MFB Synth II MIDI CC chart, NRPN and OSC map¶
The MFB Synth II MIDI implementation: 34 CC, each named, for Claude (MCP), SuperCollider or any OSC app.
| Device | MFB Synth II |
|---|---|
| Vendor | MFB |
| OSC prefix | /synth_ii |
| Source | 📦 Derived from MIDI Guide (community CC/NRPN data) |
| Firmware | unknown |
| Revision | per pencilresearch canonical CSV |
| Upstream | pencilresearch |
| Data licence | CC-BY-SA-4.0 — MIDI Guide (https://midi.guide) by Pencil Research and contributors |
| Driver file | devices/mfb/synth_ii.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 — 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/mfb/synth_ii.json --out-port <N> --in-port <M>
Then send OSC to 127.0.0.1:7777, for example:
From Claude or any MCP client, the osc-bridge mcp server exposes this driver as synth_ii: ask “what can the MFB Synth II do?” and it reads this map with list_routes. See the MCP guide.
MIDI CC and NRPN parameters (34)¶
| OSC address | CC | NRPN (MSB/LSB) | Range | Nature | Section |
|---|---|---|---|---|---|
/synth_ii/general/glide |
5 | 0–127 | continuous | General | |
/synth_ii/general/mod_vco |
6 | 0–127 | continuous | General | |
/synth_ii/oscillators/pulse |
8 | 0–127 | continuous | Oscillators | |
/synth_ii/lfo/rate1 |
9 | 0–127 | continuous | LFO | |
/synth_ii/oscillators/interval_1 |
10 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/interval_2 |
11 | 0–127 | continuous | Oscillators | |
/synth_ii/lfo/rate2 |
12 | 0–127 | continuous | LFO | |
/synth_ii/mix/level_vco1 |
13 | 0–127 | continuous | Mix | |
/synth_ii/mix/level_vco2 |
14 | 0–127 | continuous | Mix | |
/synth_ii/mix/level_vco3 |
15 | 0–127 | continuous | Mix | |
/synth_ii/mix/level_noise |
16 | 0–127 | continuous | Mix | |
/synth_ii/mix/audio_in |
17 | 0–127 | continuous | Mix | |
/synth_ii/general/mod_vcf |
18 | 0–127 | continuous | General | |
/synth_ii/general/mod_vca |
19 | 0–127 | continuous | General | |
/synth_ii/filter/keyfollow |
20 | 0–127 | continuous | Filter | |
/synth_ii/filter/cutoff |
21 | 0–127 | continuous | Filter | |
/synth_ii/filter/emphasis |
22 | 0–127 | continuous | Filter | |
/synth_ii/filter/contour |
23 | 0–127 | continuous | Filter | |
/synth_ii/envelopes/attack1 |
24 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/decay1 |
25 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/sustain1 |
26 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/release1 |
27 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/attack2 |
28 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/decay2 |
29 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/sustain2 |
30 | 0–127 | continuous | Envelopes | |
/synth_ii/envelopes/release2 |
31 | 0–127 | continuous | Envelopes | |
/synth_ii/oscillators/octave1 |
80 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/wave1 |
81 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/octave2 |
82 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/wave2 |
83 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/octave3 |
84 | 0–127 | continuous | Oscillators | |
/synth_ii/oscillators/wave3 |
85 | 0–127 | continuous | Oscillators | |
/synth_ii/lfo/wave_mod1 |
86 | 0–127 | continuous | LFO | |
/synth_ii/lfo/wave_mod2 |
87 | 0–127 | continuous | LFO |
Performance MIDI¶
Notes, pitch bend and any CC are also available: /synth_ii/note/on <note> <velocity>, /synth_ii/cc/<number> <value>, /synth_ii/pitchbend <0-16383>, /synth_ii/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¶
Which MIDI CC controls the filter cutoff on the MFB Synth II?
CC 20 (0–127), named /synth_ii/filter/keyfollow in SynthHub's map.
How many parameters of the MFB Synth II can be controlled over MIDI?
SynthHub's map of the MFB Synth II lists 34 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 MFB Synth II?
Yes: SynthHub's hosted MCP server knows the MFB Synth II's MIDI map, and its browser relay lets the agent send it parameter changes or load a sound, each sound change confirmed by you.