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Techniques Recording Sound into a Computer
Modern digital recorders are designed to interface with a computer, and permit easy transfer of information from recorder memory to computer memory. In practical application, it is expected that a practitioner will use a computer for sound file storage, analysis of raw files and possible enhancement.
It is possible to clip a segment of a longer sound track to preserve just the phenomenal utterance in EVP and perhaps the experimenter's voice asking a question. The clip can be easily saved to the hard drive, and later, saved to a CD for archiving and easy retrieval. It is recommended that archival files be saved as *.wav files, but it is also possible to convert the clip into a smaller mp3 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.
Newer recorders permit direct transfer of files via a USB interface, or by inserting a recorder memory card into the computer. However, older recorders did not have this capability and it was necessary to transferring sound into a computer by "playing" the recorded sound file and using the computer as an audio recorder. There are a few setup issues that must be resolved the first time you transfer audio using this method, 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
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.
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. 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:
(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.)
There is additional information about using a computer to record at Computer Recording.
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