activities of those investigating paranormal activity.
White Noise - This is broadband random noise signal which has not been filtered (sounds like equipment background hiss). This has the same energy per Hz frequency. Although white noise can be used as a multi-frequency test source, pink noise is more useful in sound system analysis.
Pink Noise - This is a broadband random noise signal which has been filtered using a 3dB per octave low pass filter to provide equal energy per octave (sounds like bass-heavy hiss). The reason for using pink noise is that it better matches the way the human ear hears sound. Pink noise is used to analyse the effect of speaker response and room acoustics.
On a typical RTA graph, pink noise feeding a 'perfect' sound system would result in a flat line response.
We at East Anglian Paranormal are using an EVP recorder which has both white and pink noise recording options available to us.
