What is “music mastering” or “mastering audio” anyway, why do we do this?
Mastering for music recordings, is an extension of the mixing process by further adjusting the sound of the finished mix.
It’s other primary role is to produce the “parts” needed to release the music either for on-line & streaming distribution or for physical media releases (Hi-Res, vinyl, CD, cassette, thumb drive, etc).
Mastering exists mostly apart from mix process for a few key reasons:
A Mastering Specialist brings a trained ear and skills specific to the mastering process.
Mastering equipment has to be rigorously chosen, be it for clean tone or to sweeten the sound in just the right way. Poor equipment and settings can damage a good mix very easily if not careful.
Mastering studios are different listening environments from where the tracks were produced. In particular, often Hi-Fi listening systems are used to help hear more resolution and detail.
Perhaps the biggest benefit is having mastering expert “hear the mix” for the first time. It is so much easier to hear the sound of the recording and be able to address it’s needs if you have a fresh ear.
While many mix engineers could master the project, they often do not like to master their own work for the reasons above. After all the work of tracking, editing, mixing is done, it’s time to give the producer a break and pass it on to a mastering specialist!