Ohmforce — Bohm Multimodal Kick Drum Voice


Manual PDF / Source

Bohm Eurorack modulation ideas

Bohm looks much deeper than a simple kick module. Since it’s a stereo dual-voice kick system with different internal models, plus optional Groove and Performer expanders, the best approach is to treat it like a bass/percussion voice rather than only a drum source.

From the manual, the key sound-shaping controls are:

And the important note is that controls behave differently depending on the selected model, so the most interesting results will come from: 1. choosing a model, 2. sending modulation to several parameters at once, 3. using the module’s pitch and decay behavior as the basis for timbre.


General modulation strategy

For Bohm, I’d think in 3 modulation rates:

1. Trigger-rate modulation

Change something every hit: - velocity accents - pitch amount - decay length - color/tone per step

This is how you get alive, animated percussion instead of static kicks.

2. Envelope-rate modulation

Use envelopes to shape timbre over the course of each sound: - short envelope to PITCH for punch - longer envelope to COLOR or FX for evolving body - envelope to SUSTAIN or LENGTH for bass articulation

3. Slow CV / LFO modulation

Use slow movement for atmosphere and instability: - drift TRS TONE - slowly modulate CURVE - stereo movement through FX or Performer processing

This is how you push it into pads, evolving drones, and ominous textures.


1) Distorted percussive sounds

Bohm should be excellent for industrial percussion, smashed kicks, metallic hits, and broken drum machine sounds.

A. Overdriven techno kick variations

Start with a model that already has strong low-end or aggressive transient behavior.

Suggested settings

Modulation patch

What this does

You’ll get kick hits that shift between: - tight thump - crunchy knock - blown-out slam - resonant industrial toms

If the selected model reacts strongly to COLOR or FX, this can get very nasty in a good way.


B. Broken clap/snare-like percussion from a kick engine

Even though Bohm is kick-focused, fast pitch and tone modulation can push it into hybrid percussion.

Patch idea

Result

You can get: - zap-like hits - electro percussion - woody clicks - distorted rim / tom hybrids

If Groove is installed, layer the second voice slightly offset in timing for flammed percussion or rumble tails.


C. FM-like impact sounds

Even without explicit FM in the manual, very fast modulation of pitch-related parameters can fake FM-ish percussion.

Try this

Why it works

The pitch envelope and curve interaction can create: - laser hits - metal punch - tearing impacts - aggressive “speaker rip” attacks

Use a VCA or attenuator because too much pitch envelope will just sound cartoony.


D. Distorted layered percussion with Groove expander

The manual says Groove adds a secondary kick voice for techno rumbles and layered percussion. That means you can design one voice as the transient and the other as the dirt/body.

Layer recipe

Main Bohm voice - short - punchy - more attack - less sustain

Groove voice - lower tuned - longer decay - more color / fx - slightly delayed trigger if possible

Modulation

Result

This gives: - warehouse kick stacks - distorted low tom barrages - rolling industrial grooves - pseudo-reverb rumbles without external effects


2) Crazy basslines for dubstep / drum and bass

This is where Bohm gets really interesting. Since the manual says PITCH ranges roughly from C1 to C2, that’s right in useful bass territory. It won’t be a full-range melodic oscillator in the conventional sense, but for heavy bassline work that limited range can be perfect.

A. Triggered reese-style bass pulses

Use Bohm as a monophonic bass percussion voice rather than a sustained oscillator.

Settings

Modulation

Sound

This should create: - gnarly bass stabs - wobbling low-end phrases - distorted “donk” basses - neuro-ish bass punches

Because Bohm starts from a kick architecture, even pitched notes will retain a percussive front edge, which is excellent for DnB.


B. Dubstep wobble from parameter cross-modulation

Instead of only wobbling filter cutoff like on a subtractive synth, wobble the body mechanics of the kick model.

Core patch

Why this is cool

As COLOR rises while TONE falls, or vice versa, the bass can morph from: - hollow - nasal - snarling - sub-heavy - torn-speaker distorted

This gets you much more unusual movement than a normal filter wobble.


C. Machine-gun bassline growls

Use very short note retriggers with varying pitch envelope depths.

Patch

Target sound

The trick is to make every rapid hit slightly different. Small CV movement on CURVE and COLOR matters a lot.


D. Sub drop / bass cannon patch

Bohm should be able to produce devastating drops if you extend the decay and pitch motion.

Settings

Modulation

Result


E. Fake sidechained bass using Performer

The manual says Performer adds DJ-style effects, ducking, and stereo processing. That is extremely useful for bass design.

Idea

Patch Bohm as both: - your kick/percussive source - and a sustained bass element

Then use Performer’s ducking to carve motion around the attacks.

Outcome

You can get: - self-pumping basslines - club-style movement - huge stereo body with centered attack - more mix-ready distorted low-end

This is especially effective for dubstep intros and halftime grooves.


3) Haunting atmospheric pad sounds

This is the least obvious use, but definitely possible if you stop thinking of Bohm as only a drum.

The manual mentions: - stereo processing - multiple models - FX and tone controls - longer sustain/length options - expanders for wider processing

That suggests Bohm can be pushed into drone and pad-adjacent territory, especially with re-triggering, long decays, and slow modulation.

A. Ghost drone patch

Settings

Modulation

Result

Instead of a punchy kick, you get: - foggy resonant blooms - distant machine drones - haunted engine-room ambience - dark underscoring textures

Add external reverb after Bohm and it becomes much more pad-like.


B. Granular-feeling pad from repeated soft retriggers

Use frequent but low-intensity hits to create a cloud.

Patch

What happens

Each hit becomes a small fragment in a larger texture. In stereo this can feel like: - swarming air - distant choirs of machinery - unstable ambient beds - eerie pulsing fog

This works especially well if the model has a resonant or tonal tail.


C. Dissonant haunted pad using pitch drift

Because Bohm only spans roughly C1 to C2, the pitch range is constrained, which is actually helpful for dark drone work.

Try this

Result

You’ll get subtle beating and tonal ambiguity: - ominous low strings vibe - degraded tape-organ feeling - dark ambient resonance - horror soundtrack undertones


D. Stereo cinematic pad with Performer

Performer’s stereo processing is the key here.

Patch concept

Best use

Even if the source is still obviously “kick-derived,” once spread and effected it can become very atmospheric.


Best parameters to modulate for each goal

For distorted percussion

Prioritize: - VELOCITY - ATTACK - CURVE - COLOR - TRS TONE

These shape the impact and harmonic aggression.

For basslines

Prioritize: - PITCH - CURVE - SUSTAIN - LENGTH - COLOR - FX

These shape note identity, weight, and movement.

For pads/drones

Prioritize: - LENGTH - SUSTAIN - COLOR - FX - TRS TONE - subtle PITCH

These shape resonance, tail, width, and slow transformation.


Advanced modulation ideas

1. Macro modulation

Use one CV source multed to several destinations with different attenuations: - positive to COLOR - inverted to TRS TONE - slight amount to CURVE

One knob or one LFO can then create major morphs.

2. Accent-dependent timbre

Instead of only accenting loudness, use accent gates/CV to also open: - ATTACK - COLOR - FX

That makes accented steps brighter, harsher, and more explosive.

3. Probability-based mutation

Use a probabilistic trigger or random stepped CV to occasionally alter: - PITCH - LENGTH - TRS DECAY

This makes loops feel less repetitive and more performative.

4. Audio-rate abuse

If Bohm accepts sufficiently fast CV on certain inputs, try audio-rate modulation of: - PITCH - COLOR - TRS TONE

Even if it doesn’t behave like clean FM, aliasing and instability can create brutal digital textures.

5. Resampling workflow

Since the module uses microSD / SDHC and stores models/samples/settings, a practical approach is: - patch extreme sounds - record long improvisations - resample the best moments - use those snippets in a sampler for further composition

That’s often the fastest path to truly unique bass and atmospheric material.


Performance mode suggestions

The manual mentions: - Studio Mode - Live Song Mode - Jam Mode

Studio Mode

Use this for: - dialing exact sweet spots - calibrating modulation depth - building resampling material

Live Song Mode

Use this for: - sequenced parameter changes - switching kick/bass character per section - structured bassline or drum evolution

Jam Mode

Use this for: - improvised macro modulation - live tweaking of color/fx/tone - chaotic transitions and fills

For your goals, Jam Mode sounds especially promising for discovering weird bass and haunted textures.


Practical patch recipes

Recipe 1: Industrial broken kick

Recipe 2: Dubstep growl stab

Recipe 3: Neuro percussion fill

Recipe 4: Haunted drone bed

Recipe 5: Bass cannon transition


Final advice

The big takeaway from the manual is that Bohm is model-based, and controls react differently per model, so the deepest sound design move is not just modulating more CV, but finding which model turns a given parameter into something extreme.

If I were designing the kinds of sounds you want, I’d explore in this order:

  1. Find 2–3 aggressive models for distorted percussion
  2. Find 2 models with the strongest tonal sustain for basslines
  3. Find 1–2 resonant/atmospheric models for drone and pad work
  4. Patch:
  5. envelope to PITCH
  6. LFO to COLOR
  7. inverted LFO to TRS TONE
  8. stepped random to VELOCITY or CURVE
  9. Use Groove for layered rumble/body
  10. Use Performer for stereo movement, ducking, and live destruction

That combination should get you well beyond “kick drum” territory and into: - mangled industrial percussion - dubstep and DnB bass assaults - eerie cinematic atmospheres

Generated With Eurorack Processor