SuperKar+

SuperKar+ is a voice module based on Karplus-Strong synthesis, a technique that generates pitched sounds by running noise or transients through a very short delay line with feedback. The module offers 32 voices of polyphony split between two independent channels: a Solo Voice and a Chord Voice. The Solo Voice handles melodies and accepts polyphonic MIDI input, while the Chord Voice generates harmonies from a single pitch CV using selectable scales (like Dorian, Lydian, and Harmonic Minor, etc.). Both channels can run simultaneously or independently, and each has its own timbre setting — positive feedback for string-like tones, negative feedback for hollow pipe and tube sounds.

The synthesis itself feels almost alive — there are three main parameters that shape the sound: Attack controls the excitation character from sharp plucks to sustained bows, Decay sets how long the resonance rings, and Damp functions like palm-muting by affecting the feedback structure. All three parameters are CV-controllable. The Solo Voice includes a Detune function that adds random pitch variance per note, useful for creating ensemble-style width or unstable textures. The Chord Voice’s Harmony control offers 15 settings from simple octave doubling to complex intervallic structures with smart scale-aware voicings. Additional performance controls include Glide for portamento, a Pitch CV input for vibrato or modulation, and the ability to use external audio as an exciter for the delay lines. Plenty of options, let’s leave it at that…!

Output routing covers multiple configurations: wide or narrow stereo spread, split mode that sends Solo Voice to the left output and Chord Voice to the right, or mono sum to both outputs. Because the synthesis method includes its own amplitude envelope, SuperKar+ functions as a complete voice without requiring external VCAs. The module provides CV inputs for most parameters and features Strymon’s typical clean panel layout with secondary functions accessed via an Alt button. There aren’t a whole lot of Karplus-Strong modules for Eurorack out there, and this one especially has plenty on offer. In case that’s what you’ve been hunting for, you can finally end your search 🙂

Features:

• Karplus-Strong synthesis with two independent polyphonic voices (Solo Voice and Chord Voice)
• 32 total voices (16 per channel)
• Six-octave range with stable pitch tracking
• Solo Voice: MIDI control with velocity sensitivity, up to 16-note polyphony
• Chord Voice: Root-based chord generation with 15 harmony settings
• Eight selectable scale types (Major, Dorian, Lydian, Phrygian, Aeolian, Harmonic Minor, Expanded Voicing Major, All Major Chords)
• Dual timbre modes per voice: positive feedback (strings) / negative feedback (pipes and tubes)
• CV control over Attack, Decay, Damp, Pitch, Detune (Solo), and Harmony (Chord)
• Detune function for random per-note pitch variance
• Variable Glide (portamento) per voice
• Four output configurations: Wide Stereo, Narrow Stereo, Split Voices, Mono Sum
• 520MHz ARM Superscalar processor with 32-bit floating-point processing
• Audio inputs for external signal excitation and sympathetic resonance
• Tune control with quantize option (continuous or half-step)
• Individual level controls per voice