Strumboli

Turn your drawing tablet into a MIDI strumming controller

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Control MIDI velocity and note dynamics

Note Velocity

Controls MIDI velocity (note loudness/dynamics) based on tablet input. Velocity is one of the most important parameters for expressive performance.

Settings

control

Type: string
Default: "pressure"
Options: "pressure", "tiltX", "tiltY", "tiltXY", "xaxis", "yaxis"
Description: Which tablet input controls velocity

Examples:

{
  "noteVelocity": {
    "control": "pressure"
  }
}

"pressure" is the most natural mapping for dynamics.

min

Type: integer
Default: 0
Range: 0-127
Description: Minimum MIDI velocity

Examples:

{
  "noteVelocity": {
    "min": 20
  }
}

Setting above 0 ensures notes are always audible.

max

Type: integer
Default: 127
Range: 0-127
Description: Maximum MIDI velocity

Examples:

{
  "noteVelocity": {
    "max": 100
  }
}

Reduce if notes are too loud at full pressure.

default

Type: integer
Default: 64
Range: 0-127
Description: Default velocity when control is neutral

Examples:

{
  "noteVelocity": {
    "default": 64
  }
}

curve

Type: float
Default: 1.0
Range: > 0
Description: Response curve shape

Values:

  • 1.0 - Linear (no curve)
  • 2.0 - Gentle curve
  • 3.0 - Moderate curve
  • 4.0 - Steep curve (very sensitive at low end)
  • 0.5 - Compressed (reduces low-end sensitivity)

Examples:

{
  "noteVelocity": {
    "curve": 4.0
  }
}

Note: For velocity, curve: 4.0 with spread: "direct" creates very expressive light-touch dynamics.

spread

Type: string
Default: "direct"
Options: "direct", "inverse", "central"
Description: How input maps to output range

Values:

  • "direct" - 0 → min, 1 → max (light = quiet, hard = loud)
  • "inverse" - 0 → max, 1 → min (light = loud, hard = quiet)
  • "central" - 0.5 → default, edges → min/max

Examples:

{
  "noteVelocity": {
    "spread": "direct"
  }
}

multiplier

Type: float
Default: 1.0
Range: > 0
Description: Overall scale factor applied to final value

Examples:

{
  "noteVelocity": {
    "multiplier": 1.5
  }
}

Multiplies the final velocity after all other calculations.

Configuration Example

{
  "noteVelocity": {
    "min": 0,
    "max": 127,
    "default": 64,
    "multiplier": 1.0,
    "curve": 4.0,
    "spread": "direct",
    "control": "pressure"
  }
}

Curve Values for Different Feels

  • Linear (1.0): Predictable, technical control
  • Gentle (2.0): Slight enhancement, natural feel
  • Moderate (3.0): Good balance of control and expression
  • Steep (4.0): Very expressive, great for velocity

Common Control Mappings

Control Best For
pressure Velocity, dynamics
tiltX Alternate expression control
tiltY Alternate expression control
tiltXY Combined tilt magnitude
yaxis Position-based dynamics
xaxis Less common for velocity

Related Documentation