How to avoid getting 'EVP'

Originally posted on Monday, June 01, 2009



How to avoid getting 'EVP'

Yes, I said it- How to avoid getting "EVP", or in this case, Electronic Voice Pareidolia. I can’t begin to tell you how many false positives I have heard over the years. Everything from footsteps, a car driving by in the distance, a dog barking, an air conditioner cutting on, and even investigators whispering or talking in another room are all examples of things I have come across. There are ways to avoid all of these and they are simple. I’m not going to go off on a long tangent regarding protocol. You should know that well before you start in this field. If not, that is on you. I will however discuss equipment.

Most investigators use “Digital Voice Recorders”; while these are nice and handy, many just do not cut it for so-called “scientific” data collection. I have said it before and I’ll say it again --- Most “DVRs” are just simply too lo-fi. Many record to sub-par standards in order to allow for more storage. This degrades the quality to the point that a burp will sound like a demonic entity from outer space rather than a belch from an investigator. Unless your “DVR” records to at least CD quality (16 bit/44.1kps) then it is not cut out for data collection. Many of these voice recorders also record straight to MP3 rather than an uncompressed wav or raw format. MP3 is a compressed file format. In order to make a file smaller it cuts out commonly unused frequencies --- Or, frequencies commonly unused in music. This presents a problem because it limits your, what audio engineer’s commonly refer to as, “head room”. This, along with the AGC, will take away space in the audio and cause a crunching leaf to sound like a spooky voice saying “yes”. Some researchers also believe that these frequencies which are cut out during compression are where anomalies tend to occur. So you don’t want to limit yourself by limiting your frequency range. Same thing goes for the microphones you use. Always find the widest frequency range microphone you can find. If you are doing RTC with headphone's, find the broadest frequency responsive headphones you can find.

Another problem with “DVRs” is the previously mentioned AGC or Automatic Gain Control. This is a built in circuit that is in place to increase the loudness of the quieter sounds. It works much like an audio compressor but only increases the level when it detects a sound below a certain decibel level. This will cause distant voices to seem ghostly when they are simply someone speaking aloud in another room. Really all of these issues contribute to the problem to certain degrees.

So to put it simply, you want a digital recorder that records to wav or raw data formats at 16 bit/44.1kps or above. Not many, if any, “DVRs” have these specifications. There are alternatives, however. Rather than using a Digital Voice Recorder, look for a Digital Field Recorder. These are either aimed at creating music or broadcasting and the like. They are higher fidelity and overall better quality. I know that many paranormal investigators are using the Zoom H2 now and that is a great unit. It records up to 24 bit/96kps and records to wav or MP3. It also has the ability to turn off the AGC, along with many other nice features. I use this unit and have been thoroughly enjoying it. For example; I recently received a couple possible anomalies to review that came from a “DVR” that records to MP3 at 16 bit/32kps and uses an AGC. I was able to listen to the same spot on the audio data from the H2 and realized what seemed like a ghostly “hello” was simply someone readjusting their position and rustling some covers on a bed. So high fidelity is the way to go. I cannot tell you how many false positives are simply pareidolia. There are plenty of other Digital Field Recorders on the market ranging from $100 to $1500.

This isn’t to say that your old trusty “DVR” is not useful. You can still use it for recording personal notes or even client interviews. I personally am working on something to use my old “DVR” as a data collection device for different light spectrum's --- more on that when I get it built and working.

If you can’t, or don’t want to, dish out the money for a field recorder then there is another, albeit cheaper, option- Old school cassette tape. Even though tape does have its slight frequency limitations, and can create hiss, it is uncompressed. Sometimes cassette recorders do have an AGC circuit so you have to be careful about that. On top of all this, some researchers in the past have claimed that anomalies may show up better on magnetic tape. In fact in the earlier years of EVP research this is what was believed to cause the anomalies. As far as I know this research was never completed. People simply picked up the next handy techno gadget and ran with it.

With cassette tape you must use an external microphone to avoid recording the gears of the tape machine. This, however, is a plus because often times the external microphone you buy will have a broader frequency range than the built in microphone. You can normally buy a nice cassette recorder for $20-$50 and a nice external microphone for $15-$35. So for $40 you can have a nice tape set up. Additionally, cassette tape is dirt cheap nowadays. I once came across a red tagged deal of 50 tapes for $15.

So overall, you want to know your equipment and how it performs. You want to know its specifications and limitations. If we want the hardened skeptics to ever think twice, we are going to have to bone up on the way things are done. Offering up a pile of Electronic Voice Pareidolia is simply not cutting it and frankly, it makes the paranormal field look like a bunch of mush brained jackasses.