What Is Mastering? What It Does and When You Need It

The short answer

Mastering takes a finished stereo mix and prepares it for release. It sets the final loudness and tonal balance, makes sure the track translates on every kind of speaker, and delivers the files in the formats your distributor, label or pressing plant needs.

What mastering does

• Translation. Your mix was made on one set of speakers in one room. Mastering checks and adjusts it so it holds up on club systems, earbuds, car stereos and phone speakers.
• Tonal balance. Small EQ moves that fix what your room may have hidden: a little too much low mid, a top end that's slightly harsh.
• Loudness and dynamics. Setting the level so the track is competitive without crushing the life out of it. More on that in how loud your master should be.
• Consistency. On an EP or album, every track needs to sit together in level and tone.
• Delivery. Final WAV files, a DDP image for CD manufacturing if needed, and a version prepared for vinyl if you're pressing records.

What mastering can't do

Mastering works on the whole track at once. It can't turn the vocal up without turning the snare up too, and it can't fix a kick and bass that clash. Those are mix problems. If the mix isn't right, the honest answer is to fix the mix first, or use stem mastering if the issue is small.

Is your track ready for mastering?

A good test: if you'd be happy releasing the mix at a lower volume, it's ready. If you still want to change balances, it isn't. Before sending, run through this preparation checklist.

Why use an engineer instead of an automated service

Automated mastering applies a chain of processing based on genre presets. An engineer listens to your track, hears what it needs, and talks to you about it. For a demo, automation might be fine. For a release that represents you, a second set of trained ears is the point.