chompi-hmmm

Beta. Tested on one CHOMPI so far, so back up your card first.

HMMM is a drone machine for the CHOMPI, inspired by the SOMA Lyra-8:

• eight voices, triangle to square, each tuned by ear;
• pairs that frequency-modulate each other in a ring;
• a Hyper LFO, and TOTAL FB, where the output modulates itself;
• a two-line modulated delay that can sing on its own, then a fuzz.

Runs on its own like any stock CHOMPI firmware, or on the multi-firmware launcher card next to TAPE, TEMPO, WAVE and POLY.

Install

Download chompi-hmmm-beta.zip below.

On its own: copy HMMM.bin to the root of the card, as the only .bin there (remove CHOMPI.bin or any other). Power on. The rainbow shows while it installs.

On the launcher: copy HMMM.bin into /FIRMWARE. It goes on the first free key, or name it e.g. 06_HMMM.bin for key 6.

HMMM makes a /HMMM folder on the card for your patches.

Quick start

The CHOMPI key (red, top left) is SHIFT.

1. Hold white keys 1–8. Each voice swells in and fades slowly when you let go. Voices 1–2 are low, 3–6 middle, 7–8 high.
2. LOOP latches: tap a voice on, tap it off.
3. Big purple dial: delay feedback. Past the middle it turns white and the delay keeps singing on its own.
4. Volume knob: volume. Shift + turn sets distortion drive. Click: everything off.
5. Toggle switch: how the voices FM each other. Up is one big loop, down is two.
6. PLAY: TOTAL FB, chaos. It affects pairs whose MOD source is set to LFO.
7. Patches: shift + white key loads one (1 organ, 2 FM loop, 3 LFO pulse, 4 delay drone, 5 chaos, 6 hold drone, 15 init). Hold for 1 s to save.

Pages: shift + black key

Italics = shift + turn.

#	Page	Knob 1	Knob 2	Knob 3	Knob 4
1	TUNE 1–4	voice 1	voice 2	voice 3	voice 4
2	TUNE 5–8	voice 5	voice 6	voice 7	voice 8
3	SHARP	pair 12 FAST	pair 34 FAST	pair 56 FAST	pair 78 FAST
4	MOD	FM 12 source	FM 34 source	FM 56 source	FM 78 source
5	GROUPS	HOLD 1–4 vibrato	HOLD 5–8	PITCH 1–4	PITCH 5–8
6	HYPER LFO	speed A	speed B	OR / AND	LINK
7	DELAY	mix mod 1	time 1 mod 2	time 2 SELF / LFO	feedback TRI / SQUARE
8	DISTORTION	drive	mix
9	VOICE	attack	release	character	stereo spread
10	TUNE	octave	transpose	fine	MIDI bend range

What the pages do:

• TUNE pages: a plain turn is fine tuning. Shift + turn moves by semitone.
• MOD source: off, FM (the neighbouring pair), or LFO (the Hyper LFO, or the output when TOTAL FB is on).
• HOLD: makes a group drone by itself, without keys.
• PITCH: moves a whole group, keeping its tuning.
• Shift + click resets a knob.

Known issues

• HOLD is quiet. Turn it most of the way up. Patch 6 drones on its own but is soft and low on the CHOMPI speaker.
• MIDI in is untested. Notes C3–C4 on the white keys play voices 1–8, and most parameters have a CC.

Coming next: a global filter, a pan for each voice, a movable group split, and clearer key lights showing which voices are on.

sha256  578c0b9f30ad17936cf564ebb48c8c99c1cd9ca73f5dc79f2683eb323ed7aa61  HMMM.bin

By hiwatts (@sfaber02). Built on CHOMPI Club's open-source firmware (MIT). An homage to the Lyra-8, not affiliated with SOMA Laboratory. A community firmware, not an official CHOMPI Club release.