Audio tracks contain digitally sampled sounds. In Audacity, a channels of sound is represented by one mono audio track, a two channel sound by one stereo audio track. Each audio track has a sample rate: common values include 8000 (telephone), 16000 (speech), 22050 (many games of recent years), 44100 (CD Audio), and 48000 (DAT).
From Audacity 1.2 on, you can specify a different sample rate for each track. You can import audio of any sample rate or bit depth and Audacity will resample and convert it to the project rate and bit depth on the fly, as well as upon Export. You can choose different sample rate conversion qualities for playback and Exporting.
(Note that in Audacity 1.0, all tracks must be at the same sample rate as the project.)
