EVP: Science, theory and explanations.

Electronic Voice Phenomena:

An examination of the history of electronic voice phenomena related to the study of paranormal events, its methods, alternate explanations, analysis and documentation and how to collect and document EVP correctly.

by: Anthony Justus





“…If our personality survives, then it is strictly logical or scientific to assume that it retains memory, intellect, other faculties, and knowledge that we acquire on this Earth. Therefore…if we can evolve an instrument so delicate as to be affected by our personality as it survives in the next life, such an instrument, when made available, ought to record something.”

–Thomas Alva Edison, inventor.


On October 18th, 1931, Thomas Edison, inventor of the modern electric light-bulb lay in his bed, dying. He looked to his physician and said, “It’s very beautiful over there.” As a scientist, Thomas Edison was not a man that tolerated nonsense or pointless ideas. It is said by some that he must have believed in what he experienced on his deathbed,  otherwise, he would not have reported it or commented on it as such. At the moment of his death, the ornate library clock in Edison’s study stopped cold as did several assistant’s clocks, at 3:24 AM. No explanation to this day has ever been made as to why all the clocks stopped as they did, though his sons did try to find out who stopped them, however no one ever admitted to committing the act.

Edison himself theorized in response to an interview question that should our spirit survive physical death, that an instrument that was sensitive enough to such energies should be able to detect it or interact with that part of us that has moved on beyond the body and make a recording. There is no evidence that Edison himself ever attempted to create such a device, despite claims to the contrary. Has that moment now came at last, some eighty-years after Edison’s death, that we, at last, may have a machine that allows us to reach across the barrier between life and death and contact those who have passed on before? Some say that yes, indeed we have. What is the machine? What possible intricate and exotic device could this be?

The audio recorder.

The goal of this paper is to examine several things including the history of EVP, what EVP is believed to be, alternate explanations for EVP, and equipment used to capture EVP as well as analyze it.

History of EVP.

Thirty years before Edison’s now famous quote in 1901, American ethnologist Waldemar Bogoras had made an expedition to Siberia to study the shaman of the Tchouktchi tribe. In a dimly lit room, he witnessed what the shaman claimed was a spirit summoning ritual. The shaman beat a drum rhythmically, increasing in volume with every beat, the pace increasing exponentially as the shaman himself seemed to fall into a trance like state. Bogoras was shocked to hear the room suddenly fill with voices from which he could not pinpoint a source, speaking a garbled mix of English and Russian. “I set up my equipment so I could record without light,” Bogoras wrote, speaking of his phonograph (Macy, 2010). The shaman himself, Bogoras noted, sat twenty feet away and “when the light was extinguished the spirits appeared after some hesitation and following the wishes the of the shaman, spoke into the horn of the phonograph.” When he played the recording back, Bogoras was amazed to find that he could hear the shaman talking as well as the ceaseless drumbeats…and the voices of the spirits talking over the shaman. Coupled with the drumbeats and the shaman talking, the voices sounded like they were right on top of the phonograph input, which ruled out the shaman as he was over twenty feet away and never moved.

It was the first time in history that spirit voices were reportedly captured on a recording device, resulting in the world’s first EVP. But it would not be the last, not by far.

In 1910, a Catholic altar boy in Brazil often saw his superior, a priest, Roberto Landell do Moura, speaking into a small box which then would speak back. Father Moura did not share the details about what was in the box or how it worked as official Church rules frowned on any type of communication with spirits (May, 2010).  In 1925, Brazilian researcher Oscar d’Argonell wrote the book, Voices from Beyond by Telephone, which recorded details of his long telephone dialogues with supposed spirit friends.  In 1936, American photographer Attila Von Szalay began to experiment with a record cutter and had some success in capturing spirit voices on phonograph records, similar to Bogoras in 1901.  He partnered with Raymond Bayless, a writer, and found stronger success in using a wire recorder and both men published the results of their experiments in an article for the American Society for Psychical Research in 1959 but neither ever received further attention nor was their article considered a success.

Perhaps the two most important incidents in the history of electronic voice phenomenon occurred in the early and late 1950s. In the early part of that decade, in Italy, two Catholic priests, Father Ernetti and Father Gemelli were collaborating on music research. Ernetti was an internationally respected scientist, a physicist and philosopher as well as an avid music lover. Gemelli was President of the Papal Academy. On September 15, 1952, while the men were recording a Gregorian chant, a wire on their magnetophone kept snapping. Aggravated and tired of fooling with it, Father Gemelli looked up and asked his father, who was deceased for help. To the shock of both men, the voice of Gemelli’s dead father recorded on the magnetophone answered: “ Of course I will help you. I am always with you.”

Stunned, the priests repeated the experiment and again, got a response, this time the voice of Gemelli’s father seemed to find it funny that they had such a hard time believing it was him, commenting discarnately from the recorder, “ But Zucchini, it is clear don’t you know who it is I?”

Zucchini had been Gemelli’s nickname that his father had often teased him with when he was alive. While deeply touched and grateful to be able to speak to his long departed father, the event troubled the priests who wondered if they had any right to speak with the dead. The two men visited the pope, Pope Pius XII, in Rome and told him of their experiences.

The Pope simply dismissed any wrong doing upon their behalf and said “ Dear Father Gemelli, you really need not worry about this. The existence of this voice is strictly a scientific fact and has nothing whatsoever to do with spiritism. The recorder is totally objective. It receives and records only sound waves from where ever they come. This experiment may perhaps become the cornerstone for a building for scientific studies which will strengthen people’s faith in a hereafter.”

While reassured, Gemelli did not publish his findings or the record of the incident until near the end of his life in 1990.

At the end of that decade in 1959, Swedish film producer Friedrich Juergenson captured voices on audiotape while taping birdsongs. When he played the tape back, he heard a male voice say something about “bird voices in the night”. Upon closer inspection, he also heard his mother’s voice say, in German, ” Friedrich, werden Sie aufgepaßt. Friedel, mein kleines Friedel, können Sie mich hören?” Translated roughly, this means “ Friedrich, you are being watched. Friedel, my little Friedel, can you hear me?”

Now convinced that he had made an important discovery, over the course of the next four years, Juergenson continued to record hundreds of claimed paranormal voices and playing the tapes are international press conferences and in 1964, published a book in Swedish, Voices from the Universe and later, another work, titled Radio Contact with the Dead.

The development of what was perceived to be research on EVP continued through the years, and attracted now household names to it, at least in the paranormal community, such as Konstantin Raudive, Latvian psychologist skeptic turned believer who began to study EVP after visiting and learning the methods of Juergenson, with Raudive himself recording many hours (over 72,000 voices) of communication with the dead. In 1971, Raudive was tested independently by Pye Records who initiated a controlled experiment in which Raudive was not allowed to touch or interact with any of the equipment used to record for 18 minutes. The room in which Raudive was placed was shielded against stray radio or television broadcasts. During the recording session, only Raudive himself was heard. Upon playback however, over 200 separate voices were discovered.

It was in late 1973 that most EVP researchers consider a major breakthrough in communicating with the dead was achieved. Paranormal researchers George and Jeanette Meek met a supposedly very psychic man named William O’Neil, who reportedly, could see and hear spirits. O’Neil was also a gifted man with electronics and according to most sources, combined his knowledge of electronics and his gifts of mediumship to produce a new device and method of communication called the SpiriCom. SpiriCom was set of tone generators and frequency generators that emitted 13 tones spanning the range of the adult male voice. Apparently and according to O’Neil, he received help in his design for this device by working together with deceased physicist Dr. George Jeffries Mueller, who’s ghost is said to have materialized to O’Neil one night in his living room. BY 1980, the SpiriCom device had advanced to the point that the disembodied voices were very clear, though strangely buzz filled.

Some would accuse O’Neil of faking the voices with an electric larynx, though this was never proven based upon the buzz-filled sound of the recordings, the fact that neither Mueller’s nor O’Neil’s voices ever overlapped and the fact that despite detailed plans, diagrams and other SpiriCom’s being built, no one was ever able to replicate the type of results O’Neil did. (May, 2010).

In 1982, Sarah Estep founded the American Association of Electronic Voice Phenomenon, AAEVP, which was an organization devoted to the study and research of EVP recordings and even developed a classification system for the EVP recordings based upon their clarity, Class A (recordings that needed no cleaning, no filtering and were absolutely clear to the listener, a very rare type), Class B (which are loud and garbled and are agreed upon to be a voice but what the voice is saying is unknown) and Class C (vocalizations or sounds that are not voices yet should not be present on the recording). Some go further, by adding a Class D, which is any audio event not covered by the previous three categories. (Macy, 2010).

In more recent times other devices, spiritual successors the SpiriCom have been developed to reportedly allow real time communication with the dead, such as Frank’s Box in 2002,  of which Frank Sumption, the box’s creator, claims the design came from the other side, much like the SpiriCom. Frank’s Box supposedly worked as a combination white noise generator and an AM radio receiver modified to sweep back and forth through the AM band, selecting split second snippets of sound. This box was heavily criticized, perhaps rightfully so, due to the extremely subjective nature of the sounds it produced and since it relied upon radio noise, any response the user may get is either coincidence or a result of audio pareidolia.

The Ovilus and the Paranormal Puck were devices that were also made within the last ten years designed reportedly to contact the dead by utilizing sensor input in the form of electromagnetic readings, temperature shifts and changes in the atmospheric conditions of an area to produce words either from pre-selected dictionaries or voice synthesizers. The reliability and viability of these devices is hotly debated and open to interpretation as none has been proven to work.

So, with all this history, what is EVP?

EVP is an acronym that stands for electronic voice phenomenon, and refers specifically to a form of supposed communication from the dead, in which a speaker asks questions to empty air and records the session and upon playback, voices which were not heard during the initial recording are often heard respond to the speaker in the most common set up. This set up, while common, is by far not the only method of conducting EVP research and EVP is one of many variations of what has been termed “instrumental trans-communication” or ITC which refers to the use of technology by the dead to reach out to the living or vice versa.

EVP is commonly believed by most paranormal investigators to be the voices of the dead or in rare situations with other forms of ITC, the actual manifestation of the visual and audio aspects of a personality that has been deceased. One of the most perplexing aspects of EVP is why it is so often unheard during the recording. Some research teams and ideas as to why we cannot hear EVP at the time it is recorded is that it may be a type of psychokinetic influence on the circuits in the digital audio recorder or perhaps a psychokinetic  (PK) imprint on magnetically sensitive tapes (standard cassettes). While EVP may in fact be a PK event, the theory remains unproven as of this writing. If it is in fact a PK event, it remains to be seen if the recorder (person who is actually recording the session) is the one who is the agent for the PK influence or if it a discarnate intelligence which is using PK to manifest itself on the medium, which is the device itself.  PK testing conducted at Duke University suggests that PK does in fact have a stronger affect on random number generators or computers for all intents and purposes. A digital audio recorder is nothing more than a very simple computer however this does not adequately explain why EVPs are caught on magnetic tape.

Josh Warren’s investigation team in North Carolina, LEMUR, have done experiments that show that the reason why an audio recorder may pick a sound up but your ears may not is that your ears are designed to pick up sound waves not electromagnetic signals. Sound waves are air vibrations that cause the ear drum to vibrate whereas something like say a radio signal is an electromagnetic wave. Our hearing system is not designed to “translate” electromagnetic signals into proper sound but a microphone is.

Most decent audio recorders are actually shielded against radio frequency feedback to prevent the accidental pick up of radio frequencies but what LEMUR found out was that if you take an audio recorder and wire a radio or sound output device to broadcast its sound not with sound waves (air vibrations) but rather as a projected energy wave (electromagnetic wave) that the recorder’s microphone will still pick up the sound and re-interpret it as sound even though we can’t hear the broadcast at all.  This suggests the possibility that the reason we cannot hear EVPs in real time is that whatever is causing them, ghost or otherwise, may in fact be using an electromagnetic wave to transmit sound as opposed to air vibrations. Whether or not this electromagnetic wave is influenced by PK remains to be seen, however, given the success rates of experiments such as Helmut Schmidt, who was one of the major pioneers in using random number and random event generators, in particular ones that used strontium-90 as the basis for random generation, and given the fact that PK does seem to be able to manipulate electronics, the idea that a PK influence on a magnetic field existing is not far fetched (Parapsychology Handbook, 1977).  The experiment by Warren that support the theory that EVP is a magnetic field thus why we cannot hear them is described in its entirety below from Josh Warren himself:

Understanding EVP
A Practical Demonstration

How is EVP activity recorded?

Electronic Voice Phenomena, or EVP, is a general term for ghostly sounds that are captured using audio recording devices. Traditionally, EVP refers to spectral voices, as the original term implies. However, that term has come to be used in connection with paranormal audio that does not necessarily include a perceived voice, or voices. EVP are most often sound effects, like footsteps in an empty room, or strange knocks and bangs. But, of course, voices are what most paranormal researchers strive to capture most. These voices can be interactive, answering questions presented by investigators or communicating information about the research environment.


EVP is most notable because it is not heard by the naked human ears. The recording is made in a place that appears to be quiet. However, when the recording is played back, the ghostly audio is heard. Sometimes an audio recording device is left to record by itself in an apparently quiet environment. Other times, an investigator will ask questions in a place that seems to be soundless, while recording the session and pausing after each question in anticipation of an answer. Then, when the recording is played back, answers will indeed follow the questions.

Humans can hear from around 20-20,000 hertz. If the recording device is sensitive to lower or higher frequencies, it could explain why sounds are captured that humans cannot perceive. However, the devices that capture EVP are usually sensitive to the same range as human hearing. This is perplexing to most people, since it doesn’t seem to make sense that the recorder would document a sound that was not audible at the time. However, it is relatively easy to explain why this may occur.

For years, investigators speculated that spirits might directly imprint electromagnetically-sensitive audio tape. Indeed, this may sometimes be the case. However, the advent of the digital recorder changed that perception some, considering digital recorders use no tape, but are still capable of capturing EVP. Instead, it seems most likely that ghosts produce electromagnetic oscillations that are not perceived by human ears, but can be easily interpreted by a microphone. In fact, the type of microphone used may be the greatest factor in determining the quality and range of EVP a recorder can capture. This can be easily demonstrated with a relatively simple setup.

If you take a radio tuned to a station, and plug a large coil of wire into the headphone jack (where sound comes out), you will hear nothing. This is because the coil of wire does not act like a speaker. It only takes the electrical signal from the radio and broadcasts it from the coil. When you turn the volume on the radio all the way up, you still will not hear anything, but the electrical signal traveling through the coil is strong. Next, take an audio recorder, with an external microphone, hold it near the coil, and record. When you play the recording back, you will find the radio station has been recorded loud and clear. Sound was transferred electromagnetically from the coil to the microphone, and the microphone interpreted the electrical signal as sound to imprint on the recording medium. At no point were the sound waves resonating air (like a speaker), and the resonance of air is essential for such sounds to be perceived by ears.


Considering ghostly activity is so prominently connected to electromagnetism, it seems that spirits may communicate by producing electrical signals that are easily perceived by the microphone, but not the investigators present. Of course, if the investigators are monitoring the room live via microphones, then real-time audio communication may be possible.


If you conduct the radio experiment, you can test out different types of microphones, and microphone positions, to determine the best techniques for recording EVP. Just remember to turn up the radio volume all the way and use an external microphone for best results. At many electronics stores, you can find a headset jack that is split into two wires. Simply hook each end of your coil to each of these wires, and plug the jack in securely. The larger your coil, the stronger your broadcast will be.”  (Warren, 2010).


What about possible alternate explanations for EVP?

            There are a large number of alternate explanations for EVP and these must always be considered when conducting EVP research and eliminated as possibilities. Some of these include radio interference (remember LEMUR’s experiment that was able to produce EVP like effects with an electromagnetically transmitted sound) , electric interference (such as electric current that is not grounded properly), psychological effects such as audio pareidolia, meteor showers  affecting broadcast waves and of course, simple fraud or even apophenia.

Pareidolia and apophenia are the two most often cited caused for most EVP recordings as most EVP recordings out there on the Internet and being publically viewed are Class B or below, thus greatly reducing their effectiveness as evidence for proof of anything and a general lack of knowledge on behalf of the teams who present such weak recordings. Pareidolia is the human mind’s tendency to find familiarity in visual or audible “noise”, similar to seeing familiar shapes in clouds. In the case of EVP, some scientists suggest that the voices are nothing but artifacts created by the subjective processes of the mind trying to make sense of the random noise (Psychology, 2009). Apophenia is the psychological logical fallacy that is related to but distinct from pareidolia, in which people spontaneously find perceived connections or meanings in things which are random, unconnected or meaningless also called illusory correlations which are a fault in some scientific experiments as well (Psychology, 2009).

Interference is seen in some EVP examples especially those that have been recorded on devices with RLC circuitry. In this cases, it is suggested by scientists that these EVPs are actually examples of radio signals of voices or other sounds from broadcast sources, including interference from CB radios, baby monitors or cross modulation (Tipler, 2004). SSPRS itself has discovered several of our own recordings that have these types of interference effects, though none have been able to produce a voice.

Sometimes the “cleaning up” of a recording can actually create false EVPs by raising the noise floor or filtering it by cutting out certain frequencies, isolation of those frequencies or other enhancements which can cause the altered recording to differ significantly from the original source, more often than not creating an EVP event as opposed to documenting one.

Meteor showers are another possible explanation especially where frequencies above 30MHz are concerned. These types of transmissions are not reflected by the ionosphere and there is a possibility of reflection back down by passing comets or meteors, which leave a trail of ionized particles and electrons as they pass through the upper atmosphere in a process called ablation, causing these broadcasts which normally would flow out into space to be bounced back. These reflected waves are from transmitters which are below the horizon of the received meteor reflection, which means a scattered wave may carry quite a distance, though the chances of a meteor shower interfering can easily be ruled out by checking astronomical charts for known meteor showers or space events during the investigation or recording session. Solar storms may also influence recordings. (Harvey, 1974).

Recording and Analyzing EVP:

            Below is the method that SSPRS uses to collect and study EVP events. This is, in most cases, the standard procedure for teams to collect EVP with few exceptions.

Required Equipment:

  • Digital Audio Recorder with a USB Output (needed to download the audio files to a computer) OR an analog cassette recorder with an external Omni-directional microphone (helps reduce or eliminate the sounds of the gears turning. You will also need high quality fresh clean non-used tapes if you use analog. Microcassette or standard does not matter).


TIP: You should set the microphone on the digital recorder to CONFERENCE. This allows a more effective sampling range around the device.


TIP: If you will be using an analog recorder, you will also need a 3.5 millimeter (standard jack) audio patch cable to transfer your standard cassette/micro-cassette recordings to the PC. Don’t forget the right batteries. Always use fresh.


  • Pen and Paper.
  • Noise-Cancelling Headphones
  • Computer with USB ports.
  • Audio software (Audacity, Cool Edit Pro 2.0, WavePad, Goldwave, etc).

The method for EVP recording presented here is the method by which SSPRS conducts its own EVP sessions and is by no means suggested to be the only one but it is one by which we have been able to obtain results. During an investigation we will pick out our room and clear it of any possible external noise producing items (things that could create artificial artifacts).

After we clear the room of these items and unplug any remaining devices that are not needed, we make a log of the date and time, location and those who are present as well as an accounting of the whereabouts of anyone else present on the location. Once this has been confirmed we use a radio frequency meter to ensure that there is no radio frequency pollution in the area as well as take standard electromagnetic and temperature readings. These are documented as well as photographing the location. After documentation has been done on the measurement and data logs, the investigators present, no more than three sit down on the floor as to minimize noise while the recorder itself is set aside from the group, on a stable flat surface where no investigator can touch it. Ideally, though not always, a video camera is recording the session.




`At this point, the recorder is activated and time stamped vocally with the following script:

“ Date is _____________. Time is ______________. RF field readings are __________. EMF field readings are____________. Temperature readings are____________. Investigators present are_______________. (at this point each investigator should say their first and last name in a normal speaking voice which can help separate possible names recorded later and provide a control for comparison). Location is________________. Standard EVP session now recording.”

A slight pause of approximately one minute is allowed between the time stamp event and the actual session itself which will be run for an average of fifteen to thirty minutes at a time in each location on the site by a team of investigators. EVP sessions are never ran in tandem and only one session is allowed to be in progress at any given time.

During the session, questions are asked that are simple in nature, often easily answered with a yes or no or a number with a pause of 30 seconds to 1 minute between each question asked during which there is absolutely silence on behalf of the investigators. EVP questions are never forceful and must be polite and without ridicule nor with insults (provocation).

At the end of the session, the time keeper (who also keeps the logs) will once again take measurements at 3 minutes till the end of the session for RF, EMF and temperature, logging these on the logbook and audio without breaking the session. At one minute till the end of the session, a one minute silence is imposed to allow for the possibility of any stray sounds to be recorded. At the end of that final minute, the recording is again time stamped EXACTLY as when it opened with the same verbiage and names. After the time stamp, the recorder is shut off as is the video camera.

The set up is then repeated throughout the location until the location has been fully examined. At no point  is white noise allowed to be used or brown or pink or any other type of noise generator. Ovilus also may not be used except for experimental purposes and must be documented when used. If any sounds or events occur during a session, such as refrigerator turning on, coughing, sneezing, etc or heating and cooling system cycling, they are logged and noted with times. Whispering is forbidden as well.

At the end of the investigation, all audio samples are downloaded into files into the computer and appropriately labeled by location and date. You can transfer the analog files by plugging one end of the patch cable into the output (headphone) jack of the analog recorder and the opposite end into your PC’s microphone jack and then use Windows Sound Recorder to capture the playing file, essentially re-recording the original onto the PC.

The files are then split into fifteen minute clips (makes for easier listening than hours at a time) and listened to in our audio program, Cool Edit Pro 2.0 (Adobe Audition) using noise-cancelling headphones, and a pad and pen to track any events that are found during the listening to go back and revisit for further analysis. Once the initial analysis is completed, the sections that are marked for further review are clipped out and saved as an original file without modification. A second copy is then made and that second copy is the one upon which further cleaning may be done if necessary however, SSPRS does not use cleaning or filtering unless absolutely necessary and any thing that is done to any specific sound file must be documented in full, step by step in the analysis log.

When labeling file names of clips believed to contain EVP events, the file name is NOT allowed to contain what we think an event may say, but rather is a random set of numbers. The listener is not told what we think the sound is and must tell us their impressions first as to minimize audio paredolia.

When listening for human voice ranges and analyzing clips, a carefully conducted frequency analysis of what is believed to be a voice clip can often times help rule out conventional explanations and find alternate ones before leaping to the paranormal (SSPRS, 2010).

                                    More on EVP: Frequency Ranges and Sonic Effects:

(from S.P.I Society for Paranormal Investigation, 2010.)



“ Measuring terms:
1,000,000 cycles per second = Megahertz (MHz)
1,000 cycles per second = Kilohertz (KHz)
1 cycle per second = Hertz (Hz)

Some ghost investigators say that a recorded voice in the ELF range is quantifiably EVP because the human voice cannot go below 250 or 300 Hz.

While it is a true general statement that the frequency of the human voice is about 300 to 3000 Hz, this statement is generalized, over-simplified, and not entirely accurate. In fact, the human voice ranges from 20 Hz to about 14,000 Hz.

Here are some more specific facts regarding frequency range of the human voice:
Most energy concentrated below 1000 Hz.
Vowels have most of their energy below 1000 Hz.
Consonants have most of their energy above 1000 Hz.
Harmonics in voice can go above 3500 Hz.

The range of frequencies that young, healthy adults can hear is between about 20 Hz to about 14,000 Hz (some up to 20,000 Hz).
We perceive speech mainly in the frequency range of 500 Hz to 3000 Hz.
The frequencies which have the most significance for speech lie between about 100 Hz and 4,000 Hz.
Human voice ranges from 20 Hz to about 14,000 Hz (typically about 300 to 4000 Hz).
The fundamental frequency (F0) for an adult male voice is around 120 Hz (80-200 Hz).
A speaker with a bass voice will produce sounds with a F0 of between 75 and 150 Hz.
The typical FQ range for an adult female voice is around 220 Hz (140-500 Hz).
A speaker with a soprano voice will produce sounds with a F0 of 400+ Hz.

These frequency numbers are in Hertz (cycles per second):
1                 Approx. beginning of brain waves
6.66           Theta brain waves
7.85           Alpha brain waves
15.7           Beta brain waves
30-30.56   Government VLF stations
32-33        Government VLF stations
34-42        Government VLF stations
50              Approx. Upper limit of brain wave frequencies
60              Produces an audible sound
Here are some other typical frequency ranges:

Thunder – as low as 20 Hz
Piano – 25 Hz to 4,100 Hz
Bass drums – as low as 30 Hz
Bass guitar – 30 Hz to 200 Hz
Bass Tuba – 44-349 Hz
Cello – 66-987 Hz
Guitar – 83-880 Hz
Trombone – 83-493 Hz
French Horn – 110-880 Hz
Trumpet – 165-987 Hz
Clarinet – 165-1567 Hz
Violin – 196-3,136 Hz
Flute – 262-3,349 Hz
Cymbals – up to 15,000 Hz
Squeal of Bats – about 20,000 Hz


Hearing Frequency Ranges are also interesting to note:
Dog Hearing Frequency Range – about 50-45,000 Hz
Cat Hearing Frequency Range – about 45-85,000 Hz
Bat Hearing Frequency Range – about 2,000-120,000 Hz
Porpoise Hearing Frequency Range – about 75-150,000 Hz



Sounds which the human ear can hear range from 0 dB (so faint that only the best hearing person can hear them) up to 180 dB (as loud as a rocket taking off).
Typically, we speak between 45-60 dB loud.
Here are a few more decibel scales:

Leaves rustling – about 10 dB
Stream Flowing – about 15 dB
Whisper – about 20-50 dB
Ticking Watch – 20-30 dB
Bass Drum – 35-115 dB
Organ (orchestral) – 35-110 dB
Quiet Street – 40 dB
Cymbal – 40-110 dB
Violin – 42-95 dB
Quiet Conversation – 45-60 dB
Trumpet – 55-95 dB
Busy Office – 60 dB
Home hi-fi system – about 60-90 dB
Piano – 60-100 dB
Loud Conversation – 70 dB
Normal City Traffic – 70 dB
High-speed electric train – 70-100 dB
Vacuum Cleaner – 75 dB
Hair Dryer – 80 dB
Cafeteria – 80 dB
Slamming Door – 80 dB
Motorcycle – 90 dB
Lawn Mower – 90 dB
Garbage Truck – 100 dB
Screaming Baby – 115 dB
Thunder – 120 dB
Construction Site – 120 dB
Race Car – 120-130 dB
Rock Band – 120-130 dB
Pain Threshold – 130 dB
Jet Taking Off – 140 dB
Rifle Shot – 160 dB
Rocket launch – 200 dB



A simple explanation of a waveform is that it is a graphic representation of a sound wave, which is the result of compressed air pressure propagating away from its source of compression.

A sound wave can be displayed as amplitude against time.

The loudness or amplitude of a waveform is the changing pressure from the peak of the waveform to the trough (the height of the waveform). Amplitude is measured in dB (decibel) on the vertical axis.

The distance between two successive peaks in a waveform is called the period. This measurement of time is shown on the horizontal axis.

A cycle is the amount of time it takes the waveform to go from one amplitude all the way through its amplitude changes, until it reaches the same amplitude again. (The times a sound wave crosses zero vertically.) This range consists of 360 degrees.

The frequency of the waveform is how many cycles it goes through each second, where one Hz (hertz) is one cycle per second.

Pitch refers to the basic frequency at which a sound vibrates, also known as its fundamental frequency, or F0 (“eff-zero”). This also refers to how high or low the sound is perceived. Pitch is often used synonymously with frequency; the higher the pitch, the higher the frequency.

Fundamental frequency (F0) is the lowest frequency of the sine waves composing a complex sine wave. The two higher frequency components are the second and third harmonics, the fundamental frequency is also called first harmonic.” (SPI, 2010).

By using the above frequency tables, a paranormal investigator or parapsychologist could run frequency analysis on any captured EVP and compare them to the  table to eliminate possible rational causes.

In conclusion, this paper has briefly touched upon the history, methods, theories and basic equipment used to research electronic-voice phenomena. This is by no means a complete study of the anomaly that is known as EVP but merely meant to be an introduction to the study of the events themselves and also give basic instruction on how to obtain clean samples of EVP events in the hopes that more researchers will begin to study EVP. The very existence of EVP, if it is indeed a true phenomena, suggests that discarnate survival of the personality is indeed possible  or at the very least that some part of us is left behind.

Whether or not EVP constitutes survival is up to debate.  Alan Gauld, a contributing author to the Parapsychology Handbook, establishes that to clear up the matter of post-death survival, we must establish three basic rules. The first rule states that only those cases that will be counted as evidence for survival are those in which there is a clear and present recrudescence of the personality of a once living human being in its totality whom has suffered bodily death.  To further clarify personality in precise terms: characteristics, attitudes, mannerisms and emotions, memory-knowledge and intellect. Cases in which  only voices, non-interacting apparitional experiences, EVP and ITC alone do not make proof per se for survival as these events may possibly exist outside of the survival of the human being after death (Parapsychology Handbook, 1977).  If we follow this definition of survival, then EVP alone does not prove survival of the entire personality beyond death, but in fact suggests, that EVP may be nothing more than fragments of a person’s personality and psychic memory lost in space and time that we are able to detect on rare occasions under the right conditions which are as of now, unknown.

Only time will tell whether or not the dead do in fact speak and whether or not we should or even can listen to them.





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Warren, J. Understanding EVP, a Practical Demonstration. LEMUR (n.d). Retrieved January 2nd, 2010 from: http://shadowboxent.brinkster.net/lemurEVP.html

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Wolman, B., Dale, L., Schmeidler, G. & Ullman, M. (Eds.). (1977).                                                                         Handbook of Parapsychology.  New York: Van Nostrand Reinhold Company.













About Anthony Justus

Paranormal investigator, writer, seeker of knowledge and truth in all its forms, dark and light. Nothing is what it seems; there is nothing so strange as truth and truth is elusive as the shadow cast in the deepest night.
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