Mastering

Mastering is regarded by many as some kind of dark art. But it’s basically the general term for the final stage(s) in preparing a mix for release, either in digital or physical format. Some would say getting it ‘radio-ready’.

My approach to mastering:

If am working on a mix from the start, I will work with the mastering stages in mind, and any previews will be sent at approximately the expected loudness of the final master. So there shouldn’t usually be a need for a drastic change in the quality or loudness of the mix by the time we approach the mastering stages.

But sometimes there’s an opportunity to add some extra excitement or flavour. In addition, an album consisting of tracks of different styles, sonic palettes or intensities may sometimes need a bit of balancing out at the end to get the tracks to flow seamlessly into one another. The idea is to make any necessary adjustments at this stage super subtle. It certainly shouldn’t sound like a remix! 

But if you just want me to mix…

You may prefer to employ me to work solely on the mix and have the mastering done by a separate mastering engineer. That’s totally fine – it’s sometimes a good idea to get an objective perspective at the end of a long mixing project (hence why I would normally set aside at least a few days rest between finishing the mix and beginning mastering, should deadlines allow). If this is the case, there are a handful of mastering engineers I would be more than happy to recommend.

Or just do the mastering…

I also offer mastering on premixed material. All I require are the final wavs/ aiffs/ other lossless format of your tracks.

What about stem mastering?

If you have mixed your music yourself, and you are basically happy with the sound and balance of the different instrument groups, but there are some issues with the EQ or dynamics that you are struggling to fix, I also offer stem mastering. This involves bouncing your tracks down to a limited number of groups (e.g. vocals, guitars, drums) as single stems. This means any issues specific to particular instruments can be addressed individually without significantly affecting the mix as a whole.


So what does mastering involve?


It can loosely be broken down into two main stages: artistic mastering and technical mastering.

Artistic Mastering:

Artistic mastering focuses on three aspects of the mix:

  • frequency balance;
  • dynamics;
  • loudness.

Frequency balance:

Care must be taken to ensure that the frequency response of the music is evenly balanced, and that there is no excess or deficit in any particular frequency area. Ideally, this will have been addressed during the mix, but if the mix has been performed in suboptimal listening conditions (e.g. an untreated room, cheap headphones etc), the mixing engineer may have inadvertently added or taken away too much energy in certain parts of the frequency spectrum. This can lead to mixes sounded either too ‘bloated’ or too ‘thin’ when played back on other systems. Or there may simply be some narrow frequency band that sticks out in the high (e.g. ‘harshness‘) or low (e.g. ‘rumble‘) registers that wasn’t detected the first time round.

Issues such as these can be corrected in the mastering process. This ensures that the mix sounds both rich and balanced regardless of the listening system or environment (what is known as translation).

Analysing the frequency spectrum of a mix during mastering.
Analysing the frequency spectrum of a mix. This mix is fairly balanced, though maybe the areas around 100Hz and 400Hz need looking at.

Dynamics:

By dynamics, I’m referring to the contrast in volume between loud and quiet sections. Having this contrast in levels between or within passages of music adds interest and excitement. A mix lacking dynamics might be tedious to listen to. However, it’s important to ensure a mix isn’t too dynamic, so that the listener does not need to adjust the level of the music as they listen.

Mastering can help bring dynamics under control, so that they are relatively consistent, without being too static. However, it cannot add dynamics to an already heavily compressed mixed. For this reason, any master buss (stereo output) compression or limiting on the whole mix should ideally be removed before the mastering process.

Loudness:

Loudness is an interesting topic, and one that many of my clients seem preoccupied with, so I will go into this one in a bit more detail.

Monitoring the loudness of a mix during mastering.
Monitoring loudness.

It is important to ensure the overall loudness of each song, and the loudness relationship between consecutive songs (and even between different sections of the same song), is relatively consistent and adequate to be played alongside other commercially released material. No-one wants their track to be the quietest in a playlist, right?

The primary factor determining how we perceive the loudness of an audio source is something called the RMS (Root Mean Square). This is basically the average energy of a sound wave over time. A sound wave with a high RMS sounds loud!

It’s important to clarify that loudness is actually something that is intrinsic to a mix, and not just the result of how much we turn up our speakers. Loud mixes will sound louder than others when played at the same volume through the same set of speakers. This is because they contain a consistently higher intensity of audio information (the RMS) relative to other mixes. Certain genres of music require a certain degree of loudness to suit the style – e.g. extreme metal or EDM. It adds to the ‘intensity’ or ‘thickness’ of the sound.

So why not make the mix as loud as possible?

Increasing the overall loudness of a piece of music comes with a trade-off – a loss in dynamics (i.e. the difference in level between the loudest and quietest moments in a passage of music)! Music lacking dynamics tends to lack ‘excitement’, and furthermore, can be quite fatiguing to listen to over long periods.

So the key is to find the right balance between loudness and dynamics.

Thankfully, to take the guesswork out of how loud your music should be, the major streaming services such as Spotify, Apple Music, Amazon etc. now employ loudness standards. This means that a limit has been set as to how loud music will be played back when streamed, and so extra loud masters will be turned down to a certain level so that they do not jump out in a playlist, for example (though it should be noted that if your music is mastered below this level, it won’t get turned up to match everything else!). For more information about this, check out renowned mastering engineer Ian Shepherd’s blog.

The Loudness Penalty Meter used in the mastering process.
The Loudness Penalty Meter.

What about loudness on physical formats?

If you are planning to release your music physically, this standard does not apply. In the case of CDs, only the true peak level is important. This means there must be a limit (a ceiling) to the very loudest moments in your music to prevent digital clipping occurring (whereby information is lost in the transfer to the analog domain, resulting in an unpleasant audible distortion). But you can technically still crank the RMS until it starts to have a detrimental effect on the music.

With vinyl, the optimal level depends on a number of technical factors. But, to spare you the details, essentially a good CD master should make a good vinyl master! 🙂

So, how loud should your tracks be mastered? In the end, it really is a personal decision. I have mastered music for musicians who only intend to release their music digitally, yet who still want it mastered way louder than the loudness limits imposed on streaming services. This might seem counterproductive, but it’s not necessarily wrong to do this! It’s an artistic decision. Whether you prefer your music to be primarily dynamic, or primarily loud – the choice is yours!

I can only offer one piece of advice here. If you choose to boost the loudness of your mix in the mastering process, make sure you adjust the level of your master and play it alongside your original mix at the same volume. Does it sound better? Or just louder?

Technical Mastering:

Technical mastering is rather less exciting, but is nevertheless important. It involves the following processes:

  • Fixing or removing issues like hum or noise;
  • Finalising transitions between songs;
  • Adding metadata (such as track names, artist names, composers, ISRCs etc.)

ISRCs (International Standard Recording Codes) are specific ID tags added to a digital audio file so that whenever your music is played online or on the radio, royalties can be assigned to that song and collecting by the record label or relevant collecting society. Applying for ISRCs is free of charge. You can find out how to get them here.


If you’ve already mixed your music and would like me to master your mixes for you, just head on over to my contact form here. I’ll be happy to discuss your requirements. If you’d like me to mix your music from the start, you can head over here to read about my approach to mixing.