Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Bosca Ceoil - A free, easy to use tool for creating music.
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Zynewave Podium - Podium is a modern digital audio workstation (DAW) for Windows.
Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.
Renoise - Renoise is a digital audio workstation.