The process of mastering audio has really evolved since its start as part of vinyl record production. Not to mention on-demand digital streaming services like Youtube, Netflix, and Hulu, have blurred the lines considerably on what defines “professional” mastered audio for sync.
But what is mastering, anyway? How does a modern-day master differ from a final mix, and in the age of streaming and digital delivery, does it even matter?
The short answer is yes — we’ll explain why.
What is Mastering?
In short, mastering is the process of taking a finished audio mix and making it ready for release, and/or duplication. This involves:
- Using audio software and/or hardware to adjust a variety of sonic qualities on a project’s final mix.
- Ensuring it sounds the best it possibly can, regardless of where it’s played (on earbuds, smartphone speakers, home stereos, you get it.)
Think of the last time you were watching a YouTube video and nearly jumped out of your skin from a blaring advertisement. Or maybe you maxed out the volume on a movie, trying to hear seemingly muted character dialog, only to get slammed with bass effects a moment later.
Mastering could’ve helped smooth out the ride.
Proper mastering gives you the ability to address these problems without having to return to the mixing stage. Better yet, it adds a level of polish that makes professional audio sound finished. While the tradition of audio mastering comes primarily from the world of music recording, the principles discussed here apply just as well to the mastering of:
- Dialog
- SFX
- Musical score elements applied to trailers, movies, video games, and TV shows
Mastering vs. Mixing
Mastering does come with some limitations when compared to mixing. Notably, mastering engineers typically only work with a single stereo or surround sound audio file per project, as opposed to the stems, dialog or instrumental multitrack usually delivered to mixers.
The Drawbacks
As a result, mastering engineers have far less control than mixers over the balance of individual instruments or dialog elements in a track. It wouldn’t make sense, for example, to ask a mastering engineer to mute or remove an element in a mix, or to turn up the volume of an instrument in relation to another. These adjustments must be made in the mix, where the mixer can access the tones and decibel volumes for each sound individually.
The Benefits
The silver lining to this limitation: mastering engineers can focus on big-picture problems that weren’t caught in the mixing stage. This may cover:
- Broad-level adjustments to particular frequency bands (think low bass rumbles or the sparkle of the high end frequencies)
- Adjustments to overall loudness or dynamic range of the audio (as in the case of our YouTube example)
The perceived loudness of individual instruments or elements may change slightly over the course of these adjustments. In cases where returning to the mixing phase is not an option, you may need to address balance issues in the master. In general it’s best to use mastering as the final polish on a finished mix, as opposed to expecting it to change the basic construction of the audio.
Making Audio Competitive
A finished master should sound bigger, brighter, more natural, and more professional than before. You’ve prepared the audio to compete well against other media in playback.
With music sync, a good master won’t unnecessarily hog key audio frequencies. This means it can integrate with dialog or SFX elements with relative ease while maintaining high sound quality. Many mastering houses will intentionally master their production music loud with the understanding that it will eventually get turned down in the final dub and must still be audible. If you find that instrumental elements are disappearing while turning down the volume of a music cue, it may be a sign that a track has been mastered too low or with too great a dynamic range.
While many attribute mastering solely to loudness, the process of mastering encompasses everything that can be produced on a final mix to help it perform competitively against the works of contemporaries. It’s not uncommon for mastering houses to accept Reference Tracks from clients that serve as targets for loudness, compression, and overall desired aesthetic quality.
This constant attentiveness to the end product, including the technical limitations that will affect the audibility of a composition as a whole, is what makes mastering an essential final step in audio production. Ultimately, it should help yield a finished product worth bringing into the world.
