Audacity is a free audio editor. You can record sounds, play sounds, import and export WAV, AIFF, Ogg Vorbis, and MP3 files, and more.

Use it to edit your sounds using Cut, Copy and Paste (with unlimited Undo), mix tracks together, or apply effects to your recordings. It also has a built-in amplitude envelope editor, a customizable spectrogram mode and a frequency analysis window for audio analysis applications. Built-in effects include Echo, Change Tempo, and Noise Removal, and it also supports VST and LADSPA plug-in effects.

Changes in Audacity 1.3.5 beta :

• Recording / Playback:
- Several bugs fixed so that latency correction should be better, and more devices work correctly. Problems with invalid sample rates under Linux should be much rarer.
- Newer version of Portaudio library.
- New feature to record onto the end of an existing track (hold Shift while clicking Record).
• Import / Export:
- Updated versions of Libogg, Libvorbis, Libflac, Libsndfile and Twolame libraries.
- Handling of unsupported file formats more informative.
- Handling of file names with slashes on OS X improved. New dialog allows replacement of illegal file name characters on all platforms.
• Interface:
- Improved scaling and layout for rulers and VU meters.
- Envelope fixes/improvements including full control of undo/redo.
- New keyboard shortcuts and improved menu navigation.
- Preferences: More intuitive tab arrangement. New options for mute/solo and Metadata Editor behavior. Language can now be changed without restart.
- Expanded Build Information tab.
• Effects:
- New Vocal Remover plug-in, improvements for Generate effects.
• Compilation:
- Fixes when building Audacity with libraries disabled.
- Improvements to make Mac and Solaris builds easier.
• Security:
- Full fix for issue CVE-2007-6061 on systems where temporary directories can be changed by other users (thanks to Michael Schwendt).
• Miscellaneous:
- Updated translations for many locales.
- Several stability improvements.

Changes in Audacity 1.2.6 :

- Fix memory leaks on Windows.
- Correct font size problems.
- Enable missing FLAC support.