Here are some possible definitions of mastering:
- Creating a production master for replication
- Achieving an optimal balance of tone and level
- Gaining the benefit of an experienced, impartial ear
- Top/tailing and sequencing
- Fixing any outstanding problems from a mix
- Making your music sound the best it can be
- Making it f-ing loud !
So, which one is right? Well, all of them, to varying degrees - except the last one. My favourite explanation is this one:
Mastering is the art of making a collection of tracks into an album (*)
(*) or single, or compilation, or podcast, or catalogue...
This is achieved by one or more of several techniques. As well as technical tasks like ensuring the best transfer from the source and creation of a suitable master, these may include:
- Level adjustments, often using a limiter or compressor
- Equalisation (EQ) to achieve a natural, balanced sound - broadly speaking the right amount of bass and treble, but also much more detailed adjustments, for example to remove unnatural resonance or build-up at certain frequencies, or perceptually improve limitations of the mix. Common examples might include adding "air", or "punch", or adding "edge" to guitars, for example
- Correction of faults - for example removal of clicks, pops or thumps, buzz, hum etc.
- Detailed sound restoration - usually only necessary on "vintage" sources, can include removal of vinyl clicks, hiss & distortion etc.
- Stereo image adjustments - this is less common, but may involve widening the stereo image, or (occasionally) adding reverb
Exactly which of these is needed varies from album to album, and even track to track. Some jobs need major surgery, a very few I've ended copying flat from the source. In the later case, did I actually master them? Yes - because I listened carefully, in a dedicated studio using exceptional monitoring, and used my ears and experience to determine that nothing extra was needed. (Actually, more often than not we can spot a source this good within a few minutes of beginning to listen, in which case we contact the artist and offer them the chance of a Direct Transfer instead, so they don't pay for something they don't need.) Deciding to do nothing at all on one or two tracks is just as valid a mastering decision as any other.
However there is still lots of room for confusion and debate. Should mastering engineers:
- Use the minimum possible processing, and keep everything as close as possible to the original material
- Preserve the artist's original vision
- Pull out all the stops to transform a source into what it always "should have been"
- Preserve the original's dynamic range and impact
- Use EQ and compression to achieve major increases in level
- Make everything fit their "trademark sound" ?
Once again my answer is "all of the above" except the last one. This may seem contradictory - surely some of them are in direct opposition to each other ? Not really - because an element of the mastering engineer's skill-set which doesn't often get talked about is intuition. With almost every source I play, I can hear where the artist or engineer was "trying to get" within minutes or seconds. I can hear what they're trying to achieve, and I see my job as trying to help them get there. Using minimal processing, if possible but if not by throwing the kitchen sink at it, and all combinations in between - always staying true to the original mix.
The issue of levels and compression is a good example of this - there are lots of easily available limiter and compressor plugins now, but many of people complain that they ruin the sound. Mastering engineers use very similar tools to achieve their results, and claim that they make things sound better. How can both be true? Partly because there is still a distinction between the tools - mastering studios typically spend thousands of pounds on a single compressor, whereas for the same money you can buy an entire suite of plugins - but also because we are constantly honing our skills to use the tools transparently, and our listening environment to be able to hear when it's working. To some extent, the skill of a mastering engineer is to achieve an appropriate level for every track , sometimes reducing the dynamic range in the process, but make it sound as if the final result is actually more dynamic. Or to make major EQ adjustments, without changing the essential qualities of the original.
So, you might ask - what's the point of paying for something that can be so subtle ? There are several answers to this:
- Often it's not that subtle ! If I'm doing my job, the mastered version will simply be better than the original, while retaining everything that was good about it.
- Where the difference is less obvious, it will only be difficult to hear when level-matched. The importance of increasing the level of a track to it's own particular "sweet spot", without pushing it over the top, is hard to over-emphasise. Doing this for all of the tracks in an album, and getting them balanced perfectly against each other in their final sequence is even more important and valuable. This needs to be done with great care and skill though - it's almost impossible to achieve this simply by pushing the level up into a plugin.
- Ideally, the differences should be subtle. A truly great mix only needs the slightest of tweaks, but even these minor adjustments, over the course of a whole album, add up until the sum is greater than the parts.
As I type this I'm struck again by the inherent contradictions of the job. It requires you to be entirely humble - I start every session by listening carefully to the source and thinking "what's good about this ?"; but also supremely arrogant, making changes to a mix that someone has sweated blood over for perhaps weeks or months. It requires deep technical knowledge, but many of the judgements made are largely aesthetic and artistic. It means knowing when something ain't broke and not trying to fix it, but also knowing when to roll up your sleeves and get your hands dirty...
What is mastering ? Has this post helped explain it at all ? Who knows...