EVPs and Frequency

 I was recently asked if EVP’s are recorded at a certain frequency and how can I be sure if my recorder can record in that frequency range? So I started to research this and have ended up with more questions than answers. The biggest hurdle is how to answer a question that has not been scientifically proven to exist or not.

 I have been reading many articles and opinions on how EVP’s are formed and captured and we will start with the assumption that they are voices that fall into a certain frequency range… most of the time. The majority of articles and other paranormal groups claim that EVP’s captured at 300Hz and below are considered to be “true EVP’s”. To understand why this is we need to look at the frequency range of the human voice and hearing. When it comes to the human’s ability to hear we are able to detect sound in the frequency range of 20Hz to 20,000Hz, However our ability to speak falls in the frequency range of 300Hz to 3500Hz. Now there are some very talented individuals who can produce sound much lower than 300Hz. But that is just sounds or noise with no discernable speech pattern. Intelligible speech stops at 300Hz. So if humans cannot produce understandable words below 300Hz, then voices recorded at frequencies below 300Hz must be some type of phenomena.

After downloading and analyzing 25 to 30 EVP recordings I got some very interesting results. When choosing EVP’s to analyze I tried to find some that were listed as being less than 300 Hz, I only found one listing. After analyzing all of the samples I downloaded they were all above 300 Hz except for one. Most of them fell into the 300- Hz and above including the one that was listed as being at 141 Hz. What surprised me was one by the same group that had no mention of the frequency it was caught at was around the 200 Hz mark and it was a class A evp. This was well below the 300 Hz range of the human voice. Now all of the other samples that were in the higher range are still considered EVP’s but not “True EVP’s” because there is no way to prove that it was not someone in their group or a passerby etc.

So now we know that we want a recorder that can capture 20 Hz to 20,000 Hz, the frequency range that humans can hear. Most recorders will do that as long as you are on the correct settings. You will also want to check the bitrate it is recording at. Your bitrate needs to be double the highest frequency you want to record. For example if you want to record up to 44,000 Hz then the bitrate would need to be 88,000 Hz or 88 KHz.

So how do these voices get onto our recordings and why at different frequencies? There are a few theories on this subject and the most common one is that the spirits or entities are manipulating the background noise on the recording to form speech. In this theory it would make sense that the EVP would be in the same frequency as the background noise. Before Digital recordings, back when we had to use magnetic tape it was thought these voices were imprinted onto the magnetic tape by the energy of the spirit. Digital recordings do not have magnetic tape so how does that work? This is where we get the theory of manipulation of background noise. Researching this I found another theory, and to me it provides a lot of answers to many of the questions left unanswered in both of the theories. So let’s Dive in.

 This part of my report is from a paranormal scientist with The New England Center for Paranormal Research named Michael J. Baker.  Wanting to know how EVP’s were created onto different formats such as reel to reel, cassette tape, and now digital recorders, what is the common thread that would explain voices that are not heard at the time being captured on our recordings. The one thing that has not changed much over time in the way it works is the microphone. There are three types of microphones used in recorders, dynamic, condenser, and electret condenser. For a natural energy source he uses electro-magnetic energy. Electro-magnetic waves travel in the same frequency as our voice but are undetectable by the human ear.  The results were amazing and followed a lot of traditional patterns associated with EVP’s. Here are some examples.

The Dynamic mic was louder than the electret condenser as in the older reel to reel and cassettes seemed to pick up on more EVP’s than the digital.

The energy source had to be within a foot for the microphones to capture these energy waves on the recording device. This may be why we will get a voice on one recorder and not the second one sitting close by.

For every energy wave produced there was a small electromagnetic field increase produced. Could this mean that detected EMF spikes are missed EVP’s?

To read Michael J. Baker’s article on this experiment you can follow this link. http://www.ipaawards.org/profiles/blogs/the-science-of-evps-revealed

Now we know that when we choose our new audio recording device that we want one that can record in the frequency range of 20 Hz to 20,000 Hz, the range the human can detects sound. Anything above or below this range we would not hear it when listening back. We also know that if it’s possible we want to use a dynamic microphone for the best chance on capturing EVP’s. So make sure you check out the manufacturers specifications on a device before purchasing. Once you by a new piece of equipment study how it operates and what settings are going to give you the best results before using it on an investigation.


John B

MGH Trainee


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