What is a Mastering Engineer?

I was recently asked by MPEG (Music Producer & Engineers’ Guild of Australia) to write a simple and concise defintion of a mastering engineer. Here’s what I came up with;

A Mastering Engineer is the skilled professional responsible for refining & enhancing the sound of a mix, to ensure it sounds as good as possible across all playback systems. 

This stage of production referred to as ‘mastering’, is generally carried out in a purpose built mastering studio which is fitted out with very hi-grade monitoring and acoustic treatment. A Mastering Engineer is required to have a thorough understanding of audio, musical styles, and technical expertise with various audio processing tools. A mastering engineer uses their trained ears and technical knowledge to make critical decisions that enhances the mix while preserving the artist’s intent. Unlike mixing, where the engineer is manipulating all the individual parts, a mastering engineer is focused on the mix as a ‘whole’.
The mastering engineer’s primary goal is to refine and elevate the sound of a mix to its highest sonic potential. This process involves various tasks including:

1. Equalisation (EQ)
An Equaliser is arguably the most important processor in the mastering engineer’s tool box. It is used to fine-tune the frequency response of a mix, enhancing clarity and eliminating muddy or harsh frequencies.The final result of equalisation should produce a more detailed, engaging and pleasant sounding mix.

2. Levels & Dynamics
Mastering engineers carefully listen to the mixed tracks, balancing levels between songs on an album to establish a cohesive feel to a recording. Compression can also assist in controlling a mix that is overly dynamic or needs to be tighter in certain areas.
The careful use of compression on a mix can add energy and excitement as well as control specific frequency ranges that might be overbearing.

3. Sequencing and Track Gaps
The mastering engineer organizes the tracks in the correct running order, setting appropriate gaps between songs. A mastering engineer does this by feel, and is able to establish just the right amount of time between songs to enhance the sense of journey that artists want to achieve with any body of work.

4. Quality Control
The mastering engineer meticulously reviews the audio for any imperfections, ensuring a flawless listening experience. Preparing the audio for digital distribution or physical replication can involve listening to multiple sets of the same master destined for different platforms, such as; – Streaming Services (where different platforms can specify different standards) – Vinyl masters – DDP masters (Created for CD replication, this stage may also see the mastering engineer embed ISRC codes, track names, release title etc) Mastering engineers may also be called upon to listen to & approve physical ‘Test Pressings’ from vinyl plants. In this case not only is the mastering engineer listening for a faithful representation of his/her work, but is also listening for any physical anomalies that may have been introduced, such as loud clicks, pops or even ‘skips’ on the record.

Apart from the technical aspects, a crucial role of the mastering engineer is providing an unbiased and fresh perspective. They approach the music objectively, offering insights that can be missed by those deeply involved in the production process.  This outside perspective helps refine the music to its full potential.

At its core, a mastering engineer is there to create the best version of the mix possible. Understanding this vital role is crucial for all involved in music production, as it ensures that the final musical product will translate the artist’s vision across all mediums and platforms.