Mastering is the final creative stage of the music production process. It is the art of crafting a collection of tracks into an audio album, a CD production master, a vinyl lacquer, or a completed demo.
Mastering begins with the final mixes from the recording stage and ends with a master file that is sent for distribution or duplication.
As mastering engineers we bring specialist skills and mastering equipment to this final stage.
Fresh ears can give a unique perspective of an entire mastering project, when everybody else is so focused in on the detail that they have lost sight of the overall context.
We create balanced and accurate listening environments where we can hear, and compensate for, any anomalies in the recording process.
Mastering engineers are specialists. We don't claim to be experts at recording or mixing because we have spent most of our careers mastering. For similar reasons, most recording engineers and producers prefer to pass their work on to a mastering engineer for the final stage.
The first thing a mastering engineer needs is a great sounding room.
In that room he will put some extraordinarily good speakers.
Acoustic treatment and high-quality monitoring are crucial to a good mastering studio. With a balanced, accurate listening environment, it is possible to hear exactly how a recording sounds, and make good judgments based on those observations.
Mastering engineers probably spend more time, money, sweat and tears on acoustics and monitoring than on any other aspect of a mastering facility.
Most high-end mastering engineers like to use good analogue equipment for a lot of the sound processing that they do. High caliber Analogue to Digital and Digital to Analogue converters are therefore essential to ensure that the conversion between the analogue and digital domains is as accurate and real as possible.
Listening tests prove time and again that there are big differences in quality between different converters, and so as mastering engineers we choose our converters very carefully and select only the best.
Applying compression when mastering reduces the dynamic range of the signal being processed. This involves making louder sounds quieter, and conversely, once you have applied a make-up gain, making quieter sounds louder.
Applying compression to an entire mix is very different to compressing individual instruments, as you might during the recording process. When mixing, for example, you might compress a lead vocal heavily to make sure that it is at a constant level and always cuts through the mix.
During the audio mastering process, however, we are applying a compressor to the whole mix: some sounds will be triggering the compressor, but all sounds will be affected by it.
Used clumsily, compression can flatten, distort, muddy and strangle your music.
Used judiciously, compression can add punch, clarity, drive and feeling to your music.
Usually called EQ, equalisation applies gain to a certain frequency while leaving others unchanged.
Mastering engineers use EQs to change the spectral balance of the music, in other words, to boost or cut various low, mid and high frequency ranges.
Mastering engineers use EQ for a number of reasons when mastering:
- to compensate for anomalies in the listening environment it was mixed in;
- to bring clarity to vocals, guitars, snare, horns and other mid-range;
- to clear up a muddy bass, to add punch to a kick drum, to sparkle the cymbals;
- to make all the tracks in a project sound balanced next to each other.
Once again, EQ used badly can destroy, EQ used judiciously can transform.
Levelling is one of the most powerful and often overlooked tools in a mastering engineer's arsenal.
Setting the relative levels or volumes of each track within a project is one of the mastering engineer's most important tasks. An album must have a consistent volume with quieter songs sitting naturally alongside louder songs - it should play all the way through without the need to adjust the volume.
The mastering engineer's ears will be the final judge of the loudness of a track. We will use different meters for reference, all with different meter ballistics and meter rules. All these will help, but the final judgment must be that of our ears.
A limiter is used to reduce the level of the highest peaks in an audio signal.
We use limiters to raise the perceived level of sound without creating over levels. Once the mastering engineer has balanced the relative levels of your tracks, we will use a limiter to raise the loudness of the music to the optimum level. Once again, delicacy is required to achieve the required level without causing distortion. See the note 'On Loudness' for further discussion of levels and limiting in the mastering process.
Once the mastering work is complete, we will then create master files in the correct format for delivery.
This may be WAVs at any resolution needed, Apple Digital Master files (formerly Mastered for iTunes), a more dynamic WAV for YouTube, a DDP for CD Replication, high resolution WAVs for vinyl etc.
If you need a format not mentioned here please contact us, we have probably done it before!
To keep up with demand for songs to be louder and louder, mastering engineers have been relying more and more on compressors and limiters to coax the loudest levels out of a given audio format. In the days of vinyl records the pressure was to get the loudest cut onto the lacquer, and radio stations have always vied to be 'the loudest station on the dial'. These days, the same competition for loudness is happening in digital formats.
Any digital format has a finite limit to the loudness of a signal recorded onto it. In order to make a song sound louder, the music must be pushed closer and closer to that maximum level using compressors and limiters. Before compression or limiting, a piece of music may have dynamics - quiet parts, medium parts, loud parts and very loud parts. The louder you want your song to be, the more you must take away from those dynamics. What is often left at the end of this process is all the elements of the music forced to be as loud as is possible. Whilst this can make a track sound punchy, hard and powerful, it can also make the music fatiguing to the human ear, which misses the variety of dynamics.
Now that most streaming platforms have implemented some kind of Loudness Normalisation, the advantages of mastering a song with all its dynamics intact are back! If you upload a super loud master to YouTube, Apple or Spotify it will get turned down on playback. A quieter master will get turned down less, if at all, and so will sound -better- than a super loud master.
Of course, if loudness is the most important factor to you, a good mastering engineer will use all the tricks he knows to apply the maximum boost to your music. Please consider, however, the advantages of leaving some dynamic range in your finished masters. Your music will sound more natural, more expressive and more real.