Swarm Core
Bio-acoustic sample engine playing recorded insects. The bank is InsectSet32 — cicadas and orthoptera, field recordings rather than synthesis — and Swarm Core plays them in one of two ways. Specimen mode fires a single pitched voice per trigger. Swarm mode fires up to eight, scattered in time, detuned against each other and spread across a fixed stereo field, which turns individual calls into a chorus.
It is the only module in the plugin that reads files from disk, and that has two consequences worth knowing before you patch it.
- Add Swarm Core. Wait 2–5 seconds. The bank loads on a background thread and the module outputs silence until it finishes — the ACTIVE LED lights when it is ready.
- Patch a clock into TRIG, and OUT L/OUT R to your interface.
- Defaults are SPECIMEN 0, DENSITY 50%, SCATTER 10%, DETUNE 20%, DECAY 50%, in Specimen mode. Each trigger plays one insect call.
- Sweep SPECIMEN while triggering. You are scrolling through the bank, one recording at a time.
- Press MODE. The SWARM LED lights and each trigger now fires several voices — raise DENSITY for more of them, SCATTER to spread them in time, DETUNE to spread them in pitch.
If the sample folder is missing, Swarm Core falls back to a noise burst rather than going silent. If it sounds like noise instead of insects, the bank did not load — check that
res/insects/insectset32/came with your install.
[background thread] load up to 64 WAVs from res/insects/insectset32/
ACTIVE LED dark, output silent, 2–5 s
bank ready → safe to read from the audio thread
TRIG IN (rising edge) ──► fire
V/OCT IN ──────────────► pitch offset in semitones, added to PITCH
SPECIMEN mode:
one voice · sample = bank[SPECIMEN × bankSize]
speed = 2^(semitones/12) × (bankRate / hostRate)
× envelope shaped by DECAY
SWARM mode:
up to 8 voices, fired in succession with SCATTER delays
voice i: speed × 2^(DETUNE × offset[i] / 12)
fixed pan spread: −1, −0.71, −0.33, 0, 0, 0.33, 0.71, 1
active voices = ceil(DENSITY × 8)
│
mix × 1/√8 ─┴──► OUT L / OUT R
envelope sum ───► CV OUT (0–10 V)
| Control | Range | Default | What it does |
|---|---|---|---|
| SPECIMEN | 0–100% | 0 | Sample select, mapped linearly across the loaded bank |
| PITCH | −24 to +24 st | 0 | Playback pitch offset. 0 plays at the original rate |
| DENSITY | 0–100% | 50% | Swarm voice count, 1 to 8. Ignored in Specimen mode |
| SCATTER | 0–100% | 10% | Timing spread between swarm voices. 0 fires them together |
| DETUNE | 0–100% | 20% | Per-voice pitch spread in Swarm mode |
| DECAY | 0–100% | 50% | Playback envelope. Low fades fast; high plays the full sample |
| MODE | button | Specimen | Toggles Specimen / Swarm. The SWARM LED shows the state |
PITCH, DENSITY, SCATTER and DETUNE have attenuverters and CV inputs. DECAY has a CV input but no attenuverter — its CV adds directly to the knob. SPECIMEN and MODE have neither.
| Port | Direction | Notes |
|---|---|---|
| TRIG | Input | Rising edge fires. In Swarm mode it fires every active voice, with scatter |
| V/OCT | Input | Pitch offset, added to the PITCH knob |
| DENSITY / SCATTER / DETUNE CV | Input | Via their attenuverters |
| DECAY CV | Input | Added directly to the knob — no attenuverter on this one |
| OUT L / OUT R | Output | Stereo, 1/√8 normalised |
| CV OUT | Output | Summed voice envelope, 0–10 V |
CV OUT is the useful oddity here: it is an envelope follower on Swarm Core's own output, so the swarm can drive other modules in time with itself.
- InsectSet32, Zenodo 7072196, CC-BY 4.0.
- Cicadidae (cicadas) and orthoptera (crickets, grasshoppers, katydids).
- Up to 64 WAV files loaded from
res/insects/insectset32/, recursively, sorted. - 16-bit or float32 PCM, mono or stereo. Stereo files are read as mono from the left channel.
- Maximum 5 seconds loaded per sample.
Single cicada. Specimen mode, DECAY 70%, triggered from Drift GATE at RATE 15%. One call at irregular intervals — presence rather than rhythm.
Cricket chorus. Swarm mode, DENSITY 80%, SCATTER 15%, DETUNE 30%, DECAY 60%, on a steady clock. A dense field that still reads as individual insects.
Storm swarm. Swarm mode, DENSITY 100%, SCATTER 40%, DETUNE 60%, DECAY 40%, triggered on eighth notes. Eight voices, widely scattered — no longer identifiable as insects.
Pitched texture. Specimen mode, Harmonic-Pressure V/OCT OUT → V/OCT IN, DECAY 80%. The same recording plays at several harmonic partials at once and stops sounding like a field recording.
Self-modulation. CV OUT → SCATTER CV or Collapse-Saturator SIDECHAIN. The swarm's own envelope drives what happens to it.
Locked to the grid. Pulse and Swarm Core on one clock. Percussion and insects land together; PITCH at +12 st separates them in register.
| Module | Routing |
|---|---|
| Pulse | Share a clock, or take Pulse's grid as the trigger source |
| Drift | GATE → TRIG for stochastic calls; SMOOTH → SCATTER for drifting spread |
| Harmonic-Pressure | V/OCT → V/OCT IN for pitched harmonic texture |
| Choke | OUT L/R into channels, alongside the drone layers |
| Collapse-Saturator | OUT → IN, or CV OUT → SIDECHAIN for self-driven distortion |
| Wall-Conductor | OUT → a channel as an environmental layer under the wall |
Pulse · Drift · Sitar-Grid · Playbooks
Sample bank: InsectSet32 — CC-BY 4.0.
Full parameter spec: docs/modules/SwarmCore.md