Multi-Instance MIDI Mapping & Stop Button Refinement

Update: January 27, 2026  v1.09s

Multi-Instance MIDI Mapping & Stop Button Refinement

Hey everyone,

I've been working on some dual-looper setups lately—building a verse arrangement on one instance and a chorus on another—and discovered something worth sharing.

Independent MIDI Mapping Per Instance

Each UndoLooper instance stores its own MIDI mappings completely independently. You can load up two instances (or ten, if you're feeling ambitious), map each one to different MIDI notes or CCs, and they'll coexist perfectly. This opens up some interesting workflow possibilities, like mapping one looper's STOP button to the same footswitch as another looper's PLAY button for seamless section transitions.

Stop Button Timing Fix

During testing, I noticed the STOP button wasn't behaving quite right for multi-looper workflows. For single-looper use with quick taps, it was barely noticeable, but in a dual-looper setup the timing issue became evident.

What changed:

The STOP button previously triggered on release rather than press. It would start a timer when you pressed down, then execute the action when you let go—checking whether you'd held it long enough (2+ seconds) to trigger a CLEAR instead of just a STOP.

This introduced 50-300ms of latency depending on how quickly you released the footswitch. Not ideal when you're trying to nail tight transitions between loopers.

The fix:

STOP now triggers immediately on press, while the 2-second hold-to-clear functionality still works perfectly—it just checks the duration on release. No changes to the audio engine; just smarter MIDI handling that keeps everything lean and responsive.

Why it matters:

For dual-looper setups with overlapping mappings (e.g., Looper A's STOP mapped to the same footswitch as Looper B's PLAY), this eliminates timing slop entirely. Press once, both loopers respond instantly. The transitions are now frame-accurate.

If you've been experimenting with creative MIDI mappings or multi-instance setups, I'd genuinely love to hear about them. UndoLooper is built for musicians who care about this level of control, and I'm always learning from how you're using it in the real world.

And the standalone for Windows has an ICON now.

–Ryan