What are some alternatives?
When comparing Free Audio Editor and DarkWave Studio, you can also consider the following products
SoX - Sound eXchange is a command line utility that can convert various formats of computer audio files...
Amadeus Pro - #
Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.
WaveShop - Open source audio editor
Zynewave Podium - Podium is a modern digital audio workstation (DAW) for Windows.
Avid Pro Tools - Music software for Mac or PC to create audio with up to 128 audio tracks.