Audacity is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems

Audiveris is an open-source Optical Music Recognition software which processes the image of a music sheet to automatically provide symbolic music information in MusicXML standard.

The Variations Audio Timeliner is an audio annotation and analysis tool for creating and labeling bubble diagrams. These diagrams can be used to navigate music or other audio for detailed study.