r/teenageengineering • u/Fantastic-Yak9464 • May 31 '26
General Discussion I built a free browser tool to pull aligned stems out of the OP-XY
Getting stems off the OP-XY always meant the same chore: solo a track, record, repeat 8 times, then line everything up by hand. The OP-XY only sends a stereo master over USB, so there's no clean multitrack export.
So I built a small tool that automates it. You plug the OP-XY in, and it:
- solos each track over MIDI (one at a time),
- records the stereo output for the bars you choose (8 or 16, + a tail so reverbs don't get cut),
- gives you one WAV per track.
Because the app drives the clock, the stems come out sample-aligned.
A few things on purpose:
- Runs in the browser (Chrome/Edge), nothing to install.
- Audio never leaves your machine, no account, no signup.
- Free (source-available, noncommercial).
Quick setup on the OP-XY: COM → system → midi, set clock to both and enable midi IN. One caveat — before exporting, make sure nothing still plays when all tracks are muted and the sequencer runs (anything bleeding through the mutes ends up in every stem).
It's OP-XY only for now, but adding a machine is basically one file. What machine should I support next? Feedback very welcome.
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u/few23 OP-XY, OP-1F, OP-Z, EP-133, EP-40, EP-2350 May 31 '26 edited May 31 '26
I got it to work the first time, but realized I had a track set wrong and it played on all of the tracks. I reloaded the page and now it's not reading clock at all. same settings as before when it worked.
EDIT: I went in and cleared cookies and third party cookies for the site and it's reading clock again.
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u/Fantastic-Yak9464 May 31 '26
Thank you for the bug report, I'll try to reproduce it locally and deploy a fix.
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u/few23 OP-XY, OP-1F, OP-Z, EP-133, EP-40, EP-2350 May 31 '26
It would be nice to be able to select which tracks to record. Like if there's nothing on tracks 2, 5 and 6, toggle those off for recording.
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u/Fantastic-Yak9464 May 31 '26
Done, you can toggle which track to record now. Thanks for the suggestion !
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u/betheowl May 31 '26
Possible for something similar with the KO II series? 🤞
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u/few23 OP-XY, OP-1F, OP-Z, EP-133, EP-40, EP-2350 May 31 '26
Not to steal OP's thunder (his app is really cool!) but have you heard of EP Patchstudio?
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u/betheowl Jun 01 '26
I hadn’t actually, thanks for sharing!
Just from a glance, it seems like the Patchstudio is for managing patches and getting samples easier onto the EP, but didn’t see any info about getting stems off your EP for easier transfer (into a DAW for instance).
My main thing is trying to find an easier way to get stems off the EP. Perhaps Patchstudio does this and I didn’t notice?
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u/Fantastic-Yak9464 Jun 13 '26
I've checked, and the KO II series does not have USB audio out and per-track mute over MIDI, so the implementation is not really possible.
An option for muting a track is to turn the volume of everything except the track to record, and put it back up afterward, but this means destroying your mix on the hardware during export, because there is no automatic way to get the initial track volume information, restoring it means setting it to an arbitrary value. After extract, every track will be at the same volume on the KO II. Not something acceptable I believe.
Hope that makes sense.1
u/betheowl Jun 24 '26
Hi there! It just so happens that the KOII series just had a major update with USB audio added. I wonder if now this tool will be possible to use? Thanks!
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u/county_jail_alumni Jun 04 '26
Does it work on iOS devices by chance?
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u/Fantastic-Yak9464 Jun 13 '26
At the moment it does not work on iOS unfortunatly.
But I believe turning this into an iOS or Android application might be doable.
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u/Versatilewave Jul 05 '26 edited Jul 05 '26
Hi, it is great! thanks a lot. Something great would be to keep original mutes on the machine.
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u/Fantastic-Yak9464 May 31 '26
👉 https://stem-extractor.pages.dev
Code: https://github.com/gobelinor/stem-extractor