Professional audio mastering in your browser. No installs, no subscriptions.
Drop audio file here or
MP3, WAV, FLAC, AAC, M4AOBRA Audio Mastering is a free, browser-based mastering tool built for musicians, producers, and audio engineers. No downloads, no plugins, no subscription required. Drop your track, shape your sound, and export a release-ready WAV — all from your browser.
The mastering chain includes a professional-grade 5-band parametric EQ (80Hz, 250Hz, 1kHz, 4kHz, 12kHz), glue compression for mix cohesion, a true peak limiter with adjustable ceiling, M/S stereo width processing, and LUFS-targeted loudness normalization — the same tools used in professional mastering studios.
Quick-fix controls like de-harsh, clean low end, add air, and tape warmth let you polish your master in seconds. EQ presets for vocals, bass-heavy tracks, bright mixes, and warm masters give you a starting point, while the faders give you full manual control.
Export in WAV format at 44.1kHz or 48kHz, 16-bit or 24-bit — ready for Spotify, Apple Music, DistroKid, TuneCore, CD Baby, or any distributor. Your audio is processed entirely in your browser using the Web Audio API. Nothing is uploaded to any server.
OBRA Audio Mastering is currently in open beta. Using the mastering tool — including export — is completely free, with no account or sign-in required.
What is audio mastering, and why does my track need it?
Mastering is the final polish pass on a mix — EQ balance, glue compression, stereo width control, and loudness normalization — that gets a track ready for release. It's what makes a home recording sit next to a professionally released song on Spotify or Apple Music.
Is it really free?
Yes. OBRA Audio Mastering is 100% free to use — no account, no subscription, no credit card. Master and export your WAV file directly from your browser.
Is my audio uploaded to a server, or processed locally?
Processed 100% locally in your browser. OBRA Audio Mastering runs on the Web Audio API — decoding, EQ, compression, limiting, and export all happen on your device. Your audio file is never uploaded or sent to any server.
What formats can I import, and what do I get back?
Import MP3, WAV, FLAC, AAC, or M4A — the browser decodes your file natively, no conversion needed. Export is lossless WAV at 44.1kHz or 48kHz, 16-bit or 24-bit, ready for Spotify, Apple Music, DistroKid, or any distributor.
What LUFS loudness target should I use?
Around -14 LUFS integrated is the common streaming target, which is why it's the tool's default. The Target slider lets you dial in anywhere from -16 to -6 LUFS depending on where the track is headed.
Can I use the mastered track commercially?
Yes. You own whatever audio you upload and export — OBRA Audio Mastering doesn't claim any rights over your files or add watermarks. Release it, sell it, sync it, or distribute it anywhere you like.