Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Spek - Spek helps to analyse your audio files by showing their spectrogram.
RapScript - RapScript is the fastest-growing word-machine that is specially designed for freestyle rappers.
SoX - Sound eXchange is a command line utility that can convert various formats of computer audio files...
The Art of Rap - The Art of Rap is a free to use mobile application that allows you to create and record your rap movies to share it with others.