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KORG volca fm MIDI CC chart, NRPN and OSC map

The KORG volca fm MIDI implementation: 30 CC, each named, for Claude (MCP), SuperCollider or any OSC app.

Device KORG volca fm
Vendor KORG
OSC prefix /volca_fm
Source πŸŽ›οΈ Derived from an Electra One community preset
Revision per pencilresearch canonical CSV
Upstream electra-preset
Driver file devices/korg/volca_fm.json
Not tested on the device yet

This driver comes from documentation or community data and has not been checked on real hardware. If you own one, a quick test and a pull request promoting it helps everyone β€” see CONTRIBUTING.

How do you control it?

Find the MIDI ports, then start the bridge with this driver:

osc-bridge detect        # prints the ready-to-run line for what is plugged in
osc-bridge run --device devices/korg/volca_fm.json --out-port <N> --in-port <M>

Then send OSC to 127.0.0.1:7777, for example:

osc-bridge osc-send /volca_fm/general/transpose 63

From Claude or any MCP client, the osc-bridge mcp server exposes this driver as volca_fm: ask β€œwhat can the KORG volca fm do?” and it reads this map with list_routes. See the MCP guide.

MIDI CC and NRPN parameters (30)

OSC address CC NRPN (MSB/LSB) Range Nature Section
/volca_fm/general/transpose 40 0–127 continuous General
/volca_fm/general/velocity 41 0–127 continuous General
/volca_fm/general/modulator_attack 42 0–127 continuous General
/volca_fm/general/modulator_decay 43 0–127 continuous General
/volca_fm/general/carrier_attack 44 0–127 continuous General
/volca_fm/general/carrier_decay 45 0–127 continuous General
/volca_fm/general/lfo_rate 46 0–127 continuous General
/volca_fm/general/lfo_pitch_depth 47 0–127 continuous General
/volca_fm/general/algorithm 48 0–127 continuous General
/volca_fm/general/arpeggiator_type 48 0–127 continuous General
/volca_fm/general/arpeggiator_div 50 0–127 continuous General
/volca_fm/transpose 40 0–127 continuous
/volca_fm/attack 42 -63–63 continuous
/volca_fm/attack 44 -63–63 continuous
/volca_fm/rate 46 0–99 continuous
/volca_fm/type 49 0–127 continuous
/volca_fm/velocitty 41 1–127 continuous
/volca_fm/decay 43 -63–63 continuous
/volca_fm/decay 45 -63–63 continuous
/volca_fm/pitch_depth 47 0–99 continuous
/volca_fm/algorithm 48 0–127 continuous
/volca_fm/divider 50 0–127 continuous
/volca_fm/patches 88 0–127 continuous
/volca_fm/chorus 85 0–127 continuous
/volca_fm/stereo_width 86 0–127 continuous
/volca_fm/speed 87 0–127 continuous
/volca_fm/tempo_divider 90 0–127 continuous
/volca_fm/patterns 89 0–127 continuous
/volca_fm/wheel 1 0–127 continuous
/volca_fm/assignation 91 0–127 continuous

Performance MIDI

Notes, pitch bend and any CC are also available: /volca_fm/note/on <note> <velocity>, /volca_fm/cc/<number> <value>, /volca_fm/pitchbend <0-16383>, /volca_fm/program_change <n>.

Limitations

CC/NRPN only. SysEx (preset management, display control, bulk dump/load, vendor-proprietary opcodes) is NOT covered by pencilresearch. To extend this device with SysEx, sniff the vendor editor, add `sysex.header/footer` + `commands` blocks, and use `update_device.md` PR template.

Frequently asked questions

How many parameters of the KORG volca fm can be controlled over MIDI?

SynthHub's map of the KORG volca fm lists 30 MIDI CC parameters, each with its number, range and a readable name; the full chart is on this page.

Can an AI agent like Claude control the KORG volca fm?

Yes: SynthHub's hosted MCP server knows the KORG volca fm's MIDI map, and its browser relay lets the agent send it parameter changes or load a sound, each sound change confirmed by you.