How to use Karplus-Strong mode on StarLab

StarLab features a Karplus-Strong mode which provides a monophonic, delay-based string synthesizer which can be plucked or bowed like a stringed instrument.

To enter Karplus-Strong mode:

  • Hold the ECHO ON button and turn the DELAY/TUNE knob clockwise until the TAP/TRIG button turns RED.
    • To return to normal delay operation, hold the ECHO ON button and turn DELAY/TUNE knob counterclockwise until the TAP/TRIG button blinks GREEN.

Karplus-Strong Controls

When in Karplus-Strong mode, the DELAY/KARPLUS controls have a different functionality set than in delay mode.

  • TAP/TRIG
    • Press momentarily to trigger or ‘pluck’ the string.
    • Press and hold to continuously excite or ‘bow’ the string.
  • ECHO ON: Mixes in the dry string signal with the WET output.
    • If ECHO ON is not selected, only the reverberated string will be heard at the WET output.
  • FEEDBACK: Affects string decay and structure resonance.
  • DELAY/TUNE: Sets string tuning over a continuous 4 octave range.
    • When SIZE/PITCH CV is detected, it sets fine tuning of 12 semitones.
  • Karplus-Strong Pitch Tracking Adjustment: Adjusts the V/oct tracking to compensate for calibration errors in external control module voltages.
    • Press and hold LOW PASS and turn the INPUT GAIN knob to adjust.
    • Default tracking for accurately calibrated signals is at 12:00. Pitches track flatter at lower settings and sharper at higher settings.

Karplus-Strong CV Inputs

  • SIZE/PITCH CV: Controls the string pitch interval at 1V/octave over a 4 octave range.
    • CV Range: 0-4V
  • TAP/TRIG CV: Triggers or ‘plucks’ the string.
    • CV Range: Rising edge triggered
  • IN GATE CV: Continuously excites or ‘bows’ the string in latching or momentary operation.
    • CV Range: 0-5V