# Ohmforce — Bohm Multimodal Kick Drum Voice - [Manual PDF](../../manuals/Bohm_Eurorack_Manual_Compiled.pdf) --- [Manual PDF / Source](https://bohm-eurorack-manual.readthedocs.io/en/latest/index.html) # 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: - **HIT** - **VELOCITY** - **LENGTH** - **SUSTAIN** - **ATTACK** - **PITCH** - **CURVE** - **TRS DECAY** - **COLOR** - **FX** - **TRS TONE** 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 - **ATTACK:** medium to high - **PITCH:** low-mid - **CURVE:** steeper/faster for a hard drop - **LENGTH / SUSTAIN:** short to medium - **COLOR:** push until harmonics emerge - **FX:** increase until it begins to feel unstable or widened - **TRS DECAY / TRS TONE:** tune for resonance or ringing ### Modulation patch - Send a **random stepped CV** to **VELOCITY** - Send a second, attenuated random CV to **COLOR** - Use an accent trigger to open **ATTACK** or increase **HIT** - Modulate **CURVE** every 4 or 8 steps with a sequencer row ### 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 - Set **PITCH** higher than normal kick range - Keep **LENGTH** very short - Increase **ATTACK** - Tune **TRS TONE** to emphasize a noisy or clicky region - Modulate **COLOR** with a very fast envelope - Use small random CV into **PITCH** ### 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 - Mult your trigger: - one copy triggers Bohm - another triggers a very short envelope - Send that envelope to **PITCH** - Send an inverted or attenuated version to **CURVE** - Optionally modulate **TRS TONE** at the same time ### 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 - Sequence different velocities to both voices - Modulate Groove pitch subtly with an LFO or random source - Send occasional longer gates for selective rumble blooms ### 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 - **SUSTAIN:** medium - **LENGTH:** medium-long - **PITCH:** tuned to root note area - **CURVE:** moderate, not too steep - **COLOR:** enough to growl - **FX:** add stereo dirt/motion - **TRS TONE:** find a sweet spot with midrange bite ### Modulation - Sequence pitch changes in a low register - Send an LFO to **COLOR** - Send a different slower LFO or stepped random to **FX** - Use accent CV into **VELOCITY** - Occasionally increase **ATTACK** for selected notes ### 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 - Clock-sync an LFO - Send it to **COLOR** - Send an attenuated inverted copy to **TRS TONE** - Send another divided clock modulation to **FX** - Sequence **PITCH** in a repeating 1–2 bar pattern ### 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 - Rapid trigger pattern from a sequencer - A modulation lane to **VELOCITY** - Another lane to **CURVE** - A burst generator or ratcheting trigger into HIT - Envelope to **PITCH** amount via VCA ### Target sound - stuttering bass attacks - talking growls - tearing fills - jump-up DnB style bass punctuation 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 - **PITCH:** low - **LENGTH / SUSTAIN:** long - **CURVE:** tuned for a dramatic downward sweep - **COLOR:** moderate - **FX:** enough to widen or dirty the tail ### Modulation - Trigger with a long gate - Use a descending envelope to **PITCH** - Slowly open **COLOR** over the tail - If Performer is installed, use its **ducking and stereo processing** around the hit ### Result - festival-style bass drops - trailer impacts - cinematic subs - huge intros and transitions --- ## 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 - **LENGTH / SUSTAIN:** high - **ATTACK:** softened if possible - **PITCH:** low-mid - **CURVE:** gentle - **COLOR:** low to medium - **FX:** moderate to high - **TRS TONE:** tuned for a hollow or mournful resonance ### Modulation - Very slow LFO to **PITCH** (tiny depth) - Separate slow LFO to **COLOR** - Random smooth CV to **TRS TONE** - Sparse triggers or manually tapped HIT ### 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 - Send a fast but irregular trigger stream - Lower **VELOCITY** - Lengthen **SUSTAIN** - Keep **ATTACK** modest - Slowly modulate **FX** and **TRS TONE** ### 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 - Tune the main pitch to the root - Send tiny random or sample-and-hold modulation to **PITCH** - Use another slow modulation to **CURVE** - Increase **FX** for width or instability - Layer Groove at an interval-like offset if possible ### 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 - Long-decay Bohm sound - Sparse triggers - Slow CV to timbral parameters - Use Performer for width, ducking, and DJ-style effects ### Best use - huge intro washes - breakdown textures - transitions between heavy sections - hovering stereo dread 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 - 4-on-the-floor trigger into HIT - random CV to VELOCITY - short envelope to PITCH - sequencer row to COLOR - occasional accent to ATTACK - Groove layer with long rumble tail ## Recipe 2: Dubstep growl stab - melodic trigger sequence - tune PITCH to root/fifth - medium sustain - synced LFO to COLOR - inverted LFO to TRS TONE - stepped modulation to FX - Performer ducking for pump ## Recipe 3: Neuro percussion fill - ratcheting triggers - short decay - modulate CURVE every step - random CV to PITCH at low depth - high COLOR and aggressive FX - automate mutes for sudden drops ## Recipe 4: Haunted drone bed - sparse triggers - long sustain/length - slow LFO to COLOR - random smooth CV to TRS TONE - tiny pitch drift - stereo processing from Performer - external reverb after output ## Recipe 5: Bass cannon transition - one trigger every 8 or 16 bars - long pitch envelope downward - long sustain - increase FX over tail - optional Groove layer for sub reinforcement - Performer widening on tail only --- # 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: - envelope to **PITCH** - LFO to **COLOR** - inverted LFO to **TRS TONE** - stepped random to **VELOCITY** or **CURVE** 5. Use **Groove** for layered rumble/body 6. 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](https://github.com/nstarke/eurorack-processor)