What is mastering?

At the end of a record production the mastering process is always applied, but what does this mean?

Published February 5, 2021, 12:00 am CDT

The process of producing songs or instrumental music involves many steps, if we arrange them in chronological order, it would look like this:


  • Composition
  • Layout
  • Recording
  • Mixture
  • Mastering

To better understand what mastering is, let's take a look at the basics.


It allows audio volume to be louder without distortion

This is mainly useful for broadcasting music on radio stations. If one song is suddenly louder than the other, it’s normal to pay more attention to it. This tactic is what’s popularly known as “volume warfare”, this results in masterizations that sacrifice quality over volume. This was the case of the popular band Metallica with its album Death Magnetic.


Here is a comparison video between the CD version and the Guitar Hero video game version. The only thing that changed was the mastering process.


 Metallica Death Magnetic "That Was Just Your Life" CD vs. Guitar Hero Comparison:   



Many experts believe that the biggest crime in the first version of the CD was the distortion of the audio at various times. When the record came out, this problem was so notorious that many fans (myself included) thought their CD player was broken.

Good mastering will never allow clipping, which is distortion of the audio due to too high volume, this makes the track sound bad.



Done correctly, it’ll give cohesion to the track, as it cuts the volume peaks and highlights the softer parts. Besides improving the sound cohesion of a song, compression is one of the main reasons why we can increase the volume of a track without causing clipping.


On discs, it leaves all tracks at the same volume

When creating a record production, it’s important to ensure that all the songs on the CD keep a consistent volume level to avoid an uncomfortable experience for the listener. Imagine what would happen if you had to adjust the volume for each song due to a disparity between the sound of each track, it’d be a disaster.


It also helps improve your stereo image

Another part polished during this process is what we call the "stereo image." This means that the audio’s spatiality will have a better distribution, which allows us to perceive an enveloping and massive sound. This process is evident in metal tracks.


 Mastered vs Unmastered Music with Jesse Cannon:



Polish and enhance mix details with equalization

Mastering enhances the details of a well-made mix by accentuating some missing frequencies or cutting excessive ones to add clarity. These are almost surgical operations, targeting very specific parts of the spectrum.


While mastering is never going to compose a bad mix, it can damage a good one if not careful.


Harmonic excitation

When we want to highlight a larger frequency area - for example, a section of the spectrum where some instruments resonate better - we use a "harmonic driver". This device or program will send a subtle distortion to the sound register we want to highlight. 


 Excitadores armónicos - Qué son, para qué y cómo usarlos:



Audio restoration

Small errors or clipping that the original audio may have come to light when you crank up the volume. Most of them can be adjusted using special programs that will correct those details with precision and without affecting the rest of the track.


Conversion to final format

Finally, the file is exported in the correct format for each platform. In the case of CDs, it’s in .wav files at 16 bits and 48 khz.


Basically, these are the processes that occur during the mastering stage, and in recent times the term Remastering has gained popularity.



As technology is constantly evolving and the quality of the tools increases, today’s equipment can breath new life into old recordings. Some remasters will sound more defined or up-to-date, but preserve the essence of the original sound as the mix remains unchanged.


It’s a process similar to that in the making of movies or video games, where the image quality is restored and converted to 4k, or the color quality is improved without necessarily modifying anything in the original recording.


Some remasters will be more subtle than others, but the ultimate goal of any remastering is to give a second life to original songs or works.


 METALLICA (original vs. remaster) Master of Puppets:



Check out our other articles to learn more about mixing, recording, and composing a track.


Do you have a remastered CD edition that you like better than the original album?


Share your opinions!





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