As of December 2015, some free multi-track recording studio software options include MultiTrackStudio Lite, Audacity and Ardour. MultiTrackStudio Lite is compatible with Windows and Mac OSX and is the free version of MultiTrackStudio. Users can record up to three tracks with this software.
Audacity is an open-source application that is compatible with Windows, Mac OSX and Linux. It supports multi-track recording and editing of sound files in various formats, including MP3, WAV, FLAC and AIFF. It lets users apply special effects to their recordings, such as changing the pitch.
Ardour is compatible with Mac OSX and Linux. It supports an unlimited number of tracks and accepts sound input from various sources, including USB and Firewire.