Using a Computer to Record for EVP

These are the fundamental steps for using a computer as an audio recorder for EVP. Once you have established that you can record the phenomenal utterances in this way, we encourage you to explore variations of this theme:

Tools For Using a Computer

You will need a personal computer; however, it need not be a very powerful one.

1. The computer must be equipped with a microphone connection.

2. The computer must be equipped with a computer application that simulates a tape recorder. There are a number of good ones. See the Resources pages for a short list. (Audacity is a free (Open Source) program that is very effective for EVP.)

3. You need a microphone that is compatible with a computer audio card. If you experience a buzz when trying to record with a microphone designed to be used with a standard audio recorder, you may need to purchase a microphone specifically designed for a computer. Some experimenters use a splitting cable that allows two mono microphones to be plugged into the microphone input to the computer. They record in mono and place one microphone near a computer cooling fan for background noise and the second on the desk top to record questions.

4. About 100 Meg of extra hard disk memory for audio files is suggested and a way to transfer saved audio files to CD is a plus.

Sound Source

You will want to have a sound source that can be placed near the microphone. Research has shown that the communicating entities use available audio energy to form their words. EVP Experimenters have found that the entities will actually remodulate ambient sounds as they are picked up by the microphone, and within the electronic circuitry. Computers usually have a relatively quiet recording circuit, so it is recommended that background sound is provided during the recording process.

The screen print of the audio editor, Audacity, shows a sound file containing words spoken by the experimenter and the EVP, and the relatively volume of each compared to the background noise. Use this as an example of a useful loudness for background noise.

Here is the audio file: Betty's in there

Almost all attempts to improve the Quantity and Quality (QQ) of EVP are different forms of energy modification, as opposed to different forms of psi detection. People try every imaginable form of sound in an effort to record more EVP that are more easily understood. Here is a guide for the selection of audio noise:

1. White noise was used in the early days of EVP because the only electronic device available to people for noise generation was the radio turned off-station. That produced various versions of what is known as "white noise;" however, the human voice is mostly in the range of 200 to 4,000 hz. Since most of the audio energy in white noise is not used for voice, any sound source more tailored to human voice is better for QQ. A common household fan, for example.

2. Amplitude modulation (as in AM radio) has been found to be a little better as a sound source than frequency modulation (as in FM radio). We think this is true because natural voice is made of variations in both frequency and amplitude, and FM sources of sound do not generally have amplitude variations. Digitally generated noise is not as effective as "live" noise found in the environment. For instance, we hear of more QQ from running water than from digitally generated white noise.

3. Use of more than one sound source will cause layering of EVP. For instance, we once used a small water fountain which produced a tinkle of noise, along with a large household fan which produced more human voice frequencies. The resulting recording had EVP that sounded like normal voice in tone with elfin-sounding voices present at the same time. This is very distracting and points to the need to manage background sound to optimize human voice frequencies.

4. Some inexpensive digital voice recorders have relatively noisy audio circuits. We think this is because of the low sample rate and resulting first significant bit error due to small word size of each sample. See A Testable Hypothesis Explaining EVP Formation in Digital Recorders for a possible explanation. The noise produced in these lower quality recorders is excellent for the formation of EVP, making digital voice recorders very useful for field recording. The noise from cassette recorder motor drives turns out not to be useful for EVP, making an external microphone necessary for these recorders. Also, the tape hiss is noise produced at the wrong part of the electronic circuit for EVP voice formation.

5. A recording of crowd babble that has no distinguishable words will work. AA-EVP offers a Portuguese language, crowd babble sound track that has been made available to us by Sonia Rinaldi. We do not recommend the use of any broadcast noise in which discernable voices of any language are present.

Using an External Audio Recorder

You can record into a stand-alone audio recorder and then play the results into the computer for listening and editing. See Recording Sound into a Computer for instructions. This is a good way if you intend to archive all of your recordings, because a typical two-minute recording can produce a computer file of two to three Megabits. You can store the audio file on the tape rather than in the computer; however, we prefer storing files on a Compact Disk.

Recording Session

A typical recording session is about two minutes. You will want to listen very carefully to every click and syllable you record—sometimes many times, so two minutes is just about right.

1. In Adobe Audition, under FILE, selecting NEW and then Sample Rate = 11025, MONO and 16-BIT. This will produce a 2.6 Meg file at two minutes recording time.

2. In the conversion of the analog sound of your voice to the digital sound in a computer, faithful reproduction of the analog sound requires at least two samples per cycle. We can hear up to around 22,000 Hz, but human voice is pretty much below 4,000 Hz. Therefore, a sample rate of 8,000 Hz will faithful reproduce the majority of human voice frequencies. This has traditionally been the practice of telephone companies. We recommend that you use a sample rate of at least 11025 so that you can preserve some of the higher frequencies, which tend to help voice recognition. There is sometimes a problem with converting *.wav format to mp3 when a lower sample rate is used.
   
   We use 22050 stereo because we like the fidelity and because we like the sound in both ears. A 32 bit digital word, as opposed to 8 or 16, seems a little overkill.

3. Essentially the same instructions apply to Audacity. See Setup for Audacity for instructions.

4. Follow the instructions at Basic EVP Recording Techniques for your initial recording effort.

Recording directly into a computer for EVP can be very effective; however, it is usually necessary to add background noise because the computer sound circuit is usually music quality.

An Experiment

Since a computer is capable of supporting stereo sound, the use of a single microphone in stereo mode offers some interesting possibilities. For instance, theory has it that the words in EVP are formed in the electronic circuit, and that no two recorders will (as a rule) record the same EVP at the same exact time. When being used in the stereo mode, a computer is technically two recorders--left and right channel. In principle, it should be possible to record using one microphone across the left and right channels, and then to invert one channel and average the two channels in a audio management program. The result should be zero signal as the two identical signals from one microphone cancel one another out. If an EVP is present, it should be on only one of the two channels, and therefore survive the cancellation. If this is true, then this may be an effective way to recover the EVP from the noise.

This could be accomplished in real-time to reveal the voice as it is spoken. The problem here would be in recording Class A or at least understandable words.

One technical issue in this is that the left and right channels of a stereo input to computers are not always well balanced. In other words, the left channel may have a little more background noise than the right, or perhaps a little more zero off-set. It is not clear how to manage this, unless a pair of variable resistors (volume controls) can be places between the microphone and the splitter.

We have not had the time to test this approach, so we must depend on the ingenuity of people such as yourself to see if this is a valid approach, and if not, why. We always need to know if an idea fails and try to learn why, so please let us know via email.

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