Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Audio Hijack - Record any audio, with Audio Hijack!
TwistedWave - TwistedWave is one of the unique audio editors that allow you to edit your music file online without any installation.
WaveShop - Open source audio editor
Studio One - Studio One raises the bar for music production software. Developed by PreSonus, this platform has been used by both professional and amateur artists to make live and studio recordings.