Audacity helps you record sounds from various sources and also lets them edit the resulted sound track in some simple, basic ways. As cross-platform and Open Source software, this represents a nice achievement for the team behind it, a team that promotes freedom of speech and freedom to improve upon the capabilities of this specific software.
The app is particularly useful when you need to record live audio from external sources, such as the microphone or the line-in device. Additional functionality enables users to record the playback from the computer with no quality issues at all. With this, you can save the music from cassettes to MP3 and various other common formats.
Pitch, speed and various mixing procedures are supported.