Mastering & Low End
What is mastering, and what is a master?
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A master is the finished file the world hears. Mastering is the stage that turns your mix into that file.
It is the last creative and technical step before release, and it works on one thing only: the finished stereo mix. That single constraint explains most of what mastering can and cannot do.
What mastering actually involves
Five jobs, in roughly this order.
Tonal balance. Small, broad EQ moves so the track sounds right on every system. Not surgical work — a decibel here, a shelf there.
Dynamic control. Gentle compression, sometimes clipping, so the track holds together and feels solid rather than uneven.
Level and ceiling. Setting the final loudness and making sure nothing exceeds the ceiling. See how loud should your master be.
Technical safety. True peak, mono compatibility, DC offset, file format, sample rate, no clicks at the start or end.
Consistency. If the track is part of an EP or album, it should sit at the same perceived level and in the same tonal world as its neighbours.
That is the whole job. Notice how small each item is. Mastering is a series of small decisions applied carefully, not a transformation.
What a master file is
A single stereo file, at the delivery specification, ready to hand to a distributor.
In practice that means:
| Property | Typical delivery |
|---|---|
| Format | WAV or AIFF, uncompressed |
| Bit depth | 24-bit for delivery |
| Sample rate | The project’s rate, commonly 44.1 or 48 kHz |
| Peak ceiling | Slightly below full scale, for encoder safety |
| Length | Trimmed, with clean starts and ends |
If a platform asks for something specific, that specification wins over any general advice.
Why mastering cannot fix a mix
This is the part worth internalising.
Mastering works on the stereo file, where every element is already summed together. There is no vocal channel. There is no kick. There is one signal containing all of them.
So if the vocal is buried, you cannot raise the vocal — you can only raise the frequency range the vocal occupies, which raises the guitar, the snare and the synth in that range too. That is why mastering a broken balance produces a louder broken balance.
The full version of this decision is in fix it in the mix or the master.
What good mastering does that mixing does not
Distance. A fresh perspective on a track you have heard four hundred times. This is the single most valuable thing about mastering as a separate stage, even if you do it yourself a week later.
Whole-track thinking. Mixing is about relationships between parts. Mastering is about the track as one object, compared with other finished tracks.
Technical assurance. Someone actually checking that the file will not distort after encoding, will not collapse in mono, and meets the delivery requirements.
Consistency across a release. Nobody mixing individual songs is thinking about whether track three is 2 dB quieter than track four.
Mastering your own music
Entirely reasonable, with three disciplines:
- Leave time. Master on a different day. The gap is doing most of the work.
- Use references. Load two finished tracks you admire, level-match them, and compare. Without references, self-mastering drifts.
- Keep it small. If you find yourself making large moves, stop and go back to the mix. That is the mastering stage telling you something.
What to hand over
Whether to yourself later or to someone else:
- A stereo mix with headroom — a few decibels below the ceiling, no limiter on the master.
- No processing you are unsure about.
- The full-resolution file, not an MP3.
- A note about anything intentional that might otherwise look like a mistake.
Leaving headroom matters more than most people expect — what is headroom covers why.
Where to go next
- How to master a track for the step-by-step.
- How to build a mastering chain for the processing order.
- What to listen for when mastering for the checks.
- How the pros master for what actually differs at a professional level.
The tools that matter most at this stage are the ones that measure rather than change: SPC SpectraScope for spectrum, loudness and true peak, and SPC Limit Breaker for the final ceiling.
Frequently asked questions
What is a master in music?
The final version of a track, prepared for release. It is a single stereo file at the delivery format and level, made from the finished mix and checked so it plays correctly everywhere.
What does mastering actually do?
It makes small tonal and dynamic adjustments to the finished stereo mix, sets the final level and ceiling, checks technical safety such as true peak and mono compatibility, and makes the track consistent with the rest of the release.
Can mastering fix a bad mix?
Only slightly. Mastering works on the whole stereo file, so it cannot separate elements. If the vocal is buried or the kick and bass collide, that is a mix problem and it has to be fixed in the mix.
Do I need to master my own music?
If you are releasing it, it needs a master of some kind. Doing it yourself is entirely possible for most modern releases, especially if you keep the changes small and check the technical requirements carefully.
Should mastering be done by someone else?
A second set of ears helps because they hear the track without knowing what it was supposed to be. That is a real advantage, not a formality. But a careful self-master with good references beats a rushed outside one.