What You Need
- A Korg volca FM2 for full two-way SysEx (send, play, and read memory), or a DX7-compatible synth — DX7, TX7, TX802, or the original Volca FM — for send-only patch loading.
- A class-compliant USB-MIDI connection, or a Bluetooth MIDI interface paired through your device's own Bluetooth settings first. On phones and tablets, USB may need a USB-OTG adapter.
- The instrument powered on.
Getting Connected
- Power on the instrument and connect it over USB, or pair it over Bluetooth MIDI first.
- Open Settings, choose Instrument (Volca FM2 or DX7), pick the correct Output port, and press Connect.
- A Volca FM2 that answers its handshake shows its channel and firmware version; a plain DX7-compatible synth connects straight into send-only mode, since it has nothing to hand back.
- If nothing is found, check the cable and the power, then press RESCAN in Settings. Some USB hubs are unreliable — a direct port is worth trying first.
Troubleshooting
The app can't find the volca FM2 or synth.
Confirm it is powered on and connected with a data USB cable rather than a charge-only one. Open Settings, choose the correct MIDI output port, and press Connect. Some USB hubs are unreliable; try a direct port.
Capture, restore, or "read current patch" is greyed out.
Those need a two-way MIDI connection, which only a Volca FM2 answers. Select a MIDI input port as well as an output in Settings, and check the connection-status indicator.
Auditioning is silent.
Check Keys play in Settings — Volca, App, or Both — and the in-app synth volume. If you expect sound from the hardware, confirm the instrument's own volume and that the MIDI channel matches.
Patches didn't import.
Make sure the files really are DX7-format SysEx (.syx or
.sys) or ZIP archives of them, and that you picked the right
folder or files when asked — Rithmatic always imports through a picker rather
than scanning a fixed folder, so nothing loads until you choose a location.
Files that aren't valid DX7 data are skipped.
A restore warned me before running.
That is deliberate — restoring overwrites all of the instrument's programs and sequences. Capture a fresh snapshot first if you want a way back.
Frequently Asked
Does Rithmatic send my patches anywhere?
No. The app makes no outbound network connections at all — not analytics, not crash reports, nothing. Every patch stays on your device, or goes only to your instrument over USB or Bluetooth MIDI.
What file formats can I import?
Yamaha's DX7 voice format — single voices and 32-voice bulk banks alike, both
the packed 128-byte form and the 155-byte expanded one — as .syx
or .sys files, or ZIP archives containing them.
Does it include the factory ROM banks?
No. Yamaha's factory ROM banks aren't bundled or redistributed; if you have your own copies, Settings' Load ROMs control imports them through the same file picker as any other patch files.
What can I do without the hardware connected?
Browsing, tagging, and organizing the library works with nothing attached, and the Patch Builder's in-app FM engine lets you design and audition new patches without a synth at all. Sending patches, reading device memory, and capturing or restoring snapshots need an instrument connected.
Still Stuck
Write in. Rithmatic is made by one person, and email is the only channel — there is no ticket system and no account you need in order to ask. Contact explains what to include so it can be answered in one reply rather than five.
Not Affiliated with Korg or Yamaha
Rithmatic is an independent app. It is not made, endorsed, or supported by Korg Inc. or Yamaha Corporation. For problems with the instrument itself — firmware, hardware faults, warranty — please contact Korg or your retailer.