Audacity program is a free audio editor, running on different operating systems, with several files at once. Audacity can be downloaded for free, it has an open source code. The application has many features, so it is difficult to outline only one kind of implementation.
With Audacity you can:
Audacity is very good for the beginner in sound engineering: its interface, created on the basis of wxWidgets library.
Hotkeys system facilitates work with the application. Audacity audio editor is also known for its free distribution.
You can download Audacity for free on our site.