Mastering - Overview

Mastering is the art of taking one or more mixed recordings (more precisely, the mixed stems from multi-track recordings) and shaping the overall musical qualities to achieve the desired sound to be put on the finished album product (CD, vinyl, mp3, m4a, WAV, etc.).  Working with specialized audio gear and plug-in tools in digital audio workstations, a highly skilled mastering engineer with really good ears is usually tasked to do this.  Typically, in home recording studios, both mixing and mastering is done by the same person – the artist herself/himself.  Of course, this is not the ideal situation, as the artist is really “too close” to the music and lacks the objectivity (and frankly, the skill) to do the mastering.  A second set of ears, with critical listening experience, would be preferable. 
 
The goal of mastering is to achieve the desired overall balance in spectral tone, dynamics, and stereo imaging in each song and between all the songs in the album.  For an individual song, mastering offers a chance to fix up or tweak the balances that were set during the mixing process, and to bring up the volume to the desired sound level.  For a set of songs, mastering provides consistent sound balancing across the whole set, so that the album has a unified sonic character.
 
In my home studio, I rely on my PreSonus Studio One digital audio workstation (DAW) and the iZotope Ozone 9 Mastering software plug-ins to do the mastering.  The Ozone 9 plug-ins are inserted post fader in the Main Output stereo channels of the DAW, as shown here.

click on image to enlarge

The EQ, Imager, and Maximizer plug-ins are used for tonal, stereo, and volume balancing, respectively.  In the next three posts, I’ll review the function of each of these in the mastering process. 

---