So far, most of the EVPs people have collected are in frequencies that humans can hear. The thing that puzzles me is that usually we don’t hear the sounds during the actually recording of the EVPs. It’s after scrubbing through the recorded audio we stumble upon it. This wouldn’t bother me so much if these recorded anomalies were in a frequency range humans can’t hear naturally but in most cases it is.
Throughout the history of paranormal investigation the technology has changed with no impact on capturing EVPs. We have gone from analog recording of EVPs to digital and people are still successful in capturing them. So I have some questions now. How are these sounds captured with out us hearing them during the recording session? Is there possibly more sounds but in frequencies humans cannot hear?
To start, I look into how we capture these EVPs. I thought we could start with the actual device the sounds are captured on. Sounds recorders. These are devices that have a microphone and some type of media to embed the sounds to. i.e. magnetic tapes or digital disks. So how does a recorder actually do it thing?
The microphone is a type of transducer. In other words it converts one type of energy to another type of energy. In our case it converts sound waves (Acoustic energy) into an audio signal (Electrical energy). The main device that helps convert the sound waves is the diaphragm within the microphone. When sound waves hits the diaphragm it makes it vibrate along with other components. This movement is then turned into an electrical current, the audio signal.
With this knowledge of how we capture audio and with the EVP examples my first thought was "Why don't we actually hear the actual sounds during recording?". When I look at the EVPs spectral waveform I can see that the EVP is at frequencies that we should be able to hear naturally. So why don't we hear them on location? Maybe the EVP isn't actually a sound wave? Maybe it's some type of other energy that the microphone can pick up?