Techniques >Recording EVP

Recording Sound into a Computer

The AA-EVP recommends that anyone working with EVP use a computer to manage the resulting sound tracks. Yes, people were successful in recording for EVP many years before computers were available. You do not need one now if you are using a reel-to-reel or cassette recorder; however, these recorders generally do not perform as well for EVP as do digital voice recorders, and it is not economically practical to use a digital recorder without a computer.

The additional advantages of using a computer for EVP are that it is possible to clip a segment of a longer sound track to preserve just the phenomenal utterance and perhaps the experimenter's voice asking a question. The EVP clip can be easily saved to the hard drive, and later, saved to a CD for archiving and easy retrieval. It is also possible to make the EVP clip into a smaller audio file for sharing with others via the Internet. Probably the most important use of a computer for EVP is the ability to more easily find the utterance on a sound track, and if necessary, amplify it and/or remove background noise to make the utterance more easily understood.

Transferring sound into a computer is not complicated. In effect, the computer is used as an audio recorder. There are a few setup issues that must be resolved the first time you transfer audio, but after that, the process should be routine.

Setting up the Computer for Recording

There are two types of connection between a recorder and a computer: USB port and ear plug output.

If Connecting a Recorder via USB Port

1. If your audio recorder has a USB port for connecting to a computer, then that is the optimum method to use. You should be able to connect your recorder following the instructions that  came with the device, and see a folder representing your recorder's memory on the computer desktop.

2. For all connection methods, create a folder in My Documents and title it something like "EVP Sessions." Open that folder and open a new folder within it titled in a way that uniquely identifies the sound files to be transferred from the recorder. As an example, if the recordings are the first attempt to reach a loved one under controlled conditions, then title the folder with that information and the date: 05-20-2006 Contacting Uncle John.

3. Open the folder representing the audio recorder, select and "slide" the files representing the recordings into the new folder. We recommend that each file be given a name that will help you see at a glance where the file was recorded, or in some way, a unique identifier. This will be important when you go looking for a particular recording years later.

4. At this point you should be able to open the audio file with either the general purpose audio editor or with the one provided by the recorder manufacturer. We recommend that you save audio files as a Windows PCM (*.wav) file format. If the recorder does not save in this format, and if you cannot use the supplied audio editor program to convert the files to this format, then we recommend that you use the audio cable procedure described for recorders not equipped with a USB port.

If Connecting a audio recorder via an audio cable

If your audio recorder does not have a USB port for connecting to a computer, then it is necessary to connect the recorder to a computer via a patch cord between the earphone jack of the recorder and the microphone input jack of the computer.

First, make sure the computer is "looking" at the right input jack, usually Line In (may be Sound In).  On a PC desktop, click on: START > SETTINGS > CONTROL PANEL > SOUND MANAGEMENT.  Select the Audio tab and then select Volume under SOUND RECORDING. (See Figure 1) You will see volume controls and you will want to select LINE IN. Set the level control to about 50% to begin. (See Figure 2)

Access the playback Volume Control by clicking on the Sound Playback Volume button as shown in Figure 3. This control can also be accessed  by double clicking on the speaker icon that is usually in the lower right corner of the desktop in the "tray," or by using OPTIONS > WINDOWS MIXER in Audition. This control is accessible in Audacity in the upper-right of the screen.

Making the Physical Connection

The computer should have a Line In somewhere on the back of the computer enclosure.  It may be on a speaker.  If all you have is a Microphone In jack, then you may need to use an impedance matching cord.  (It can get to be complicated trying to match inputs and outputs, so the best thing to do is plug in and see if it works.)  An impedance matching cord is designed to connect the low impedance of the Speaker Out jack in a recorder (around 8 ohms) to the high impedance of the Line In jack of the computer (around 10K ohms).  Such a cord is available at Radio Shack.

(Most modern electronic devices use transistor coupling circuits that automatically adjust for the differences between resistances, so we recommend that you experiment before buying special cords. If you do have to purchase an impedance matching cord, make sure to mark it well because they are often indistinguishable from ordinary cords.)

(Another way to attempt matching a recorder to a computer is to change the sample rate of the recording software in the computer. For instance, if 11025 Kbps just gives you noise, try 22050Kbps.)

The Audio Management Program

Most audio editing software can be used as an audio recorder.  On a PC, look under START > PROGRAMS, ACCESSORIES > ENTERTAINMENT for something like a Sound Recorder.  You can use this as a recorder as well. You can find a list of audio programs at Selecting Software to Manage Audio Files

Recording into a Computer and Audio File Management

Audio management programs can be used as an audio recorder. In fact, they even have controls like an audio recorder. Almost any audio program will do for EVP. The list shown at Selecting Software to Manage Audio Files is short because we have given up trying to keep up with all of the new ones on the market. The ones shown there have been dependable from the early days. Audacity is free and we highly recommend that you learn to use it as your primary tool.

Specialty programs that just decrease noise or slow down the audio work well and are easy to use, but you will find that Audacity has the same features.

We recommend that caution be used in "enhancing" audio files in an effort to find or improve an EVP. Here are a few considerations:

• If you are recording just for yourself, then do whatever works for you. Be careful to use discernment, though. It is possible to change the meaning of an EVP with processing.

• If you are planning to share your EVP with others, then it is best to only amplify and perhaps apply a little noise filtering. Always tell the person what you have done. In fact, we like to provide the original followed by the enhanced version so that the person will know what they are hearing. Here is an example recorded at the Winchester Mystery House The original is first, and then an amplified version (please use a headset):

It is not redemption

(In this case, we feel that "It is not redemption," is a reference to the idea that building the house did not redeem the Winchesters from their responsibility for the harm caused by the weapons they made and sold--just a theory.)

• Save the audio file as a Windows PCM (*.wav) file format for enhancement and storage. That will preserve most of the detail of the recording. We recommend a sample rate of 11025, mono and 16 bits.

• Save examples for posting on the Internet or sending via email as mp3 files. Caution the receiver that they should ask you for the *.wav version if they want to try editing it.

There is additional information about using a computer to record at Computer Recording.

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