A lot of musicians don’t get their audio mastered because they don’t see the importance or don’t think that they can afford it. It’s much more affordable than you likely think (more on this later) but right now let’s cover 3 substantial advantages of mastered audio over audio which is not mastered.
Quality Improvement – Most notably, getting mastered audio means that you’re improving the audio/final mix which you or your producer created. There are a lot of effects both analog and digital which the audio mastering engineer can make use of to improve the quality of the audio overall.
For example, equalization is used to boost particular ranges of the mix to give it a clearer/less dampened sound without going too far. Equalization can even be used to correct errors in the audio which went unnoticed in the mixing stage, so not that it’s ideal but the engineer does have that ability.
Reverberation is used to give a mix more atmosphere and to correct a “flat” sounding record. Compression is used to ensure that the track is completely in unity with itself while not sacrificing the dynamics created in the track itself. It obviously helps to get a skilled and experienced engineer to produce your mastered audio for you who knows how to use these effects effectively.
Second Opinion – Getting mastered audio means that you have a fresh set of ears giving you a fresh perspective on your mix. If you have a producer doing your mix for you or worse if you’re doing it yourself, whoever is in charge of it can have a difficult time distancing themselves from it after having been around it for so long. Therefore, it helps having that different perspective to determine what’s missing or wrong in the mix so that they can master accordingly.
Levels – The levels of your final mix likely won’t be on par with contemporary records of the day and will likely be much quieter than a track from another artist. The problem with this is that anyone listening to your music in a mix will have to adjust their volume accordingly when your track comes on in the mix as it’s likely much quieter than any other professional record they’re listening to.
This also comes into play if you want your record played on the radio as it needs to be comparable with other records they are playing. A mastering engineer knows how to boost the volume of a track (typically through other changes which they are making) to make sure that it’s on point with other current records.