Audacity is a free software, cross-platform digital audio editor and recording application. It is available for Windows, Mac-OS-X, Linux and BSD. wikipedia.org

Mastering, a form of audio post-production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master); the source from which all copies will be produced (via methods such as pressing, duplication or replication). wikipedia.org

Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves, sound design, sound editing, audio mixing, and the addition of effects. wikipedia.org

Logic Pro is a hybrid 32 / 64 bit digital audio workstation and MIDI sequencer software application for the Mac OS X platform. wikipedia.org

A record producer is an individual working within the music industry, whose job is to oversee and manage the recording (i.e. "production") of an artist's music.

An audio engineer is a specialist in a skilled trade that deals with the use of machinery and equipment for the recording, mixing and reproduction of sounds. wikipedia.org

An arrangement of a musical composition is a reworking of a piece of music so that it can be played by a different instrument or combination of instruments from the original. wikipedia.org

Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves, sound design, sound editing, audio mixing, and the addition of effects. wikipedia.org

Audio restoration is a generalized term for the process of removing imperfections (such as hiss, crackle, noise, and buzz) from sound recordings. wikipedia.org

Audio editing is the process of taking recorded sound and changing it directly on the recording medium (analog) or in RAM (digital). wikipedia.org