Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
SampleTank - THE MASTER-QUALITY MIDI SOUND MODULE AND GROOVE WORKSTATION FOR THE MOBILE ARTIST.
LMMS - Make music with a free, cross-platform tool
Fission - Edit audio in minutes, not hours.
Oceanaudio - Ocenaudio is a cross-platform, easy to use, fast and functional audio editor.
MusicBoard - Mb Launchpad is the first Linux launchpad.