Record and loop MIDI notes (on/off timings with velocity) with the Perpetual MIDI Looper. This approach to looping (vs audio) preserves flexibility in the signal chain, allowing you to repurpose, modulate, edit, and reconfigure what exactly the notes are doing.
There are onboard controls for non-destructive quantization (you can experiment with varying degrees of quantization and turn it right back off if you like), transposition, rate adjustment (half speed to double speed) without affecting pitch, and velocity adjustment.
Loops can be synced via a trigger pulse that kicks it back to the beginning, with a sync out for sending the same such pulse to other devices, perhaps more MIDI loops. Loop lengths can be trimmed with dials or auto-trimmed (neighboring orange buttons) to extract start or end silence. Recording can likewise be controlled via trigger or gate signals and likewise sends such signals of its status so that recorded loops can be the exact length of another sequence, with single sample precision.
It’s a great way to get a modular setup humming with all sorts of harmonies, and the controls give you the opportunity to for interesting variations where a copied device might be transposed down an octave and sped up to double speed for a fugue-like harmony on another oscillator, for instance.
Since the loop data is saved within the device’s preset settings, it can easily be pushed into other patches, sent to friends, or copied into indefinite numbers of duplicates with ease.
If you like looping but don’t like the commitment, try the Perpetual MIDI Looper.