Fission - Edit audio in minutes, not hours.
Matchering - Open-source audio mastering app that masters music based on any reference track you provide.
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.
eMastered - eMastered makes a song sound better through online mastering.
LMMS - Make music with a free, cross-platform tool
Audio Mastering - Pro quality, fully functional audio mastering application for iPad.