The mastering engineer is the last in a long chain of professionals who can creatively change and improve the quality of your music. They look at the overall 'picture' of the music, and they use lots of different mastering tools to process and fine-tune what they hear to try to improve what they're listening to.
The sound of the finished product rests solely with them, so they have to be very careful and very accurate with everything they do in the mastering studio - the finished version will be the one going to the manufacturing plant for mass reproduction.
No two pieces of music will ever the be the same, so each mastering project has to be approached on its own merit. Building up the experience it takes to become a mastering engineer can take years - one of the reasons why successful engineers can be so in-demand.
It's natural for the artist and the producer to feel very close to the music that they're creating. The producer will have a very good idea of what the finished versions should sound like, so they'll usually be in contact with the mastering engineer to help give advice on the sound's direction. The producer will often be in the studio with the engineer as well during mastering.
You'll also find producers sending pre-mixes to the mastering house during certain stages of mixing, to get feedback on potential areas to improve that will help deliver great mastering results.
Being able to interpret other people's ideas on how their music should sound is a vital skill to have for the engineer. To achieve this, there are a few core jobs in the mastering studio that must be taken care of:
Here's a typical and common workflow for a mastering engineer:
It's also important for a mastering engineer to be well-rounded in lots of different aspects of music:
Regular comparisons will often be made between the mastered and unmastered sound. This helps in instantly answering the fundamental question that's key to mastering - does it sound better?
Accurate records and logs are always kept of all the settings used on the studio's hardware devices, and of course all software settings are stored inside the studio's computer system. This is just in case anything goes wrong or if any tweaks need to be made at a later date - it doesn't happen often, but the safety net is important.
One of the main technical areas that needs to be looked at is the production of PQ codes. PQ codes are where all the information is kept for the tracks on a CD or DVD, for things like song lengths, song interval lengths, and any text information.
Just like modern-day recording studios, mastering studios these days will use a combination of hardware and software. High-quality analog-to-digital (A/D) and digital-to-analog (D/A) converters will be used to handle the changes between each hardware-to-software connection.
Software processing is usually centered around a DAW that's specially designed for mastering. Three of the biggest names are:
These DAWs differ from recording studio programs (like Pro Tools and Cubase) in a few key ways - PQ coding being one of them. They'll include all the technical features needed for completing a mastering job, but will also have other common DAW properties like EQ and automation.
Once the music has been mastered and everyone is happy with the result, a QC engineer at the mastering house will listen and check the music for any audible noises, clicks, or pops - anything that shouldn't be there. They'll also check other key features like track order as well.
The physical media will also be checked for errors. Manufacturing plants won't except CDs when the error count goes over a certain amount - different plants often have different standards, too.
In very simple terms, the engineer's job is to improve the sound of the music they receive from the recording studio. Their job isn't to make it sound 'louder' (although that's usually one of the most noticeable changes), but to make it sound 'better'.
Making something sound 'better' is naturally subjective, but when you hear the work of a skilled mastering engineer it becomes obvious straight away just how important their job is to the world of music.