Adventures In Audio

How much difference does mastering really make? (With audio)

by David Mellor

If your mix is as good as you can get it, can mastering really make all that much difference?

I have two quick examples of mastering, with comparisons of the original mix, the finished master, and the master compared with the mix at the same level.

The examples are snippets from Computer Music magazine's November 2016 issue where you can access full versions of the tracks and also watch a detailed video of the mastering process at the famous Metropolis Mastering studio in London.

Example 1

Let's kick off with a snippet of the first original mix (from Fantasy by Aristocrats)...

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It doesn't sound bad at all - the mix seems entirely appropriate for the genre of music. If you're curious, the level of this snippet measures -11.3 LUFS (I wrote about LUFS quite recently, and it is becoming an increasingly important topic). The level is louder than the original because I normalized it to 0 dBFS, which makes it the loudest it can be without specialized mastering techniques, and without changing any aspect of the audio other than the level.

And now the mastered version of the same section...

Phew! It's quite a bit louder. But as of now, that is considered to be one of the functions of mastering - to make the track louder, hopefully without affecting the audio quality too much. The level, by the way, is -6.9 LUFS, which is indeed pretty loud.

But other than loudness, has the mastering process really made the sound better? Here is the mastered version brought down in level to match the LUFS value of the original...

I recommend that you swap backwards and forwards between the original and the level-adjusted master, so you can tune your ears into the differences. At first you might not hear much, but I can guarantee you that the mastering engineer (Stuart Hawkes) has heard a lot more detail in this music than the average non-technical listener will ever appreciate. Listen again until you hear those details.

If I were to pick out one detail that is significantly improved, even at the same level, it is the way the kick drum integrates into the mix. Really this should have been done during the mixing stage, but the wizardry of the mastering engineer has been able to provide a magical improvement with access only to the stereo mix.

Example 2

Here is another example (Dubplate Sound by Computer Music magazine), once again from the November 2016 issue of Computer Music magazine, where you can hear this material in very much more detail. Here is a clip of the original mix, normalized to 0 dBFS so it is as loud as it can be without mastering...

The mix is refreshingly dynamic with a level of -15.4 LUFS, which corresponds well to the -16 LUFS that seems possibly to be the coming standard. And the master...

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Once again this is significantly louder at -9 LUFS. Clearly it is louder, but is it better? To find out, once again we look at the mastered version brought down in level to match the original mix...

This time I feel that the main benefit has been to bring up the lower-level sounds and ambiences that are present in the mix, but don't make themselves felt. This of course is what always happens in compression or limiting, so the mix engineer could have done this. Also, the snare drum has a more processed kind of texture, which some might say is contrary to the spirit of the genre, while others might say it brings the sound right up to date into the 21st century. It's a point to debate perhaps.


While the increase in subjective loudness created in the mastering process might be superficially impressive, even when the mix and master are played at the same level there are definite improvements in the masters. They may be harder to hear than level changes, but these subtle differences are the differences that take a recording and turn it into a 'record'.

P.S. In the spirit of a review, I'll add that I enjoyed Computer Music's coverage of the mastering process. Neither I nor anyone here has any connection with either the magazine or Metropolis Mastering.

Monday October 10, 2016

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David Mellor

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of Adventures In Audio.

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