Some of you may have been wondering about the XMic research project that has shown up at a couple of the ghost hunts over the last year or so. This research project is designed to look into the possible origin of EVP’s from electromagnetic (EM) fields hitting the microphone and converting into an audio signal. How is this possible? By an electromagnetism principle known as Faraday’s Law which shows that you can create a voltage in a wire by exposing it to a changing magnetic field. This is exactly how a microphone works. In a microphone, a small diaphragm, usually a thin sheet of plastic, is attached to a movable coil of wire around a magnet. When the diaphragm is vibrated by a sound wave, this vibration moves the coil though the magnetic field of the magnet and generates a voltage in the coil with the same size and frequency of the sound wave, thus creating the electric signal that is recorded in the audio file.
For the hypothesis being tested by the XMic, we are theorizing that EVP’s arise from an independent magnetic field of unknown origin. In this case, this anomalous field, which has the frequency content and variation of a vocal signal, hits the coil in the microphone and, since it is a varying magnetic field all of its own, does not need any motion of the coil to generate voltage in the coil that appears in the audio file as a voice. In this case, neither the diaphragm nor the magnet of the microphone are needed to generate a recorded voice. The XMic then, is designed to remove these active parts of the microphone, leaving just the coil. This means that any voices recorded by the disabled microphone cannot be caused by actual sound waves and must be electromagnetic in origin. The original XMic was exactly this, a microphone with the diaphragm disabled.
Unfortunately, the disabling of the diaphragm also caused other issues within the microphone that were difficult to resolve and still keep the microphone electronics intact. In the newest version of the XMic, we instead replaced the whole diaphragm/coil/magnet assembly with just a larger coil wired into the microphone electronics. To test the functioning of the XMic, we used Faraday’s Law in the reverse mode to generate a known magnetic field next to the XMic In this case, we hooked a coil up to the headphone jack of a laptop and played a known sound file into the coil. This voltage within the coil from the playing of the audio file will generate a silent magnetic field with the same frequency content as the audio file that should hit the XMic coil, be converted back into a voltage, and be recorded as an audio signal.
With the set-up shown in the figure below, that is exactly what we were able to do. In addition, the same magnetic field was shown to inject the known audio signal onto an unaltered microphone and, to a lesser extent, onto the recorder itself with no active microphone. If our EVP hypothesis is correct, with the new XMic in hand, recording an unaltered microphone and the XMic on two channels of the same recorder should allow us to record EVP’s isolated from the any sound waves being recorded and will go a long way to proving that EVP’s are an electromagnetic phenomenon and not an audio phenomenon.