Ohmforce — Bohm Multimodal Kick Drum Voice

• Manual PDF

Manual PDF / Source

Bohm Eurorack Cheat Sheet

What it is

Bohm is a stereo dual-voice Eurorack kick module system with optional expanders:

• Bohm main module: kick synthesis engine
• Groove expander: secondary kick / techno rumble / layered percussion
• Performer expander: DJ-style effects, ducking, stereo processing

Size / Installation

• Bohm: 18HP
• Groove: 10HP
• Performer: 8HP

Install with power off, ribbon cable aligned correctly (red stripe orientation matters), then secure without overtightening.

Quick Start

1. Install and power up the module.
2. Select a kick model.
3. Trigger the sound with HIT.
4. Shape the drum using:
5. VELOCITY
6. LENGTH
7. SUSTAIN
8. ATTACK
9. PITCH
10. CURVE
11. TRS DECAY
12. COLOR
13. FX
14. TRS TONE
15. Use:
16. Studio Mode for immediate sound design
17. Live Song Mode for sequenced kick changes
18. Jam Mode for improvised performance

Core Sound Controls

These controls change behavior depending on the selected model.

• HIT — triggers the kick
• VELOCITY — controls impact / hit strength
• LENGTH — overall hit duration
• SUSTAIN — tail/body sustain
• ATTACK — transient sharpness
• PITCH — base drum pitch
• documented range is roughly C1 to C2
• CURVE — pitch envelope/response shape, inspired by 808/909 kick behavior
• TRS DECAY — decay time for transient/resonant section
• COLOR — tonal character / timbre shaping
• FX — effect amount/character
• TRS TONE — tone shaping for transient/resonant section

Because Bohm uses different internal DSP “models,” the exact meaning and feel of each control can vary by model.

Running Modes

• Studio Mode
  Immediate parameter changes; best for production and patch building.

• Live Song Mode
  Sequenced kick changes; optimized for live performance.

• Jam Mode
  Improvisation-focused mode for spontaneous tweaking.

Expanders

Groove

Adds: - secondary kick voice - techno rumbles - layered percussion

Performer

Adds: - DJ-style effects - ducking - stereo processing

Calibration

Use calibration if: - knobs feel inaccurate - CV response seems off - pitch tracking seems wrong

Calibration may include: - knob sweeps - CV checks - optional 3V pitch calibration - separate calibration for Groove and Performer

Firmware Update

Uses the included microSD card.

Update steps

1. Download firmware package
2. Copy contents to the SD card root
3. Reinsert the SD card

4. Power on the Eurorack system

5. Update time: about 20 seconds

Storage / Technical Notes

• microSD / SDHC supported up to 32GB
• Must be FAT32 with MBR
• Stores:
• firmware
• kick models
• samples
• user wavetables
• system settings
• up to 32 programs

I/O and Control Reference

Audio / CV Inputs

Not explicitly listed in the provided manual extract.
The extract mentions calibration of CV inputs, so voltage-controlled inputs exist, but jack names and voltage ranges are not provided in the attached text.

Known from the extract

• CV inputs: present
• Pitch calibration: optional 3V pitch calibration mentioned

Voltage ranges

• CV input ranges: not specified in provided manual text
• Pitch CV reference: 3V calibration point mentioned, but this is not a full operating range specification

Audio / CV Outputs

Not explicitly listed in the provided manual extract.
The module is described as stereo, so stereo outputs are implied, but exact jack names and output voltage levels are not provided in the attached text.

Voltage ranges

• Audio output levels: not specified
• CV output ranges: not specified

Knobs / Buttons / Sliders / Toggles

The attached manual text explicitly names these front-panel controls:

• HIT
• VELOCITY
• LENGTH
• SUSTAIN
• ATTACK
• PITCH
• CURVE
• TRS DECAY
• COLOR
• FX
• TRS TONE

Control type note

The extract does not specify whether each item is a: - knob - button - slider - toggle

However: - HIT is most likely a trigger/performance control - the others are likely parameter controls, typically knobs in Eurorack context

Because the source extract does not state panel hardware types explicitly, these should be treated as named controls, type unspecified.

Practical Use Tips

• Start in Studio Mode to learn how each model responds.
• Treat PITCH + CURVE as the main “character” section for classic kick behavior.
• Use ATTACK and TRS TONE to define click/punch.
• Use LENGTH, SUSTAIN, and TRS DECAY to move from short punchy kicks to long booming tails.
• Use COLOR and FX last for finishing and performance shaping.
• If your pitch or modulation feels wrong, run calibration before troubleshooting the patch.

Missing Details From Provided Extract

The attached text does not include a full jack table. Missing specifics include: - exact input jack names - exact output jack names - trigger/gate input specs - audio output levels - CV input ranges - whether controls have dedicated CV attenuators - exact button/encoder/toggle assignments

If you want, I can also turn this into a compact performance card or a full structured reference table based strictly on the extracted manual text.

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