digislicer

A new SRC machine for the Digitakt (mk1), DIGISLICER: the SLICE machine with a slice editor, for OS 1.53 and 1.54, as an elekloader mod.

What's new in 2.5: STRETCH

Knob G of DIGISLICER's SRC page is now STRETCH (STR). It changes a slice's length without changing its pitch, and it takes GRID's place.

• The values: OFF, or a speed from x0.25 (four times as long) through x1.00 to x3.29.
  • 0-7 is OFF. From 8 up it goes an octave every 32: x0.25 at 8, x0.50 at 40, x1.00 at 72, x2.00 at 104.
• Pitch: the slice keeps its pitch from TUNE, its LFO and the note. At x1.00, TUNE changes the pitch without changing the length.
• Locks and LFOs: STRETCH locks per step, and the LFOs reach it, as any SRC parameter.
• Hits stay in time: in a window of several slices (LEN), each slice starts when its time comes, so hits inside a stretched window are not doubled or smeared.
• Up to 4 tracks stretch at once. A note that would make a fifth plays unstretched. Stretched playback runs on the Digitakt's main CPU, and 4 tracks at x0.25 are about as much as it has to spare.
• Forward PLAY only: FWD.L plays once when stretched, and REV, REV.L and PIPO play unstretched.

GRID is gone from DIGISLICER. A sample plays its own slices (from the editor), or AUTO's (on its transients) when it has none. AUTO's are found the first time a track plays the sample, and an even 16 grid plays until they're ready. For equal slices, use the editor's CREATE GRID: it makes them the sample's own.

Kits from older versions load with STRETCH OFF, because GRID's old values (0-5, AUTO being 5) all read as OFF. Your slices on the +Drive (/cfw/slices.a, .b) are unchanged.

The idea of peak-aligned splices and of starting hits on time comes from Heavylight Industries' capicola ("Keyframe Time Stretching via Extrema Sampling", DAFx26). The code is digislicer's own, in integers (the Digitakt has no FPU), and GPL-2.0-or-later.

The README has every control.

Files

• The files without -os1.54 are for OS 1.53. Pick the files for the OS your unit runs; elekloader refuses the others.
• digislicer 2.5 needs core 3.0 or later and elekloader's machine-pages mod, as 2.3 and 2.4 did. Core 4.0 and machine-pages 1.2 are attached, the same files as on core-v4.0 and machine-pages-v1.2. For core 2.1, use digislicer 2.2.

Install

1. Get the stock OS file your unit runs, Digitakt_OS1.54.syx or Digitakt_OS1.53.syx, from Elektron.

2. Build with elekloader, from source or in its web shop:

   python -m elekloader.patch --stock Digitakt_OS1.54.syx \
       --mod core-4.0-os1.54.elemod --mod machine-pages-1.2-os1.54.elemod \
       --mod digislicer-2.5-os1.54.elemod \
       --out Digitakt_OS1.54-slicer.syx --version DS25
   

3. Send the .syx to the unit as you would any OS update.

Recovery: hold FUNC while powering on for the startup menu, then send the stock OS file. elekloader never changes the bootloader.

It combines with digihealth and with the other machines built on core 3.0, such as NEIGHBOR 0.7.

Checked

• On a unit: a build of exactly these files (with digihealth 1.0) was tried on a Digitakt.
• In digikit's emulator, on OS 1.53 and 1.54, with core 4.0 and machine-pages 1.2:
  • At x1.00 the stretched sound matches the stock voice's (correlation 0.999, same level).
  • A 178 ms slice sounds 352 ms at x0.51 and 720 ms at x0.25.
  • Knob G reads OFF and x0.25-x3.29. CREATE LINEAR and RANDOM LOCKS still work with it set.
  • With 6 tracks triggered at once, 4 stretch.
• CPU, in the emulator's cycle model of the audio render: with 8 tracks triggered and 4 of them stretched at x0.25, the render takes 73% of each block on average and 87.8% at worst, against 63.7% stock.
• These files are byte-identical to the builds tested.

Custom firmware is at your own risk. Not affiliated with Elektron.