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 1.3.12 beta :

• Bug fixes for:
- Cutting or deleting a region in the waveform and label track did not move the labels in advance of the cut
- Incorrect behavior snapping to labels and boundaries with Snap To enabled
- Projects froze if files imported via On-Demand were no longer available
- (Windows 7) Clicking in a file open or save dialog caused files or folders to disappear from the list, and file filtering was broken
- Other import/export, effects and crash fixes
• Changes and Improvements:
- A hover tooltip is now provided if the Mixer Toolbar input selector cannot control the system slider for the selected input
- More intuitive behavior when moving and resizing labels by dragging
- Export Multiple: new option to use a numerical prefix before existing label or track names
- New Equalization preset "Inverse RIAA", with new button to invert other curves
- New Preferences choice for "System" language which is used on first run instead of asking user to choose language

Changes in Audacity 1.2.6 :

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