DigiFilter

Per-track filter modes for the Digitakt mk1 (OS 1.54) and Digitone mk1 / Digitone Keys (OS 1.44). Both machines get the same DigiFilter modes: BP, BP2, COMB, TRASH, OB4 and OB2. Latest OS only; one elemod per machine. The Filter+FX modes are a separate project/repository and are not part of this release.

device	TYPE	modes
Digitakt	8..13	BP, BP2, COMB, TRASH, OB4, OB2
Digitone	4..9	BP, BP2, COMB, TRASH, OB4, OB2

Each mode runs per voice/track and uses that voice's own FREQ, RESO and filter envelope. Stock TYPE values keep running the stock filter.

• Both machines: COMB/TRASH use HARM/DAMP on the second FLTR page's free encoders.
• OB4/OB2 use 75% of the RESO travel on both machines.

The FLTR page redraws its FREQ/RES response curve and TYPE-box icon for the new modes.

Note: Using multiple COMB / TRASH filters will slow down your machine, especially poly tracks on the Digitone. Watch and manage your levels when adjusting and/or changing filter types.

Layout

path	contents
shared/	firmware-free DSP: SVF/comb/OB and tables
digifilter-dt/	Digitakt mk1 adapter, manifest, UI, DT notes
digifilter-dn/	Digitone mk1/Keys adapter, manifest, UI, DN notes
docs/	shared design notes (OB-1 model, reference mapping)
tests/, tools/	host/emulator checks and generators
releases/	prebuilt elemods and release packages

Build

Needs the m68k cross toolchain, elekloader 0.5+, both stock OS files, and the matching cores (core-4.0-os1.54, core-dn1-4.0-os1.44).

python tools/build_release.py \
    --elekloader <elekloader checkout> \
    --stock-dt <Digitakt_OS1.54.syx> \
    --stock-dn <Digitone_OS1.44.syx> \
    --toolchain-bin <m68k-elf bin>

The script builds the two 1.3 elemods, lints and patch-checks both, stages them in releases/elemods/, writes local test .syx files under out/, and creates releases/DigiFilter-1.3.zip. Override the cores with --core-dt / --core-dn if they live elsewhere.

Install with elekloader: add your stock OS, the matching core and the elemod, then build the custom .syx and flash it with Elektron Transfer.

Device notes

• Digitakt mk1 — DigiFilter
• Digitone mk1 / Keys — DigiFilter-DN

Testing

# Digitakt DSP
python tests/filter_model.py
python tests/comb_equivalence.py
python tests/ob1_table_accuracy.py
python tests/df_bench.py          # needs digiemu's patched Unicorn

# Digitone: builds and runs the shared DigiFilter DSP on the host
python tests/df_bench.py          # needs digiemu's patched Unicorn

See the device READMEs and docs/ob1.md for the emulator and hardware checks.

Credits

• Digital Alchemy DSP - the Digitakt DigiFilter modes and the Digitone DigiFilter port, DSP and FLTR-page drawing.
• Simon Johansson - OB4/OB2, the Oberheim OB-1 VCF model.
• x2k_77-m1 - the original Digitone port and TYPE icons.

Licence

GPL-2.0-or-later. No Elektron firmware is included or committed.