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Set up MIDI I/O

skulpton talks directly to OS-level MIDI ports. Each track has its own OUT (send) and IN (receive) routing.

MIDI fields on the track header

Section titled “MIDI fields on the track header”

Each track header has two rows of dropdowns.

RowLeft (port)Right (channel)
OUTDestination MIDI portSend channel 1 to 16
INSource MIDI portReceive channel filter

You can edit the same fields in the per-track settings modal opened with the gear button.

OUT — send port and channel

Section titled “OUT — send port and channel”

Port dropdown:

  • All — send to every open port (default). Convenient when you “just want sound”.
  • Off — this track sends nothing (effectively muted).
  • Device name — send to a specific port only (e.g. IAC Bus 1, USB MIDI Device).

Pick a channel from 1 to 16 to match the receiving synth.

IN — receive port and channel

Section titled “IN — receive port and channel”

Used for live recording or to take input from an external sequencer.

  • Set Port to anything except None
  • Set Channel to All (Omni) or 1 to 16

Conditions for live recording

Section titled “Conditions for live recording”

Recording from IN happens when all of these are true:

  1. The track’s IN port is not None
  2. The track’s Arm button is ON
  3. Record is pressed (the first track is auto-armed if no track is armed)
  4. The incoming MIDI’s channel matches the IN channel filter (or All)

Enable IAC on macOS (app-to-app routing)

Section titled “Enable IAC on macOS (app-to-app routing)”

To MIDI-route from skulpton into another DAW or soft synth, use the macOS-built-in IAC driver.

  1. Open Audio MIDI Setup (Spotlight: “Audio MIDI”)
  2. Window -> Show MIDI Studio
  3. Double-click IAC Driver
  4. Check “Device is online”
  5. Make sure at least one port exists (use + to add one if needed)
  6. Restart skulpton — IAC Bus 1 and friends should appear in the OUT / IN dropdowns

Make a loopback on Windows

Section titled “Make a loopback on Windows”

Windows lacks a built-in loopback, so use a virtual MIDI cable tool such as loopMIDI.

  1. Install and run loopMIDI
  2. Type a port name and press + to add it (e.g. loopMIDI Port)
  3. Restart skulpton — the port appears in the OUT / IN dropdowns

Connect an external hardware synth

Section titled “Connect an external hardware synth”

Connect via USB-MIDI or a MIDI interface:

  1. Make sure the OS sees the device (macOS: Audio MIDI Setup / Windows: Device Manager)
  2. Launch (or restart) skulpton so it rescans
  3. Pick the device name in the track’s OUT
  4. Set the channel to match the synth’s receive channel

Troubleshooting

Section titled “Troubleshooting”

Port not in the dropdown

Section titled “Port not in the dropdown”
  • skulpton enumerates MIDI ports once at launch. Devices added afterwards (or new IAC / loopMIDI ports) only appear after restarting the app.
  • Make sure the virtual MIDI driver (IAC / loopMIDI) actually exposes a port.

Stuck notes

Section titled “Stuck notes”

This is normally suppressed automatically on path changes, but if it ever happens, press Stop — skulpton sends CC123 (All Notes Off) + CC120 (All Sound Off) to all ports on all 16 channels. See Troubleshooting.

Configured but no sound

Section titled “Configured but no sound”
  • Is OUT set to Off?
  • Does the send channel match the synth’s receive channel?
  • Is the track Mute’d?
  • Is another track Solo’d?
  • Is Transport actually playing? (Pause only sounds notes at the playhead.)
Section titled “Related”