Using a Control Recorder for EVP

Migrated from the Collective

This practice has been moved from the ATransC Collective. The Collective was intended as a community effort to develop Best Practices. After years of failing to attract help from the paranormalist community, it seems reasonable to give up and unilaterally compose these practices.

These practices are recommendations provided under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License


Tom Butler, Cindy Heinen


It is easy to record environmental sounds that are natural, but that sometimes sound like EVP. The problem is finding a way to guard against mistaking ambient or normal sounds as being paranormal. This Best Practice recommends that a second audio recorder be used when the person is unable to assure control of ambient sounds while recording for EVP.

Sound reproduction varies among types and designs of recorders. There are many elements in the design of IC recorders, the type of recorder commonly used for EVP recording, that can cause sound to be poorly recorded and reproduced. To assure that suspected EVP are not just poorly reproduced normal sound, this Best Practice recommends that a backup recorder be used that is able to record and reproduce sound at a superior fidelity to that of the main EVP recorder.


Unnoticed background sounds: The human mind is able to focus on a task at hand, often to the exclusion of unrelated stimuli. For instance, Alva Noë refers provided an example of “inattentional blindness”: “In one study, perceivers are asked to watch a video tape of a basketball game and they are asked to count the number of times one team takes possession of the ball. During the film clip, which lasts a few minutes, a person in a gorilla suit strolls onto the center of the court, turns and faces the audience and does a little jig. The gorilla then slowly walks off the court. The remarkable fact is that perceivers (including this author) do not notice the gorilla. This is an example of what has been called inattentional blindness.”[1]

During the excitement of a hauntings investigation, it is reasonable for an experimenter to not notice background sounds, such as people talking in a nearby room, routine sounds caused by the experimenter or even intakes of breath before speaking. Sounds can be easily mistaken as EVP, not so much because they sound paranormal, but because they were not noticed during the recording session.

EVP and the brain: Memory has been shown to be a three stage process starting with sensory memory, which is the initial recording of sensory information. Some of this information will be encoded into short-term memory where, if not actively processed, it has a limited life of a few seconds. We can, however, further encode this information into long-term memory, but even at this stage memories can be altered or forgotten.[2] During an EVP session our consciousness is focused on the task at hand; conducting the session or doing the investigation. It is not possible to be aware of everything that is going on around us. A backup recorder will provide a hard copy of all the audio that occurs during an EVP session that we are incapable of remembering. Reviewing this audio will assist in helping to verify if a suspected EVP is just a normal voice or sound we do not remember.

Pareidolia is when our brain interprets a vague image or sound as something recognizable or specific. In the case of EVP this would mean finding speech patterns in muted sounds or even random noise. It’s easier to do this than one may think, especially with IC recorder file compression that can alter the tonal quality or timbre of sounds as well as distort normally occurring sounds. A clear, higher sound quality backup recording can be an asset when determining if a suspected class B or C EVP is authentic or possibly just an artifact or distortion of the digital recording process.

Suspected EVP comparison: The fidelity capabilities of recorders should also be taken into account when selecting a backup recorder. The fidelity of a recorder is the quality of the reproduced sound. High fidelity would be reproduced sound that is as close to the original sound as possible. Low fidelity would be sound that is not a true reproduction of the original sound because of distortion, compression or other sound artifacts.

Many of the early IC recorders that investigators used have elements in their design that result in low fidelity voice reproduction due to frequency limitations during recording and sound reproduction, quantization noise, and the limitations of file compression. While proponents of the white noise theory suggest the internal noise produced by these recorders may be just the thing that enables the paranormal voices to be formed on these recorders,[3] it also can drastically change the quality and understandability of normally occurring sounds or voice. This especially holds true to any IC recordings done in a LP (Long Play) or SP (Standard Play) mode. IC recorders can be set to record in a variety of modes that establish recording time and recording quality. Frequency response of the recorders can even be affected by the selection of specific modes. For example, a Panasonic RR-QR160 set to a SP mode has a frequency response of 230 Hz to 3400 Hz, while the response in the HQ (High Quality) mode is 240Hz to 5100 Hz. When recording in SP or LP mode, compression of the audio information gives you more recording time but poorer voice reproduction or fidelity. When researchers record in these lower quality modes it is important to be aware of the sound reproduction capabilities of that particular mode. The use of a backup recorder that reproduces sound at a higher fidelity than the main EVP recorder, especially if this main recorder is an IC recorder set to a lower voice quality mode, is highly suggested.

Simultaneous EVP: The AA-EVP has no reliable evidence that the identical EVP has been simultaneously recorded on more than one device.[4] Sarah Estep has reported that, in group recordings, she has never encountered an instance of duplicated EVP. A typical report: Joan Kachurik August 28, 2005 post in the AA-EVP Idea Exchange:


“I have the very same Panasonic as you just bought, and I also have an Olympus 480PC. I have turned them both on at the same time, spoke into them at the same time, saying the same thing. It is so odd … sometimes I get a reply on the Olympus and nothing on the Panasonic, and other times the Olympus picks up and not the Panasonic. There were a couple of times when both picked up … but said different things. It is really confusing…but at the same time when editing the recordings it is such fun to see what each recorder is going to do.

“The same thing happens with my tape recorders. I have a GE mini cassette recorder, and a GE shoebox tape recorder that I record on at the same time, with excellent results on each one, but always different. I have never received the same EVP at the same time on different recorders.

“Really interesting, isn’t it?”

EVP are not an acoustical event: EVP have been shown to be an electrical event, rather than an acoustical event. The fact that an EVP can be recorded without a microphone,[5] in an acoustically isolated chamber and apparently by only one recorder, makes it reasonable to assume that a sound simultaneously recorded by two devices is not EVP. The sound may be paranormal, as in direct voice,[6] but it is not by definition, EVP.


The procedure recommended in this proposed Best Practice is for EVP experimenters to use at least one audio recorder in addition to the one being used for EVP collection as a control recording device. This may be accomplished by having two recorders in operated by one person, two people working together during recording sessions using their own personal recorders and/or people recording for EVP and other people video recording the session.

The backup recorder should record and reproduce sound at a superior quality to that of the intended EVP recorder.

Video recorders tend to have higher quality audio tracks than are usually found in recorders used for EVP. Most are stereo, giving less likelihood the video recorder will record EVP, but at the same time, giving the ability to have a sense of direction for ambient sound.

It is suggested that the two sound tracks be compared if there is any doubt about the authenticity of an EVP. If the suspected EVP is found on both recordings, then it is the recommendation of this practice to discard that part of the recording unless it contains information that is evidential in some other way. Even then, the possibility that the utterance is direct voice should be considered.

It is also suggested that all suspected EVP be checked against the backup recording.

Example Application

This practice is applicable to any recording situation that has uncontrolled ambient sounds, such as during haunting investigations where sounds from other quarters can sometimes be heard.


  1. Noë, Alva, Perception, action, and nonconceptual content,, Verified 18 December 2007
  2. Myers, David G. Exploring Psychology. New York: Worth Publishing, 2005
  3. Butler, Tom and Lisa. There is No Death and There Are No Dead. Nevada: ATransC Publishing, 2004
  4. Butler, Tom and Lisa, Communication with members and ATransC and other EVP researchers, ATransC Correspondence
  5. Butler, Tom and Lisa, Estep Correspondence, private communication with Sarah Estep
  6. Crawford, W. J., Direct Voice Phenomena,, Verified 18 December 2007


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