Audacity ® | Free, open source, cross-platform audio software for multi-track recording and editing.

Free, open source, cross-platform audio software

Audacity is an easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems.
Developed by a group of volunteers as open source.

Source : Audacity ® | Free, open source, cross-platform audio software for multi-track recording and editing.