Basic setup for the audacity audio management program

Techniques >Setup for Audacity

Basic Setup for the Audacity Audio Management Program

Audacity is a free, open source computer program for recording sounds into a computer and editing the resulting sounds files. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems. See http://audacity.sourceforge.net/ for supporting information.

Please note that, as an open source project, Audacity has been developed by volunteer programmers. It is as good or superior for most capabilities required for EVP but it is sometimes less intuitive to use, and in some areas, has more technical terminology. As a free program, we feel that it is more than sufficient for EVP and ask for your patience with the developers and for your support of their work.

Since the program is open source, we are able to include it on this compact disk, but please check the SourceForge web site for updates and news of changes. An excellent manual is included on the web site. Please go to the Audacity web site to download the appropriate installation program if you are using a Macintosh or Linux operating system.

The basic steps are documented here to assure that you are able to load the program into your computer and use it as required for EVP analysis.

Installing Audacity:

Place the CD in your computer, and with all other applications closed, open the folder named Audacity and double click on the application named audacity-win-1.2.3. Follow the instructions.

If the install program does not do so, copy the application icon from the START > All Programs list and paste it on the Desktop for future access.

There are numerous secondary programs called “Plug-ins” that are available for Audacity and accessible via the Audacity web site. Plug-ins are usually designed by third parties to satisfy a specialty requirement not currently supported by Audacity. Feel free to add plug-ins as you see fit; however, there are two which should be installed at this time.

The Plug-in folder on the supplied CD, includes the file, VST Enabler.dll and lame_enc.dll in the Plug-in folder at: Program Files> Audacity> Plug-in. VST Enabler.dll will permit you to include other VST type plug-ins. lame_enc.dll will allow you to save files in the mp3 format. The mp3 format is a proprietary compression format and cannot be directly included in an open source application. You will be guided in the activation of this feature.

At this point, Audacity should be ready for use. Simply double click on the application icon to open.

Major Audacity Features

You should become accustomed to using the Manual that is provided in this folder. The Index file is the first page.

In the following instructions, you will learn to:

Prepare Audacity for recording a sound file
Record a sound file
Save a sound file
Save a selected part of a sound file to a new file
Amplify a sound file

Preparing Audacity for Recording a Sound File

When you open Audacity, you will see the standard Menu at the top of the screen. Below the Menu, you will see an array of buttons that are just like what you would see on the typical audio recorder, and they are used in the same way. To the right of the “recorder” buttons, beyond the input and output level meters, are a number of important controls which you should be sure to set before each recording session. The Output and Input sliders allow you to adjust the input and output levels. If your audio recorder does not have a USB interface, when you connect your recorder to the computer, you will need to make sure that Audacity is set to “look” at the input jack you used. Assuming you used the Line In jack on the computer, make sure Line In is selected in the drop-down menu at the far right.

At the bottom-left of the screen is a field titled, Project rate with a number field to the right. In a new recording, that number determines the sample rate which is used to import the file from an audio recorder. When you click on the number field, a list of sample rates will be displayed. We recommend that you capture and store files at either 11025 or 22050. “22050” is 22,050 samples of the sound track per second. When you prepare a sample to send to someone vie email or to post on the Internet, we recommend that you export the sample at 8,000. Please see the “About conversion from Analog to Digital” sidebar for an explanation.

Preferences

Under Menu item FILE > PREFERENCES, the AUDIO I/O tab, decide whether or not you want to listen to your recording sin Mono or Stereo. Select “Stereo” if you are using a stereo recorder. We prefer to hear the incoming recording on the speakers or our head set while we uplad a file, so we have “Show Playthrough” selected.

In the QUALITY Tab, select “Default Sample Rate” as either 11025 or 22050. “Default Sample Format” should be set for 16 bit.

In the FILE FORMAT Tab, select “Read directly from original file” and “Uncompressed export format” should be WAV (Microsoft 16 bit PCM). In the “MP3 Export Setup” area, click on “Find Library,” click on YES and brows to find the “lame_enc” file. It should be stored in Program Files> Audacity> Plug-in

Set up a folder for saving temporary files, and inn the DIRECTORIES Tab, set the “Temp. Directory” to that folder.

If your computer is very slow, uncheck “Enable Meter Toolbar.”

Recording a Sound File

With Audacity configured as described above, you should be ready to upload an audio file from an audio recorder. Follow the instructions provided with your recorder if it has a USB interface. With any recording device that has a headphone jack, connect the headphone jack of the recorder to the LINE IN jack of the computer.

(Note that you may have to use an attenuating cable to match the difference in resistance between jacks. If you have trouble, fist try a different sample rate and then ask Radio Shack for help.)

Note: Everything on the Audacity screen or work area, can be played at one time, and will be merged when the SAVE is used. If you are opening multiple files, and do not intend to merge them, initiate a new copy of Audacity for each new file. (Menu item FILE > NEW)

Open Audacity, and as you depress the PLAY button on the recorder, click on the RED BUTTON in the recorder controls of Audacity. You should begin to see an audio trace form on the screen.

Click on the ORANGE SQUARE BUTTON in the recorder controls of Audacity to stop recording.

A note about file formats

We have learned that some audio recorders will only save sound files as WMA, which is a proprietary format. Because it is proprietary, Audacity cannot open the files and there are no near-term plans to ad a plug-in as they have for mp3, making it necessary to purchase a different audio manager or record the audio into the computer via a cable between the earphone jack and the computer's mic jack. See http://aaevp.com/techniques/technique_evp10.htm

The only audio recorder we are aware of that only use WMA are some of the Olympus recorders. We recommend that, when selecting a recorder for purchase that permits transfer of files, rather than audio stream, you make sure that it will save files as mp3 or wav, preferably Windows PCM (*.wav).

If you already have a recorder that only uses WMA files, we have found a possible converter that is free and works. We do not know for sure that it does not contain surprises later. For instance, even though they say free, they may want money after a trial period. At any rate, click on this button: and download the program. To convert to wave, the program requires that you install Panda as well. You will see that option as you install the program.

If the program does want money later, the going price seems to be between $10 and $25. Find others by searching for "WMA to WAV conversion." An alternative is to buy a sound management program that supports WMA files. Goldwave would be an example for around $45

We understand that this program is supposed to work in a Mac.

Disclaimer: Use at your own discretion. We have used this product but not long enough to know if there are any hidden problems. Please let us know if you do have trouble with the program.

Save a Sound File

Audacity saves files in the “.aup” format, which is optimized for Audacity. If you intend to continue to exclusively use Audacity as your sound editor, then simple select Menu item FILE > SAVE PROJECT.

About Conversion from Analog to Digital

The sound you hear in the air is analog, meaning that it is continuously changing. The typical audio cassette recorder is analog throughout the circuit. IC recorders convert the analog signal to digital for storage and convert it back to analog for output to the speaker or earphone. Computers also convert whatever is input on Line In to digital and then back to analog to be heard in the speakers. The quality of reproduction for the signal is a function of the sample rate and the sample format, which is the size of the sample “word.”

In audio theory, the Nyquist Sample Rate is the minimum number of times each cycle must be sampled to permit accurate reproduction of the original signal. That sample rate is twice the original frequency. As an example, most of the human voice frequencies are below 4,000 Hz (Hertz = cycles per second). Therefore, for digital signal processing, telephone equipment manufacturers build equipment that sample the voice signal 8,000 times a second or twice the frequency they wish to reproduce.

While a person’s voice on a telephone call is recognizable, it does not sound as clear as when heard in person. Although fine for voice, the fidelity of the telephone circuit is very poor. Music quality equipment is usually designed to faithfully reproduce signals of 20,000 Hz or more, and have digital processing sample rates to agree. Music CDs have a sample rate of 44.1 KHz, which will allow for reproduction of a little over 20 KHz signals (20,000 Hz).

Each sample gives results in a data “word,” and the number of bits in the word determines how many divisions are used for amplitude. In other words, a four bit word would only be able to reproduce a sound at zero level, ¼, ½, ¾ and full power. Inexpensive digital recorders use smaller words giving a lower quality reproduction of the voice. Computer, audio editing software usually offer 8, 16 and 32 bit sample format. Default for Audacity is 16 bit.

Larger numbers equal larger files.

For EVP, we recommend that you use a sample rate of 11025 or 22050 Kbps with a 16 bit format, WAV (Microsoft 16bit OCM) file format. Mono or stereo is optional. Save the file for sharing as mono 8000 Kbps mp3.

To save the file for future editing or use with other applications, select Menu item FILE > EXPORT AS WAV. Make sure you put the file where you can find it later.

To save the file for sharing with others, first click on the name of the file in the work area and select SPLIT STEREO TRACK in the dropdown menu.

Click on The “X” at the upper-left corner of the sound file in work area to delete one of the files. Click on the name of the remaining file and select MONO from the dropdown menu. At the bottom-left of the screen, click on the PROJECT RATE number field and select 8000 Hz. (The new setting only applies to the exported file.) Select Menu item, FILE > EXPORT AS MP3. If the system asks you for the “lame_enc.dll” file, use the browser to find it in Program Files> Audacity> Plug-in. You should only have to do this once.

“Ogg Vorbis” is a compressed file format similar to MP3, however, it is not commonly used amongst EVP experimenters.

Save a selected part of a sound file to a new file

A portion of the sound track is selected by placing the cursor over one limit of what you wish to edit, depress the left mouse key and drag the selection tool to the other limit. Release the mouse key. You can select the entire sound file by clicking on the blank area above the SOLO button at the left of the track. Select all on the screen with “Ctrl + A.”

Follow the Save a Sound File instruction above to save the selected portion of the track as a new file.

Hints

It is possible to accumulate a very large collection of sound files when working with EVP. Be sure to plan your filing system early, and consider using permanent storage media, such as CDs for old files. A useful filing system is MY DOCUMENTS > EVP SESSIONS > {session folder}. After loading the file into your computer, save it into a session folder named: SESSION {place}{date}. As you analyze the file, save selected clips containing EVP into the same folder. We later make a copy of the very best examples and save them in a “Class A” folder. For those, we also try to label them so that we can go back to the original sound track.

Occasionally back up your EVP SESSIONS folder on CD. You can use Read Write CDs, but as you accumulate sufficient files, save the old ones onto a Read Only CD for permanent storage and delete those files from your hard drive. At that point, you will still have your Class A examples in your computer for future reference.

If you enhance the newly imported sound track as you examine it, such as amplify a small selection to see if it contains an EVP, be sure to either work from a copy or faithfully use the UNDUE arrow. Of course, SAVE first before analysis. It is a good practice to save the clip in its original form to a new file, add a little silence and then copy and paste the clip after the silence. Then, you can edit the second copy of the clip and have the original in the same file to compare.

Over enhancement of a sound track can change how you hear the EVP and even the meaning of the message. For personal use, it is okay to do whatever is necessary to figure out what is said, but we recommend that you do no more than amplify and possibly a little filtering for EVP that will be played for others. Please only play Class B or better for others. Happy recording!


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