Strumboli

Turn your drawing tablet into a MIDI strumming controller

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Connect MIDI keyboards and controllers

MIDI Input

Configure Strumboli to receive MIDI input from keyboards or controllers, allowing you to combine keyboard note selection with tablet expression.

midiInputId

Type: string or null
Default: null
Description: MIDI input device name for receiving keyboard input

When configured, Strumboli listens to the specified MIDI device for note messages. The incoming notes determine which notes are strummed when you use the tablet.

How It Works

Normal Mode (No MIDI Input)

  1. Tablet buttons select chords
  2. Tablet strumming plays those chord notes
  3. Expression comes from tablet (pressure, tilt, position)

MIDI Input Mode

  1. MIDI keyboard selects which notes to play
  2. Tablet strumming triggers those notes
  3. Expression still comes from tablet (pressure, tilt)

This gives you the best of both worlds: keyboard note selection + tablet expression!

Configuration

Disable MIDI Input (Default)

{
  "startupConfiguration": {
    "midiInputId": null
  }
}

Enable MIDI Input

{
  "startupConfiguration": {
    "midiInputId": "Launchkey MK4 25 MIDI Out"
  }
}

Finding your device name:

  1. Run Strumboli without midiInputId set
  2. Check console output for available MIDI devices
  3. Copy exact device name into configuration
  4. Restart Strumboli

Use Cases

Piano-Style Performance

Play chords on keyboard, strum with tablet for dynamics:

{
  "startupConfiguration": {
    "midiInputId": "Digital Piano MIDI Out"
  },
  "noteVelocity": {
    "control": "pressure",
    "curve": 4.0
  }
}

Bass Lines

Play bass notes on keyboard with tablet expression:

{
  "startupConfiguration": {
    "midiInputId": "MIDI Controller",
    "strumming": {
      "upperNoteSpread": 0,
      "lowerNoteSpread": 1
    }
  }
}

Melody with Expression

Keyboard for melody, tablet for articulation:

{
  "startupConfiguration": {
    "midiInputId": "MIDI Keyboard"
  },
  "noteDuration": {
    "control": "yaxis",
    "min": 0.1,
    "max": 2.0
  },
  "pitchBend": {
    "control": "tiltX"
  }
}

Common MIDI Devices

MIDI Keyboards

  • Novation Launchkey series
  • Arturia KeyLab series
  • M-Audio Keystation series
  • Roland A-series
  • Native Instruments Komplete Kontrol

MIDI Controllers

  • AKAI MPK Mini
  • Novation Launchpad
  • Arturia BeatStep
  • Korg nanoKEY

Virtual MIDI

  • macOS: IAC Driver (Audio MIDI Setup)
  • Windows: loopMIDI, MIDI-OX
  • Linux: ALSA virtual ports

MIDI Input Behavior

Note On Messages

  • Single note: Plays that note with tablet expression
  • Multiple notes (chord): Plays all notes simultaneously
  • Note spread: Affected by upperNoteSpread and lowerNoteSpread settings

Note Off Messages

  • Releases notes based on noteDuration settings
  • Can be overridden by tablet release

Velocity

  • MIDI velocity is ignored by default
  • Tablet pressure controls velocity via noteVelocity settings
  • This allows consistent dynamics regardless of keyboard touch

Sustain/Hold Pedal

  • Hold pedal extends note duration
  • Overrides noteDuration settings while held
  • Notes release when pedal is released

Configuration Examples

Simple Keyboard Input

{
  "startupConfiguration": {
    "midiInputId": "USB MIDI Keyboard"
  }
}

Keyboard + Tablet Buttons

{
  "startupConfiguration": {
    "midiInputId": "MIDI Keyboard"
  },
  "tabletButtons": {
    "1": ["transpose", 12],
    "2": ["transpose", -12],
    "3": "toggle-repeater"
  }
}

Virtual MIDI from DAW

{
  "startupConfiguration": {
    "midiInputId": "IAC Driver Bus 1"
  }
}

Troubleshooting

Device Not Found

  1. Check device is connected and powered on
  2. Verify device name spelling (case-sensitive)
  3. Check Strumboli console output for available devices
  4. Try disconnecting and reconnecting device
  5. Restart Strumboli after connecting device

No Notes Triggering

  1. Verify MIDI input is connected
  2. Check midiInputId matches device name exactly
  3. Test device in another MIDI application
  4. Look for error messages in console
  5. Verify MIDI channels match (if applicable)

Notes Stuck

  1. Press keys again to send Note Off
  2. Check for MIDI feedback loops
  3. Restart Strumboli
  4. Disconnect and reconnect MIDI device

Wrong Notes Playing

  1. Verify upperNoteSpread and lowerNoteSpread settings
  2. Check transpose settings
  3. Ensure correct MIDI octave on keyboard
  4. Test with simple single notes first

Advanced: Virtual MIDI Setup

macOS

  1. Open Audio MIDI Setup
  2. Window → Show MIDI Studio
  3. Double-click IAC Driver
  4. Check "Device is online"
  5. Use "midiInputId": "IAC Driver Bus 1"

Windows (loopMIDI)

  1. Download and install loopMIDI
  2. Create new virtual port
  3. Use that port name in midiInputId

Linux (ALSA)

# Create virtual port
aconnect -l
# Note port numbers, then:
aconnect [source] [destination]

Related Documentation