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.
Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.
Jokosher - Jokosher is a simple and powerful multi-track studio.
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Fission - Edit audio in minutes, not hours.