Introduction to Audacity
Version 20040511B

by
Barry G. Wong
World Wide Web: https://mythanks.tripod.com/
All of the textual content and graphical content
in this document are by Barry G. Wong,
except where otherwise specified.

# I. Sound

## A. Compression

Think of a balloon inflated with air molecules.

 Uncompressed Compressed Rarefied(Stretch the balloon)

# II. Capture and digitization of sound

## A. Analog

Signals are continuous.

## B. Digital

Digital electronic computers use numeric digits to represent information.

### 1. Binary

• Many digital computers represent information with a sequences of the two digits, 0 and 1.

• The computers might use one electrical voltage to represent 0 and another voltage to represent 1.

## C. Analog to Digital Conversion (ADC)

• Audio or video is converted from an analog (smooth) format to a discrete (broken-into-pieces) format.

• Then the results are encoded as sequences of zeros and ones

• Then digital computers, by working with those sequences of zeros and ones, can handle that audio or video.

## D. Sampling

### 1. Earplugging analogy

• Suppose you are listening to a radio news report which lasts 3 minutes.

• Now imagine that you put earplugs into your ears for 10 seconds, and then remove the earplugs.

• You would have missed some of the news report.

• Suppose you continue alternately plugging your ears for 10 seconds and then unplugging your ears in this way repeatedly until the end of the news report.

• Then, you would have heard only a few samples of the news report. You would have been hearing samples not very frequently. In other words, you would have sampled with a low sampling frequency.

• If someone asked you to say what was in the news report, then you might be able to provide only a small amount of information.

• Now imagine that you put earplugs into your ears for only one-half of a second, and then removed the earplugs.

• Suppose you continued alternately plugging your ears for one-half second and then unplugging your ears in this way repeatedly until the end of the news report.

• Then, you would have heard many samples of the news report. You would have been hearing samples fairly frequently. In other words, you would have sampled with a high sampling frequency.

• If someone asked you to say what was in the news report, you might be able to provide a lot more specific information. The accuracy of your summary might also be higher.

### 2. Glimpses per second

Look at the same sound waveform viewed at low and high sampling frequencies.

 Low sampling frequency High sampling frequency Waveform being sampled

## A. Apply appropriate security procedures

### 1. Antivirus software

• In general, whenever you receive software – via downloading or via other means – use appropriately updated antivirus software to scan the received software for viruses, malware, and similar threats.

### 2. Personal firewall software

• Consider use of appropriate personal firewall software, if appropriate.

### 1. Small files

#### a. Browsers

##### (1) Microsoft Internet Explorer

2. Click on Save Target As....

### 2. Large files

##### (1) GetRight
1. Go to http://www.getright.com/ .

3. Follow appropriate instructions for use of that software.

# IV. Compression (and decompression) software

## A. Compression software for Microsoft Windows (“Windows”)

### 1. Enzip

• EnZip is for use with .zip compressed files.

# V. Audacity

1. Search for

Audacity

## B. Open source software

### 1. Source code

• A (for example) person types special instructions in English (or another “natural language”) for a computer.

• This set of instructions by (for example) a person for the computer is the source code.

### 2. Executable code

• A computer uses special procedures to translate, adjust, and merge the source code into instructions that are simpler and more efficient for the computer.

• These translated, adjusted, and merged instructions that the computer can execute or follow are called executable code.

• In general, people cannot read executable code very easily.

### 3. Open Source or Closed Source

• Some people or groups keep their source code secret as their intellectual property. This approach is called Closed Source.

• Some people or groups allow their source code to be distributed and viewed (and perhaps modified) freely by others under specific conditions. This approach is called Open Source. Audacity is an example of Open Source software.

## D. Installation

### 1. Windows version

#### a. Software

##### (1) Audacity
1. Exit other programs.

2. Double-click on the audacity-win-1.2.1.exe icon.

#### b. Documentation

##### (1) Manual

2. Make a new folder (for example, in the My Documents folder), and rename the new folder:
AudacityManual

3. Double-click on the icon for audacity-manual-1.2.zip.

4. Using EnZip (or other .zip management software), extract all the files from audacity-manual-1.2.zip into the new folder which you had named AudacityManual.

5. Double-click on the AudacityManual folder icon.

6. Double-click on the audacity-manual-1.2 folder icon.

7. Double click on the index.html file icon.

## E. Initial setup

### 1. Preferences

#### a. Safety (in case of deletion of original source audio)

##### (1) File > Preferences... > File Formats > When importing uncompressed audio files into Audacity > Make a copy of the file before editing (safer)
• This option uses more disk space, but might help, especially if you delete the original file containing the audio captured.

## F. New project in Audacity

### 1. Windows

1. Launch Audacity (Double-click the Audacity icon, for example).

2. Click File > Save Project As...

3. Browse to an appropriate location.

4. Type a file name (without the file extension).

5. Click Save.

## G. Recording

### 1. Line in

1. Use the proper cable(s) (and, if necessary, adapters) to connect your line-level sound-source (for example, the Monitor jack or Line Out jack of an audio-cassette player) to the Line In jack of the sound card in the computer system with Audacity.

1. Start playback of the sounds (for example, press the Play button on the audio-cassette player).

2. Shortly before you hear the first sound to be recorded, click on the Record button [the button with the red dot () in the Control Toolbar] in Audacity.

3. Click and drag the Input Volume slider (the slider is to the right of the picture of the microphone in the Mixer Toolbar) to get a strong (but not too strong) signal.

4. After you hear the last sound to be recorded, click on the Stop button [the button with the yellow-orange square () in the Control Toolbar] in Audacity.

5. In the Menu bar, click File > Save Project.

## H. Cutting and Pasting

1. To prepare to play the recording from the beginning, click on the Skip to Start button [the button with the leftward-pointing magenta double triangle (│◄◄)].

2. Click on the Play button [the button with the rightward-pointing green triangle ()].

3. Click and drag the Output Volume slider (the slider is to the right of the picture of the loudspeaker in the Mixer Toolbar) to get an appropriate (for example, listening) level.

4. Listen and watch the timeline-pointer (vertical line) move across the waveform (wavy line that stretches horizontally) representing the sound that you recorded. Find an excerpt that you want to move.

5. If you wish, click on the

• Zoom In button [the button with the blue plus sign (+) in a magnifying glass]or

• Zoom Out button [the button with the blue minus sign (-) in a magnifying glass].

1. When you hear the beginning of an excerpt to be moved, click on the Pause button [the button with the blue double vertical bars ()].

2. Click and drag horizontally along the waveform from the beginning of the excerpt to the end of the excerpt.

3. Click on the Stop button [the button with the yellow-orange square () in the Control Toolbar] in Audacity.

4. In the Edit Toolbar, click on the Scissors picture or
in the Menu bar, click Edit > Cut.

5. Click at the location where you want to put the excerpt.

6. In the Edit Toolbar, click on the Clipboard picture or
in the Menu bar, click Edit > Paste.

7. In the Menu bar, click File > Save Project.

## I. Export for external playback

2. Then

• to make a high-quality (but big) audio file,
(in the Menu bar) click Export As WAV

• to make a medium-quality audio file (that is smaller, but with some almost-inaudible sound-parts discarded),
Export As Ogg Vorbis...

1. Browse to an appropriate location.

2. Type a file name (without the file extension).

3. Click Save.

4. In the Menu bar, click File > Save Project.

## J. Exit from Audacity

• In the Menu bar, click File > Exit.

# VI. Terms

Product, brand, and trade names in this and future communications may be trademarks or registered trademarks of their respective owners. Barry G. Wong and the Equinet Broadcasting Network shall not be liable for any errors, omissions, or lack of appropriateness, timeliness, or accuracy in, for your use of or your inability to use, or for any other aspect or matter relating to this or related communications.

At the time of writing, Barry G. Wong and the Equinet Broadcasting Network do not purport to represent any parties mentioned in this communication other than Barry G. Wong and the Equinet Broadcasting Network.