Zoom MS pedals (MS-50G, MS-60B, MS-70CDR) ignore MIDI clock, so a tempo-synced LFO or pattern slowly drifts away from your drum machine. This script fixes that for the custom effects in the Matujuice Zoom MS pack (v1.3 or later): DualShft, Choral, EuGate, DubSiren and Scrub.

How it works: in these effects every Tempo knob holds each BPM twice (40..240, then the same BPMs again). Jumping from a BPM to its twin restarts the effect without changing the tempo. On each downbeat the script flips the Tempo knob of the effects in slots 1 to 3 to its other copy, a few ms early so the edit lands on the beat. It also follows AUM’s tempo.

Needs:

The effects pack: https://github.com/matujuice/zoom-ms-zdl-effects-pack/releases (v1.3 or later). It does nothing with stock Zoom effects.
AUM as the master clock, with the drum machine following AUM’s MIDI clock.
The pedal on USB (camera adapter plus powered hub). AUM routing: Mozaic MIDI out to the Zoom.

Controls:

Early: ms before the downbeat the edit is sent (default 17; 12 measured on an MS-60B, plus 5).
Every: restart every 1, 2, 4 or 8 bars.
BPM: tempo sent when Follow host is off.
Follow host: right half follows AUM’s tempo, left half uses the BPM knob.
Pads 1..3: tap to pick the effect in slot 1..3. Only the first three effects of a patch accept edits from outside.
Pad 4: sync on/off.

Tested on an MS-60B running MS-50G firmware 3.10, iPhone with AUM and Mozaic, Digitakt following AUM over USB. Other pedals are untested; reports welcome.

Full guide: https://github.com/matujuice/zoom-ms-zdl-effects-pack/blob/main/docs/IPHONE-SYNC.md