Wednesday, January 21, 2009
Sound is very simply a physical vibration (acoustic energy) transmitted by either a gas, liquid or solid. Sound is characterized by the properties of sound waves, which are defined by frequency, wavelength, period, amplitude and speed. Although the human ear is capable of detecting sound between 20Hz and 20,000Hz, the ear is most sensitive to sound waves that register between 1000Hz and 3,500Hz. Most human speech occupies a range between 200Hz and 8000Hz. So if EVP is truly "speech" as we currently understand it, isn't it logical to assume that EVP should occur only in that narrow frequency range?