Reference mastering online
What are we mastering today?
Free, 2 songs a day · No sign-up · Nothing leaves your device
WAV · AIFF · FLAC · MP3 · M4A · MP4 · MOV · up to 20 min
For producers and engineers
Got 5+ songs on Spotify you produced, mixed or mastered? You’ll love OBRA.
Your credits and verified streams on one link, updated every day. The profile that gets you your next client.
Free. No credit card.
SkaaryProducer · Mixing Engineer3,453,245,941Verified streamsWorked with Bad Bunny · Ozuna · Anuel AA01
GARABATTOProducer · Mixer9,382,868,953Verified streamsWorked with Quevedo · Saiko · Feid02
Adrian BreakspearProducer · Mixer2,540,930,163Verified streamsWorked with The Kid LAROI · Gang of Youths · BABYMETAL03
FECTRO178,744,097Verified streamsWorked with Abraham Mateo · YSY A · María Becerra04How it works
- 01
Drop your mix
Your song as a WAV, FLAC, MP3 or video. It stays on your device.
- 02
Drop a song you love
The reference. We read its tone, punch, width and loudness, and never keep it.
- 03
Listen, then download
Your master next to the reference at the same loudness. Choose how close it goes, then download it with the song price or OBRA PRO.
What the master does
- ListensThe whole song
Measures your mix the way an engineer would: tone in sixth-octave bands, dynamics band by band, stereo, phase and true peaks.
- ToneUp to 8 bands
Compares its tone with how professional masters of its style sound and evens it out with precise EQ moves, cuts first.
- Multiband4 bands
Gentle multiband compression keeps the lows, mids and highs steady from the first verse to the last chorus.
- Glue and punchBus comp · transients
A bus compressor glues the mix, a transient shaper brings the hits forward and tape or console saturation adds warmth.
- StereoMono bass
Opens the image above 140 Hz and keeps the bass in mono, so it still hits on phones and club systems.
- LoudnessTrue peak 16x
A clipper and a true-peak limiter reach the level, measured in integrated LUFS (ITU-R BS.1770-4) on the file you download.
Three masters, side by side
- Natural
Breathes. Close to the level streaming plays at, with your dynamics intact.
- OBRA
Our balance: fuller tone, wider stereo and more punch.
- Loud
Dense and upfront, for clubs, DJ sets and loud genres.
Switch between them while it plays, and against your original at the same loudness: louder always sounds better, so we take that out of the comparison.
Loudness targets by platform
| Platform | Loudness | Peak ceiling |
|---|---|---|
| Spotify | −14 LUFS | −1 dBTP |
| YouTube | −14 LUFS | −1 dBTP |
| Tidal | −14 LUFS | −1 dBTP |
| Deezer | −15 LUFS | −1 dBTP |
| Apple Music | −16 LUFS | −1 dBTP |
| Club / DJ | −9 LUFS | −0.3 dBTP |
Streaming services turn louder masters down to their reference level. The Platforms view shows how each one will play your master.
Free, and more when you need it
- Free
- 2 songs a day
- All three masters, the Studio and every meter
- WAV or FLAC up to 24-bit / 48 kHz
- No account
- One song$3 / €3 / £3
- Unlimited downloads of that song for 30 days
- 88.2 / 96 kHz and 32-bit float
- Reference master included
- No account, no subscription
- OBRA PRO
- Unlimited mastering and every tool
- Vocal + beat mixes and albums
- Your artist profile on OBRA
Listening is always free and complete. Vocal + beat ($5 / €5 / £5) and Album ($9 / €9 / £9) download per job, or come with OBRA PRO.
Frequently asked questions
Is OBRA online mastering really free?
Yes. Two songs a day are free, with no account, no card and no watermark: all three masters, the Studio and every meter included. Each extra song is a one-off $3 / €3 / £3, or unlimited with OBRA PRO. Listening is always free.
Do I need to sign up or install anything?
No. Drop your mix into the page, listen and download. It works in any modern browser, on desktop and mobile.
Is my song uploaded to a server?
No. The whole mastering engine runs in your browser, so your file never leaves your device and nothing is stored on our side.
What loudness should I master to for Spotify and Apple Music?
Spotify, YouTube and Tidal play music at about −14 LUFS and turn louder masters down; Apple Music plays at about −16 LUFS. Natural stays close to that and keeps your dynamics; OBRA and Loud are denser for the genres that want it. The Platforms view shows how each service will play your master, and the Volume knob sets the level to taste.
How accurate are the LUFS and true-peak numbers?
Loudness is integrated LUFS following ITU-R BS.1770-4 (K-weighting and gating), with short-term, momentary and loudness range too. True peak is read with oversampling and the limiter works on those peaks. We measure the exported file itself, so the report is what you download.
Which files can I master, and what do I get back?
WAV, AIFF, FLAC, MP3, M4A and the sound of MP4 or MOV videos, mono or stereo, up to 20 minutes. You download a 24-bit or 16-bit WAV, or a FLAC, at 44.1 or 48 kHz, ready for DistroKid, TuneCore, CD Baby or any distributor. 88.2 / 96 kHz and 32-bit float come with a paid song or OBRA PRO.
Is this AI mastering?
It is automatic mastering that works like an engineer: it measures your mix, compares it with how professional masters of its style sound and decides the EQ, compression, stereo and limiting for your song. Every move is written down with its number and its reason, and you can change any of them in the Studio.
Can I master with a reference track?
Yes. Drop a song you love next to yours and the master moves towards its tone, punch, width and loudness, compared at the same level. Listening is free; a reference master downloads with the song price or OBRA PRO.
Can I mix my vocal over a beat?
Yes. Drop your beat and your vocal, even one recorded on a phone: we line them up, clean the vocal, level it, give it space and master the mix. Listening is free; the download is $5 / €5 / £5 or included with OBRA PRO.
Can I release the mastered track commercially?
Yes. You keep every right you hold in your music. OBRA claims nothing and adds nothing to the file.