The Track Pop-Down Menu appears when you click in a track's title.
This lets you access a few special commands that apply to individual
tracks.
Name... - lets you change the name of the track.
Move Track Up - exchange places with the track above this one.
Move Track Down - exchange places with the track below this one.
Waveform - sets the display to Waveform - this is the default way
of visualizing audio.
Waveform (dB) - similar to Waveform, but on a logarithmic scale,
measured in decibels (dB).
Spectrum - display the track as a spectrogram, showing the amount
of energy in different frequency bands.
Pitch (EAC) - highlights the contour of the fundamental frequency
(musical pitch) of the audio, using the Enhanced Autocorrelation
(EAC) algorithm.
Mono - makes this track a mono track, meaning it is played out of
just one speaker, or played out of the left and right speakers
equally.
Left Channel - makes this track come out of only the left speaker.
Right Channel - makes this track come out of only the right speaker.
Make Stereo Track - if there is another track below this one,
joins them to make a single stereo track, with the top track
representing the left speaker, and the bottom track representing
the right speaker. When tracks are joined into a stereo pair,
all edits automatically apply to both the left and right channel.
Split Stereo Track - if the selected track is a stereo track
(a pair of left and right tracks joined together as a single track),
this operation splits them into two separate tracks that you can
modify and edit independently.
Set Sample Format - this determines the quality of the audio data and the amount of space it takes up. 16-bit is the quality used by audio CD's and is the minimum quality that Audacity uses internally (8-bit audio files are automatically converted when you open them). 24-bit is used in higher-end audio hardware. 32-bit float is the highest quality that Audacity supports, and it is recommended that you use 32-bit float unless you have a slow computer or are running out of disk space.
Set Rate - sets the number of samples per second of the track.
44100 Hz is used by audio CDs. Tracks can have different sample
rates in Audacity; they are automatically resampled to the project
sample rate (in the lower-left corner of the window).