What Is Audio Mastering and How Has It’s Role Changed?

What is Audio Mastering, And How Has It’s Role Changed?

This is a guest post from mastering engineer Barry Gardner, the sole mastering engineer at SafeandSound Audio Mastering

Audio mastering is seen as a bit of a dark art or mysterious in nature, the reality could not be further from the truth. It seems to get this rumor attached to it because of a number of factors.

Why does mastering seem mysterious?

1) The use of esoteric and rather expensive audio equipment.

2) The techniques used are very specialized.

3) The techniques used are an accumulation of decades of training and professional experience.

These are a combination of factors that are not always easily achievable so they tend to remain elusive and possibly a little mysterious. The reality is that a audio mastering studio is a very finely tuned environment, loudspeakers that go from 20Hz to 20kHz with exceptionally low distortion, very high quality and clear DA and AD conversion, very accurate and true acoustics and a set of ears that provide both objectivity and experience. When you couple these exacting details the end result can appear difficult to attain.

However the results are environment and experience lead, the environment is tuned for accuracy and detail and the engineer has usually been working in audio for decades. It is only when you can hear the details with enough accuracy that you can hear what needs to A) be corrected or B) can be enhanced.

A few words about expensive analog equipment:

Audio mastering can be performed with plug ins this is a fact and so long as the monitoring environment is very accurate and full range good results can be achieved. Expensive analog equipment can subjectively improve on digital counterparts, analog equipment has circuitry which is almost alive and very difficult to emulate to perfection.

The traits of analog equipment usually go beyond their intended design purpose. i.e. the equalizer that has a slight effect on the stereo image, a compressor which has a ratio control that affects the high frequencies, an eq which softens transients or a compressor which thickens the low frequencies. As you can see analog often brings something euphonic and unique to the processing which is very difficult to find elsewhere. So whilst plug ins can do the job, no compromise professional mastering happens with a combination of analog and digital equipment. This serves the clients project best and provides the widest and best options for enhancing the music.

What is mastering ?

Audio mastering from a historical perspective is nothing more than an engineer who ensures that a music mix successfully transferred to a storage medium which is capable of producing replicated or duplicated copies. A vinyl lathe engineer must ensure that the audio adheres to very specific standards otherwise the disk cutting process will simply fail. It is a mechanical procedure which must be set up to exacting standards.

Historically there are of course other formats such as cassette tapes which had a rather restricted dynamic range so the music was mastered in such a way that it would work with the release medium. This is much the same today, we see a resurgence of vinyl releases and of course we have CD, .wav or .aiff, MP3 and AAC files. So there is a purely technical element related to mastering.

The changing role of audio mastering:

Over the last 15 years the music industry has seen some radical changes in the way music is recorded, consumed and distributed. Many thousands of producers work from home creating their musical productions from the comfort of their own houses (and less time pressured). This is a fundamental shift in how much of the music released is produced, written and engineered.

In many instances files are now sold and distributed online and many people now listen to music on many more types of device, iPads, MP3 players, laptops, notebooks, ear buds, mobile phones and of course the more traditional car stereo and home stereo systems.

These changes have also had an effect on the audio recording and production chain of events. It is absolutely great that people have the freedom to create music at home on their computer systems, however many of those making such recordings have not had formal sound engineering training or experience.

This has meant that the standard of many recordings has sadly dropped. It stands to reason that a musician cannot always be extremely free and musically creative and be a professionally trained sound engineer at the same time. So there is sometimes some room for improvement when it comes to recording and mix techniques.

One misunderstood view is that a recording or mix can be taken to a state where it’s ‘good enough’ and then the mastering engineer can do the rest. Wrong. Good mastering relies on good mixing. Mastering is by it’s very definition somewhat restricted in what it can achieve, it uses stereo 2 track interleaved files and all the processing is performed on this sole file. This means whilst great improvements can be made it can only go so far. A mastering engineer cannot push the snare down 3dB or de-ess the lead vocal without affecting the snare or high hats etc. So the mastering still relies on a competent mix down.

My own personal experience is that people very much appreciate a mix appraisal if they find themselves in this position. It can be good for both engineer and client to iron out any mixing issues before the track is mastered. Mastering engineers are split over this and many wish just to master the track and get on with it. I cannot personally see any problems with offering some advice which produces a better end result (if asked of course). The general view is that if you are a confident mix engineer you will not request a mix appraisal and for some who are maybe not as well versed in mixing a helping hand can be very useful. Not everyone is willing to put in some extra time to assist people who are finding their feet in the audio production world.

A few words of caution:

Because some people have misunderstood what audio mastering is they have decided to set up websites and masquerade as mastering engineers. What you will find on these sites is no pictures of audio equipment in situ, no clients list, no engineering back ground, text and graphics only and very little in the way of professional audio engineering experience. Do ensure diligence when you seek online mastering services on the internet.

The general goals of audio mastering :

1) Correct tonal problems that hinder good translation of the music to all systems.

2) Subjectively enhance the music using specialized tools and experienced hearing.

3) Produce a perceived volume which best serves the music and/or clients desires.

4) Ensure the master is click, bad edit, pop, hiss and rumble free. (quality control)

5) Sequence the music with musically sympathetic spacing.

6) Ensure the master format is error free and tested ready for duplication.

7) Provide a technical point of contact for the pressing or duplication plant.

8) Ensure fades, intros and outros are tastefully applied.

9) Insert meta data such as track names, artist names and ISRC codes.


Mastering has changed and it is much more than making tracks loud, it is essentially the last objective quality control process before music is released into the distribution chain. A good mastering engineer can add up to a 20pct increase in perceived subjective quality to a musical project before it is released as well as ensure it all works technically.

These days mastering covers wider ground than ever before in the production chain of events, whilst it still serves the very job it was designed to do many years ago it is so much more and has extended itself and become even more relevant in todays music and recording industry.


Note from 2infamouz:
Barry Gardner is a reputable and experienced mastering engineer, and we highly recommend you visit his website if you need an album or other audio project mastered. You can visit his site at SafeandSound Audio Mastering.


February 3, 2013 Audio Mastering No Comments

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