Loop Sync for Elektron Analog Rytm

Keeps sample loops in time with the project tempo by repitching them; AUTO reads each loop's tempo from its length, locks and scenes included.

Module version 0.2.0-experimental. Base firmware: 1.74.

About this module

In AUTO the mod works out each loop's source tempo from the length of the sample that plays (between STA and END, 4/4, cut on the bar) and adds the matching pitch shift to the track's effective TUN every audio block, after parameter locks, scenes and the LFO. A SMP lock or a scene that changes the sample is followed, each sample by its own length. A percentage correction (FUNC + FIN) on top of any mode puts loops with a tail or a gap back in time. Pitch follows tempo; no time-stretch.

• AUTO: no tempo to enter for loops cut on the bar.
• SMP locks and scenes stay in time, each sample from its own length.
• TUN stays yours: the shift is added on top, so a TUN lock still transposes.
• Trailing silence is left out automatically, and each sample keeps its own correction.

How to use it

1. Load a loop cut on the bar, for example one bar at 120 BPM, on a sound track with a trig on step 1.
2. Press SMPL, hold FUNC and turn TUN to AUTO: the box reads AUTO over 1BAR 120.0, and SYNC appears at the bottom right.
3. Play and change the tempo: the loop follows, and the pitch glides with each tempo step. Lock SMP on a step to another loop: it is in time too, from its own length.
4. For a loop with a tail or a gap, hold FUNC and turn FIN until it sits in time; that sample keeps its correction. Save the project to keep it.

Controls

MODE

OFF, AUTO, 1 BAR, 2 BAR, 4 BAR or 8 BAR. FUNC + TUN on the SAMPLE page. Kept in the sound.

ADJUST

Correction of the source tempo of the sample the selected track plays, -12.7 to +12.7 % in 0.1 % steps, sample slots 1-123. FUNC + FIN on the SAMPLE page. Kept per sample slot with the project.

Compatibility notes

• Pitch follows tempo: no time-stretch.
• The shift is clamped to TUN's +-24 semitones and skipped beyond a factor of 8.
• The silence check sees only digital silence under 5 % of a sample; other mis-cut loops need the per-sample correction.
• The loop length comes from the sound's own STA and END: locks and LFOs on STA or END play another region at the same speed.
• The SYNC mark shows only on the SAMPLE page.
• Hooks the audio interrupt one instruction after rytm2_mods lfo-rnd's site; the pair is not tested.

Test evidence

Emulator (rytm-emu, OS 1.74, build LS18): loops of 120 and 100 BPM alternating by SMP lock, a padded loop, a mis-cut loop with its correction and a STA-locked slice all in time at 127 BPM. Earlier builds tested by the author on a unit; LS18 awaits the unit test. See TESTING.md.