What is mastering and why do I need it?

Mastering is the bridge between the last creative and artistic part of the music creation process and the less exciting but highly important technical and quality control aspects. The science. It’s the last chance to make sure all the songs of a project sound as good as possible, and also work well together as a group. Once the mastering is approved, the mastering engineer also creates a myriad of master formats to be used for digital distribution (Apple Music/iTunes, Spotify, Amazon HD, TIDAL etc.) and production of physical products such as CDs, vinyl, and cassettes. Metadata and CD-Text entry can also be critical.

You may need up to 4 (or more) different master formats (CD, digital distribution, vinyl, mp3 for reference and download codes) to be created and checked for quality assurance. Digital distribution needs are changing day by day as well, and may require more than one master format to optimize for all possible digital distribution options.

Mastering is more than just stereo bus processing, it’s also quality control.

How is mastering different than mixing?

With traditional mastering, we are working from a stereo mix which is only two channels (left and right). This means that changing the sound of one particular instrument or element without affecting other instruments or elements of the song is usually not possible. If the bass guitar needs to have more low end, doing this in mastering may also cause the bass drum to become too boomy. Mixing is where you have proper isolation and control of each instrument or element and are able to freely control individual instruments or elements of a song by changing their levels, shaping their tone, and adding effects such as reverb and delay if needed. The more happy you are with your mixes, the more happy you will be with the mastering. Don’t rely on the mastering process to make or break the sound of your project. The mastering process should ideally enhance and compliment what is already there, and give the songs cohesion so you can listen from start to finish without the urge to adjust the settings, level (aka volume), or EQ on your playback system.

Why can’t my mixing engineer just master my project too?

There are a lot of technical details involved in creating a distribution and production ready master for the variety of master formats used today. It’s important to listen to the audio with extreme attention to detail, and use software tools designed specifically for mastering which can act as an audio microscope to be sure there are no unwanted noises, clicks, pop, or other anomalies hiding in the audio. These things are easy to overlook in a mixing studio environment. Mastering studios are designed to be very quiet, transparent, and neutral sounding spaces with a very clear and accurate playback system. This makes it easy to detect any issues or potential issues, and to be confident when making EQ and other decisions regarding changes to the audio.

Mixing and mastering are two very different processes and it’s easy to overlook something during the mixing process that can still be addressed in a mastering session. With mixing, you may be working with dozens and dozens of audio tracks.

Mastering is more of a global approach. Using high quality headphones, I scan every second of the audio for potential glitches or unwanted noises that have gone undetected thus far for whatever reason. Also, because we often raise the average loudness quite a bit in the mastering process, sometimes these issues can be become more audible after the mastering process and then need to be addressed by the mastering engineer.

With recording, mixing, and production you’re looking at the trees, in mastering you’re looking at the forest.

Mastering is more than just stereo bus processing, it’s also quality control.