Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Fission - Edit audio in minutes, not hours.
Spek - Spek helps to analyse your audio files by showing their spectrogram.
Audio Cleaning Lab - Looking to clean up your song recordings? Download SOUND FORGE Audio Cleaning Lab, the professional solution for cleaning & restoration with advanced ProAudio technology.
SoX - Sound eXchange is a command line utility that can convert various formats of computer audio files...
LMMS - Make music with a free, cross-platform tool