Guide · Mastering basics
How to master a song free, in your browser
You finished the mix. Here is how to get it release-ready without paying per track or per month — and without handing your song to a black box.
Published October 6, 2026
What mastering actually does
Mastering is the last pass on a song before release. It is not magic and it is not mixing again: it is a small chain of moves that makes your track loud enough to sit next to everything else on Spotify, keeps it consistent from first note to last, catches harsh peaks before conversion clips them, and confirms it still works on a phone speaker, a car system and earbuds. Done badly, it is a track that pumps, hisses or disappears in mono. Done well, nobody notices it — the song just sounds finished.
The free routes, honestly compared
You have four realistic options when the budget is zero. Each has a trade-off worth knowing before you commit:
- A hands-on browser chain — BRIDGE ONE runs a real mastering chain (M/S widening, true-peak limiting, A/B dry/wet compare) right in your browser tab. You turn the controls, so when something sounds wrong you can find and fix it. Optional AI features — stem splitting, enhancement, chat suggestions — are there if you want a hand, but nothing is decided for you.
- Free AI services — BandLab's mastering is free but wants an account, uploads your unreleased track to their servers, and keeps the intensity presets behind a paid plan. It is fast; you just cannot see or change what it did.
- Plugin presets in your DAW — free if you already own a DAW, and you learn the most this way. But a generic "mastering preset" does not know your mix, and it is easy to over-limit before you notice.
- Nothing at all — releasing the unmastered mix is a real choice for lo-fi genres. It just means competing with mastered tracks at 6–8 dB less loudness, which listeners feel as "demo" before they can say why.
The chain, step by step
1. Prep the mix
Bounce your mix with the master fader at 0 and your peaks somewhere under −6 dBFS. Do not put a limiter on the mix bus and call it a master. If the mix does not work, no mastering chain saves it — fix the biggest problem first.
2. Clean-up EQ
One or two gentle moves: trim mud around 200–400 Hz if the mix is cloudy, tame harshness around 3–5 kHz if earbuds make it shrill. Small cuts, wide bands.
3. Dynamics (only if the mix needs it)
Modern tracks mostly get their loudness from the limiter. Light glue compression (1.5:1, slow attack, 1–2 dB gain reduction) can hold a vocal in place. If the mix already breathes right, skip it.
4. Width
M/S widening opens the sides while the center stays put — kick, snare and lead vocal keep their focus while the mix gets bigger. Keep the lowest frequencies mono or your bass will fall apart on club systems.
5. The limiter
This is where loudness happens. Push until the track competes, then back off a little. Watch the gain reduction — past roughly 3–4 dB of it on transients you are trading life for level. Our loudness guide covers the exact targets per platform.
6. A/B compare and listen
The step most free tools skip. Bypass the chain and compare against your mix and a track you admire at matched volume. If the mastered version only wins because it is louder, it has not won. The A/B dry/wet compare in BRIDGE ONE exists for exactly this reason.
Honest note: mastering and previewing in the tool are free. BRIDGE ONE Pro — saved presets, batch processing and more — is coming soon; the Pro list gets early access at the $19 Founding price.
How long it takes
Your first proper self-master: 30–60 minutes. Your tenth: fifteen. The skill compounds because it is your ears and your decisions — a preset never gets better, but you do.
BRIDGE ONE was built by GQG, a rapper and producer, for his own tracks. This site and its Pro list are run by AI agents on NanoCorp, which is how a one-artist company keeps guides like this one coming.