Preferences

Audio I/O

• The two drop-down list controls in this pane is where you configure which device Audacity should use for sound input and output. This basically means which sound card, USB sound device, etc you want to use. If your sound card support multiple sound inputs, e.g. has a microphone input and a line-in, then you select these on the mixer toolbar. No need to adjust this if Audacity is already playing to and recording from the correct place.
• Record in Stereo: If this is checked, recordings you make in Audacity will be stereo, otherwise they will be monaural. Note that the interpretation of mono recordings depends on your system - on most systems making a mono recording of a stereo input will result in the two channels being mixed, but on other systems it could give you just the left channel, for example.
• Play other tracks while recording new one: Check this box if you want to record multiple tracks over top of one another! Record the first track as usual. Then, with this box checked, click record again. The first track you recorded will play, but Audacity will also record a new track at the same time, maybe allowing you to sing harmony with yourself or add real-time sound effects to a recording.
  You may notice that when you play the two tracks you recorded together, they aren't synchronized. This is normal and is not the fault of Audacity. To fix it, you will need to grab the Time Shift tool and slide one of the tracks around until it sounds right.
• Hardware Playthrough (Mac Only): This sets up your computer to send the sound coming in to be recorded straight back out of the speakers, so you can hear what you are recording. Hardware playthrough has no latency and takes no CPU, but is only possible if your input and output are on the same audio device, and that device supports it.
  Windows and Linux users can enable this using your operating system's Mixer, by simply turning up the level for the input you are using and unmuting it.
• Software Playthrough: This enables you to hear what you are recording by taking the data about to be recorded by audacity, and playing it back out of the sound card. This works with any duplex sound card, or combination of sound devices, so you can record in through an external USB device and play back through the computer's built in sound device or vice versa.
  Because of the delays in processing the audio on the computer, there will be some delay or latency in the sound that you hear. It also needs some CPU power, so if you have an old machine and are getting breaks in your recordings try turning it off.

Quality

This panel sets the default sample rate and bit depth for new projects. It does not affect any existing project - to change the sample rate of an existing project, just click on the rate at the bottom of the window and select a new rate from the pop-up menu.

The bit depth affects imported material, if it's copied, as well as newly recorded material. The advantage of the 32-bit float resolution is that effects return material at a this resolution, which improves the final mix, because the computer has more precise material to work with. If you aren't doing any processing then you may want to save some space by setting this to 16 bit, if your hardware supports this.

File Formats

• When importing uncompressed audio files...
  • Make a copy of the file to edit: selecting this means that Audacity will run a little bit slower, but it will always have its own copy of any audio you are using in a project. You can move, change, or throw away your files immediately after you open or import them into Audacity.
  • Edit the original in place: selecting this operation means that Audacity depends on your original audio files being there, and only stores changes you make to these files. If you move, change, or throw away one of the files you imported into Audacity, your project may become unusable. However, because Audacity doesn't need to make copies of everything, it can import files much more quickly this way. If you want to send projects to other people or archive them, then select this option.
  
  
• Uncompressed Export Format: This lets you select the format that Audacity will use when you export uncompressed files, i.e. anything other than lossy formats, such as OGG and MP3. Audacity can output a huge amount of different formats with the Other option, which lets you define any aspect of the multitude of different formats.
  For most users, 16 bit WAV (Microsoft) or AIFF (Mac) files will be the most compatible.
• Ogg Export Setup: Use this control to set the quality of Ogg Vorbis exporting. Ogg Vorbis is a compressed audio format similar to MP3, but free of patents and licensing fees. A normal quality Ogg Vorbis file is encoded with a quality setting of "5". Note that unlike MP3 encoding, Ogg Vorbis does not let you set a bitrate, because some audio clips are easier to compress than others. Increasing the quality will always increase the file size, however.
• MP3 Export Setup: Use these controls to locate your MP3 encoder and set the quality of MP3 encoding. Higher quality files take up more space, so you will need to find the level of quality you feel is the best compromise. For more information, see Exporting MP3 Files.

Spectrograms

You can view any audio track as a Spectrogram instead of a Waveform by selecting one of the Spectral views from the track's pop-up menu. This dialog lets you adjust some of the settings for these spectrograms.

• FFT Size: The size of the Fast Fourier Transform (FFT) affects how much vertical (frequency) detail you see. Larger FFT sizes give you more low frequency resolution and less temporal resolution, and they are slower.
• Grayscale: Select this for gray spectrograms instead of colored ones.
• Maximum Frequency: Set this value anywhere from a couple of hundred hertz to half the sample rate (i.e. 22050 Hz if the sample rate is 44100 Hz). For some applications, such as speech recognition or pitch extraction, very high frequencies are not important (visually), so this allows you to hide these and only focus on the ones you care about.

Directories

Use this panel to set the location of Audacity's temporary directory. Audacity uses this directory whenever you work on a project that you haven't saved as an Audacity Project (AUP file) yet. You have to restart Audacity (close and open it again) for changes to the temporary directory to take effect.
This directory can contain a lot of files and is used a lot, so choose a disk with plenty of free space to put it on. Never put it on a network drive.

Interface

• Autoscroll while playing
  page flips to the right when the cursor travels to the right hand end of the wave display, either during playback or recording. Always keeps the cursor on screen, but may cause breaks in recording or playback if you have a slow machine.
• Always Allow Pausing
  
• Update spectrogram while playing
  Tries to keep the spectrogram updated while playing. This requires a lot of cpu power, and really isn't a good idea unless you're playing a really small piece or have a powerful CPU and plenty of RAM. In combination with Autoscroll while playing this can cause pauses during playback or recording.
• Enable Edit Toolbar
  Gives you a toolbar of a few useful functions. Check out the page on the Edit Toolbar for more information.
• Enable Mixer Toolbar
  Turns on display of the Mixer Toolbar used to control soundcard mixer settings.
• Enable Mixer Toolbar
  Turns on display of the Meter Toolbar, with VU meters you can use to monitor the recording and playback levels of your project.
• Quit Audacity upon closing last window
  Sets Audacity to shut down when the last project window you are working is closed. If you turn this off then audacity will keep re-spawning new blank project windows until you do File > Quit.
• Enable dragging left and right selection edges
  Lets you manipulate selections by clicking on the edges and dragging them along the timeline.
• Enable dragging left and right selection edges
  Sets the transport control button order as:Pause, Play, Stop, Home, End, Record. Rather than: Home, Play, Record, Pause, Stop, End.
• Language
  Lets you change the language of the menus and other onscreen text to the language of your choice. Simply choose the correct option from the drop-down list. Note that for languages with unusual character sets you need the correct fonts installed. If your menus come up all ???? that's what's wrong.
• Minimum of dB mode display range
  This sets up the scale used for logarithmic waveform displays. Because Decibels are logarithmic, it is impossible to have a 0 point on the scale, so some very quiet sounds will display as silence. If you you reduce this effect by increasing the range, then the louder part of the scale gets squashed, so there is a choice of settings for different uses. -48dB is a good compromise for general work.

Keyboard

• Commands/Key Combination List
  All commands in Audacity that can be triggered by a keyboard shortcut are listed here. Click on the shortcut and the assigned keystroke is highlighted in the command/shortcut list. Click on the "Clear" button to erase the keystroke assigned to the function selected in the Commands column.
• Adding new shortcuts/changing shortcuts
  Click on the command in the list. Click in to the field next to the "Set" button and press any key or combination of command key(Shift,CTRL,ALT) and alphanumeric key(everything else). The description of that key or key combo will appear in the field or replace the existing keystroke. By clicking on the "Set" button, you can add or change this key or key combo as a shortcut to the function selected in the Commands list.
• Saving your setup You can export your keyboard shortcut settings for safekeeping or to import into audacity on another machine. Use Save... to save you settings to a file, Load... to load a saved settings file, and Defaults to restore the default audacity settings.

Head over to this page for step-by-step description of the dialog and how to edit the command/keyboard combination list with a text editor.