Metronomicon for Disting NT

Metronomicon is a sample-accurate metronome plug-in for the Expert Sleepers Disting NT. It follows MIDI clock, CV clock or its own tempo, counts you in, arms your sampler or looper on the bar line, and adds a polyrhythm layer, 59 rhythm patterns and MIDI drum output, with CV outputs for everything.

Built for playing and recording against a sequencer (e.g. Squarp Hermod+) without relying on quantisation: patch the clock in, press play, hear clicks that sit exactly on the grid.

Contents: Features · Install · Quick start · Manual · Build · Project layout · License

Features

Clock & transport

• Follows MIDI clock (24 PPQN) with Start / Stop / Continue, or clock-only
• Follows CV clock at 24, 4, 2 or 1 PPQN, or one pulse per bar
• Or runs on its own tempo (20–300 BPM) with tap tempo and play/stop on the encoder, a mappable parameter, a gate or a trigger
• Clicks land on the exact sample of a CV edge; subdivisions between clock pulses are interpolated and re-anchored on every pulse, so there's no drift and nothing keeps running on a stale tempo
• Clear status: stopped / waiting / acquiring / running / clock lost / count-in

Metronome

• 11 time signatures with correct beat grouping: 4/4, 3/4, 6/8, 2/4, 12/8, 2/2, 5/4, 7/8, 9/8, 5/8, 7/4
• Clicks on beats, 1/4, 1/8 or 1/16, with distinct downbeat / beat / subdivision sounds and levels
• Two click sounds: Classic (woody) and Soft (lower, drier)
• Toggle the click on/off from a trigger input

Count-in & recording (when Metronomicon is the master clock)

• Count-in of 1–4 bars on its own sound
• Arms samplers and loopers: a record trigger or gate (plus an optional MIDI note) exactly on bar 1; open-ended takes end on the next bar line, or fixed 1–16-bar takes end by themselves
• MIDI clock + Start/Stop out and a Run gate, so other gear follows

Polyrhythm

• Any X:Y from 1–16 against Y quarter notes, plus presets (3:2, 2:3, 3:4, 4:3, 6:4, 5:4, 4:5, 5:3, 7:4, 3:8)
• Accent on the cycle start; its own clock and reset outputs

Rhythm patterns — 59 patterns in 9 groups

• Afro-Cuban/African, Odd meter, Swing/shuffle, Jazz/practice, Indian tala, Middle Eastern, Brazilian, Caribbean, Funk/electronic
• Accents, normal hits and ghost notes; trigger, accent, ghost, velocity-CV and reset outputs

Outputs

• Each layer has its own audio bus, level and on/off; audio mutes never stop CV
• MIDI drum output: every click as a note, per-voice note numbers, velocity from levels
• Every layer keeps its own cycle — a 3:2 polyrhythm or a 6-quarter bell pattern runs against 3/4 without being reset by the bar — and all of them realign on start or reset

Install

1. Download metronomicon.o from Releases.
2. Copy it to /programs/plug-ins/ on the Disting NT's SD card. If you had an older metronome.o, delete it, or both will load.
3. Add the Metronomicon algorithm (Utility category). Its screen shows the version (e.g. v1.10) above the BPM.

Requires Disting NT firmware 1.18 or newer.

Quick start

Follow a CV sequencer (e.g. Hermod+)

1. Sequencer CLOCK OUT (24 PPQN) → NT input 1; RESET OUT → NT input 2.
2. Clock source = CV, CV clock res = 24 PPQN, CV transport = RESET (or RUN if your sequencer sends a run gate). These are the defaults.
3. Press play on the sequencer.

Follow MIDI clock

1. Sequencer or DAW MIDI out → NT MIDI in, sending clock and transport.
2. Clock source = MIDI.
3. Press play on the sequencer.

Be the master clock

1. Clock source = Internal, set Internal BPM (or tap the right encoder).
2. Press the left encoder to play/stop.
3. Optional: MIDI clock out = On and/or patch Run out + Base clock out to slave other gear.

Record a loop with a count-in into a sampler or looper

1. Be the master clock (above). Set Count-in = 1 bar.
2. Patch Rec out to the device's record input; pick Rec out mode = Trigger (press-to-start, press-to-stop devices) or Gate (records while high).
3. Turn on Rec arm and press play: 1 2 3 4, recording starts on bar 1.
4. Press stop (or turn Rec arm off to keep playing): the take ends on the next bar line.

Manual

The display

Status: STOPPED (transport stopped) · WAITING (playing, waiting for the first clock) · ACQUIRING (measuring tempo / finding the bar) · RUNNING · CLOCK LOST (clock stopped arriving while playing) · COUNT-IN.

Encoders (Internal clock only, on the Metronomicon display): left press = play/stop, right press = tap tempo. With MIDI or CV clock they keep their normal function.

Some parameters appear on two pages; they are the same parameter, so changing one changes both. Parameters that don't apply to the current setup are greyed out.

Clock & Transport page

Tap tempo averages up to the last five taps; a gap longer than 2.5 s starts over. The new tempo applies immediately and is written to Internal BPM, so it's saved with the preset.

Count-in & Rec page

Play, Count-in and Count-in clock apply to the Internal clock (Metronomicon as master). Recording and Run out work with any clock source — with MIDI or CV clock, an armed take starts on the next bar line, and stopping the sequencer ends it. MIDI clock out works with the internal or CV clock.

Typical setups:

• Device with no tempo (sampler, looper, recorder): Count-in 1 bar, Rec out to its record input, Rec length Manual or the loop length. Arm, press play.
• Device with a tempo (drum machine, sequencer, DAW): add MIDI clock out and/or Run out
  • Base clock out; set Count-in clock to Run if it needs to lock before bar 1.

Metronome page

Beat grouping

Polyrhythm page

X evenly spaced pulses over Y quarter notes, e.g. 3:4 = three pulses across four beats. The cycle realigns with the beat every Y quarters, independent of the bar.

Ratio and clock-resolution changes take effect at the next cycle boundary, so there are no uneven transition pulses.

Pattern page

Patterns — X accent, x hit, g ghost, . rest. Cycle length in quarter notes.

Notes: odd-meter patterns accent each group start, strongest at the cycle start. Tala: sam = accent, claps = hits, waves (khali) = rests, other counts = ghosts. Middle Eastern: D = accent, T = hit. Several Brazilian and Caribbean entries are reduced guide patterns rather than full arrangements.

Output page

Note velocity follows the voice levels (at defaults: downbeat 127, beat 83, subdivision 32; accents boosted to 127; ghosts ≈ 36). Note-offs follow 15 ms later. Notes are sent with the audio block containing the click.

How timing works

Position is counted at 24 PPQN. Every clock event (MIDI clock, CV edge or internal tick) anchors the timeline; subdivisions, polyrhythm pulses at fractional positions and (swung) pattern steps before the next clock event are scheduled to the sample from the measured clock period. When the next clock arrives, anything pending fires and the timeline re-anchors — no drift, and nothing runs on after the clock stops.

• CV clicks start on the exact sample of the clock edge. MIDI events take effect at the next audio block, because the plug-in API doesn't timestamp MIDI.
• With coarse CV clocks (1 PPQN, 1 per bar) the tempo is unknown until the second pulse, so events in the very first interval fire together on that pulse.
• Clock loss is detected after about 2.5 clock periods (CV) or 4 clock periods (MIDI).
• If the bar position can't be known (e.g. a RUN gate already high when the plug-in loads), the display shows ? and no downbeat accent is played until the next reset or start.
• The internal clock uses a double-precision accumulator: no drift over hours.

Build

Needs the Arm GNU Toolchain (arm-none-eabi) and the Disting NT API at the tag matching your firmware (firmware 1.18 → v1.18.0). A plug-in built against a newer API than the module's firmware shows failed on the plug-ins page.

# macOS / Linux
git clone --branch v1.18.0 https://github.com/expertsleepersltd/distingNT_API.git
make NT_API=distingNT_API          # -> plugins/metronomicon.o
make test                          # host test suite (any C++11 compiler)

# Windows (no make needed): unzip the API next to this folder, then
.\build.ps1

Pushing a tag v* runs the GitHub Actions workflow, which runs the tests, builds metronomicon.o and attaches it to a release.

Patterns are written as strings in tools/gen_patterns.py; run it to regenerate src/patterns.h.

Project layout

src/metronome_engine.h   timing + sound engine (platform-independent, header-only, no allocation)
src/patterns.h           pattern table (generated)
src/metronome.cpp        Disting NT glue: parameters, pages, MIDI, display, custom UI
tests/test_engine.cpp    host test suite with simulated CV/MIDI clocks
tools/gen_patterns.py    readable pattern list -> src/patterns.h
docs/banner.svg / .png   README banner
CHANGELOG.md             version history

License

MIT — see LICENSE.