Free AI mastering: hear the whole master before you pay a cent.
Most “free” mastering is a 30-second preview or a watermarked file. ZERRRO Engine gives you the full master, full length, with an A/B against your own mix, for free. If you want to keep it, the download is 2.99 EUR.
Full length, no watermark, with measured LUFS and true peak and a loudness-matched A/B.
Change the genre, character, EQ or loudness and render again as often as you like.
24-bit WAV and 320 kbps MP3 of the master you heard. No subscription needed.
What is free, and what is not
We would rather say it upfront than after you uploaded: listening is free, downloading costs 2.99 EUR per track or less with a plan.
Free: the full preview
Your master, end to end, playing in your browser. Not a snippet, not a demo loop.
Free: shaping and re-renders
Pick a genre, drag EQ dots, type a wish in plain words and render again. None of it costs a credit.
Paid: the files
The 24-bit WAV and MP3 cost one credit. Plans start at 4.90 EUR a month with the first month free.
Hear it. Shape it. Then decide.
Upload & check
Bit depth, sample rate, true peak, clipping and loudness of your premaster are measured in seconds. If the file is already limited or clipping, you find out before anything is processed.
Pick your genre
Reference profiles for techno, house, trance, drum and bass, dubstep, afro house, EDM and more, built from released music and adapted to your mix. Or upload your own reference track.
Shape it while it plays
Pick a character, drag the EQ dots, or type what you want in plain words. Every change is audible immediately, and none of it costs anything.
A/B and decide
Compare the master with your mix at matched loudness, read the measured LUFS and true peak, and render again for free if it is not there yet. You pay only when you download.
Preview free. Pay only for the download.
When you unlock a master
- The master you heard, full length, as 24-bit WAV and 320 kbps MP3
- Your loudness target, true peak never above 0 dBTP (−1 dBTP for streaming)
- Download link right away and by email
- Files kept in My Masters for 12 months
Before you upload
- WAV or AIFF, 24-bit, at your project’s sample rate
- 3 to 6 dB of headroom
- No limiter on the master bus
- Full length, no fades you would not release
Questions producers ask
Is there completely free AI mastering?
Listening to the full master, comparing it and rendering again are free here. Downloading the WAV and MP3 costs 2.99 EUR per track. Services that give away the files for free usually limit quality, length or add a watermark.
Do I need an account to try it?
No. The preview needs no account and no card. You only sign in or check out when you download.
Is there a watermark on the preview?
No. The preview is the actual master, full length.
What does it cost if I release a lot?
Plans start at 4.90 EUR a month for three masters, with the first month free. Studio is 9.90 EUR for ten.
Hear your track mastered first. Decide after.
Drop a premaster or take one of the demo tracks for a spin. Free, right now, in your browser.
Master a track free → No signup to preview · no card · no install