Mixing vs Mastering: What's the Difference and Do You Need Both?

"Do I need mixing or mastering?" is one of the most common questions I get, and it usually comes from someone who's been told they need both but isn't sure why. The two words get thrown around together so often that they start to sound like one job. They aren't. They're two different stages, done for two different reasons, and knowing the difference will save you time, money and a lot of frustration.

Here's how I explain it in plain terms.

What mixing is

Mixing is where the song gets put together. You hand over the individual tracks, the kick, the snare, the bass, the guitars, the keys, the lead vocal, the harmonies, and the mix engineer turns all of those separate pieces into one stereo song.

That means making a lot of decisions, track by track:

• Balance. How loud each part is against everything else, and how that changes from the verse to the chorus.

• Tone. EQ to give every instrument its own space, so the bass and kick aren't fighting and the vocal isn't buried under the guitars.

• Dynamics. Compression and automation so the vocal sits steady and the drums hit the way the song needs.

• Space and depth. Panning, reverb and delay to put things left, right, close or far away.

• Feel. The small moves that make a chorus lift or a bridge drop, so the song tells its story.

The key point is that a mix engineer can reach inside the song. If the snare is too loud in the second verse, I can turn down just the snare in just the second verse. If the vocal gets lost on one word, I can fix that word. Every element is still separate and adjustable.

What mastering is

Mastering happens after the mix is finished. Instead of dozens of tracks, the mastering engineer works on the final stereo file, the whole song at once.

The job is to take a mix that already works and get it ready for the world:

• Subtle overall EQ so the song translates on earbuds, car speakers and big systems.

• Gentle compression and limiting to bring the level up where it should be without crushing the life out of it.

• Making sure peaks are under control so the file holds up when streaming services encode it.

• On an EP or album, making the songs feel like they belong together, with consistent level and tone from track to track, plus spacing and sequencing.

• Delivering the right files and formats for release.

What mastering can't do is reach inside the song. If the vocal is too quiet against the guitars, a mastering engineer can't turn up only the vocal. Any move made in mastering touches everything at once. I went deeper on this in What Does Mastering Actually Do? (And What It Can't Fix).

An easy way to remember it

Mixing decides how the parts of the song relate to each other. Mastering decides how the finished song relates to every other song your listener will hear before and after it.

If your problem is inside the song, a buried vocal, a boomy bass, a chorus that doesn't hit, it's a mixing problem. If your problem is about the finished file, it's too quiet next to other releases, it sounds thin in the car, the songs on your EP jump around in volume, that's mastering territory.

Do you really need both?

For a release you care about, yes, in almost every case. They solve different problems, and skipping one usually shows.

Skip mixing, and mastering gets asked to fix things it can't fix. A master can only polish what's already there. Pushing a rough mix through a limiter just makes the problems louder.

Skip mastering, and a great mix can still come out sounding quiet, uneven or inconsistent next to everything else on a playlist. Loudness matters less than people think now that streaming services adjust playback levels, which I explain in How Loud Should My Master Be for Spotify?, but translation, peak control and consistency across a project still matter a lot.

There are a few cases where you might only need one:

• Your song is already mixed and you're happy with it. You just need mastering.

• You're sending a mix to a label or a separate mastering engineer. You just need mixing, delivered with headroom so the next engineer has room to work.

• It's a rough demo for the band or a pitch. A quick mix may be plenty for now.

Should the same engineer do both?

It can go either way. A separate mastering engineer brings a fresh set of ears to a mix they've never heard, and that outside perspective can catch things. Having one engineer handle both means the person mastering already knows exactly what the mix was going for, and the whole process stays in one place.

What matters most is that whoever does each stage knows which job they're doing. When I mix, I'm thinking about the song. When I master, I'm thinking about the finished record.

How to set yourself up for both

The better the files you send, the better both stages go. A few habits help:

• Prep your tracks properly before mixing. My stem prep checklist covers naming, start points and what to leave off.

• Don't put a limiter on your mix bus before sending it for mastering unless your mastering engineer asks for it.

• Leave some headroom on the final mix so the master isn't starting already pinned.

• Send a reference track or two so everyone is aiming at the same sound.

The bottom line

Mixing builds the song. Mastering finishes the record. They're different jobs with different tools, and for a release you want to stand behind, you'll almost always want both done with care.

If you've got tracks ready to go, take a look at my online mixing and mastering page and send me a note about your song. I'm happy to listen and tell you what it needs.

— Jim

If you'd like one-on-one help with your own mix, vocals or audiobook, you can book an online session with me.