Empress ZOIA (ZOIA firmware 5.41) MIDI CC chart, NRPN and OSC map
The Empress ZOIA MIDI implementation: 4 CC, each named, for Claude (MCP), SuperCollider or any OSC app.
- sourcemaker's documentation
- firmware5.41
- real unitnot yet checked
Not checked on a real Empress ZOIA yet. Own one? Load a sound or send a control, and tell us whether it worked.
- Maker
- Empress
- Version
- ZOIA firmware 5.41 (MIDI CC control article)
- Source
- maker's documentation
- OSC prefix
/zoia
Use 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 empress/zoia.vendor.fw-5.41 --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 zoia: ask “what can the Empress ZOIA do?” and it reads this map with list_routes. See the MCP guide.
MIDI controls
4 controls, each with its number, its range and the name to send
Bypass
| Control | CC | Range | Name to send |
|---|---|---|---|
| Bypass | 60 | discrete | /zoia/bypass |
Remote control
| Control | CC | Range | Name to send |
|---|---|---|---|
| Ui press | 61 | discrete | /zoia/ui/press |
| Ui release | 62 | discrete | /zoia/ui/release |
| Ui rotary turn | 63 | discrete | /zoia/ui/rotary_turn |
Performance MIDI
Notes, pitch bend and any CC are also available: /zoia/note/on <note> <velocity>, /zoia/cc/<number> <value>, /zoia/pitchbend <0-16383>, /zoia/program_change <n>.
Limitations
Sources: Empress support article on MIDI CC control (2025-03-19), for firmware 5.41 (the current version), and the 1.13 manual for the rest. On the Config Menu's MIDI channel: CC#60 engages or bypasses, CC#61 and CC#62 press and release any button, stompswitch or the rotary switch (so the whole interface can be driven remotely), CC#63 turns the rotary; Program Change loads that patch (0-63; use /program_change). The article does not say which firmware first had CC#61-63 (the published changelog stops at 5.00, which does not mention them); 5.41 is the version the support pages offer now. Everything else lives in each patch: MIDI modules and starred parameters (learned CCs on the Starred CC ch); reach them with /note/on, /note/off and /cc/{num}. No SysEx. Applies to the ZOIA and the Euroburo, which run the same firmware. Untested on hardware.
Firmwares
The Empress ZOIA runs 2 firmwares SynthHub maps, each with its own MIDI or another's it shares. All the devices with several: firmwares.
| Firmware | From | Licence | MIDI | Sounds |
|---|---|---|---|---|
| ZOIA firmware 5.41 | empresseffects.com | its own | ||
| ZOIA manual, firmware 1.13 | empresseffects.com | its own |
Frequently asked questions
How many parameters of the Empress ZOIA can be controlled over MIDI?
SynthHub's map of the Empress ZOIA lists 4 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 Empress ZOIA?
Yes: SynthHub's hosted MCP server knows the Empress ZOIA's MIDI map, and its browser relay lets the agent send it parameter changes or load a sound, each sound change confirmed by you.