It’s hard to describe mastering without quickly getting into some heady technical details that, if you’re not really interested in that sort of stuff, can feel a lot like watching paint dry.

Basically, it’s the final process of changes made to a song or group of songs before they’re released. This might include small changes to level or “volume”, equalization, dynamics, and other aspects of the sound field to give a song or collection of songs a glued together, polished feeling. I’ve heard it explained like this: The artist and mix engineer make strokes on the canvas, the mastering engineer picks out the frame.

Mastering also prepares the project for release on different mediums. A master for CD has different requirements from a master for a vinyl release, which is different still from a release on digital streaming.

Most importantly, a mastering engineer is a set of trusted, objective ears who is hearing your project for the first time. Often, the people involved in the process of creating a song have listened to it many, many times. We’ve all been to that point during a mix where you say to yourself, “I’ve listened to this 500 times, my perspective of this track is absolutely tainted.” With a fresh set of ears, a mastering engineer makes sure your project is free from sonic problems or inconsistencies before it gets released. You may know your plane and how to fly it, but it’s always good to get cleared for take off from the tower, right? A mastering engineer provides that peace of mind.