Stemquill: Turn audio stems into MIDI for any DAW

Hi Product Hunt! 👋 I'm Bill, the one-person team behind Skynr Labs.

I record at home, and I kept running into the same wall: stem separators are everywhere now, but a stem is still just audio. You can't swap the drum kit, fix one wrong note or change the groove. I wanted to get from "I have the stem" to "I have the part" so I could rebuild it with my own sounds.

So I built Stemquill. Drop in your stems and it:

🥁 Writes drums on the right notes for your plugin: kick, snare, hi-hats, toms, crash and ride, with maps for EZdrummer, Addictive Drums, Superior Drummer, MT Power Drumkit, FL Studio FPC and Ableton Drum Rack

🎸 Turns bass and vocals into melody lines, and guitar, keys and synths into chords

⏱️ Measures the real tempo, so the MIDI lines up with your DAW's grid

🎼 Finds the song's key and can pull stray notes into it

▶️ Lets you hear the MIDI with built-in sounds, mixed with the original stem, before you save

It's made with AI-generated stems in mind too: Suno's stem names are recognized automatically, and slightly off-pitch AI vocals still come out as the notes that were sung.

Everything runs on your own computer, on Windows and Mac. No account, no uploads, no subscription. It's $4.99, and the source code is public on GitHub.

I'd love to hear what you think, and which stems give it the most trouble. That's what I'll work on next. Thanks for checking it out! 🙏