The Quasimidi Polymorph is a sample-based&DSP modelling desktop synthesizer module. It represented a significant departure from the company's dance-oriented heritage, offering a sophisticated synthesis engine that transcends genre boundaries. While maintaining real-time modulation controls and an analogue-style sequencer interface that appeals to electronic music producers, the Polymorph conceals a powerful and versatile synthesizer beneath its functional exterior.

Design & Build Quality

Presented as a desktop module with a slate-grey control surface and military steel chassis, the Polymorph eschews contemporary trends for colorful aesthetics in favor of a distinctly German functional approach. The unit features 42 positive dark blue switches that glow deep purple when selected, and 44 smooth-action knobs (though somewhat wobbly). A compact 2×16 character LCD screen, two larger ratcheted control knobs, and a conveniently top-mounted headphone jack complete the interface. Measuring 400mm wide, 225mm deep, and 98mm high, the unit weighs just 3 kilograms.

Synthesis Architecture

The Polymorph employs a hybrid synthesis approach combining DSP-generated waveforms with sampled oscillators, creating what Quasimidi terms "Analog Emulation Synthesis." The architecture supports either 8-voice polyphony with three oscillators per voice, or 16-voice polyphony when using only two oscillators. Voice allocation is dynamic across four multitimbral parts, with each part functioning as a complete virtual synthesizer.

Oscillator Section:

Oscillator 1 offers an impressive array of 128 DSP-generated waveforms covering sine, triangle, trapezoid, rectangular, sawtooth, and pulse waves with numerous transition stages. An additional 128 sync waveforms become available when the Sync button is engaged, though the sync oscillator itself operates with limited user control—it maintains 1:1 key-tracking and cannot be detuned. The oscillator benefits from its own pitch envelope with attack and decay parameters, which can also modulate pulse width. When sync is disabled, this envelope affects all three oscillators simultaneously.

Oscillators 2 and 3 utilize sampled waveforms including recognizable sounds like Mellotron, orchestral strings (possibly Roland RS202-derived), Moog-style bass, Kawai K5-like additive waves, and various synthesis staples. These 30 sampled waves span categories from SineWave and DeepMoog to Voices and Spectrm2. While characterful, the multi-sampling occasionally reveals noticeable keymapping boundaries. Each oscillator provides coarse and fine tuning controls, with a mixer determining their contribution to the final voice. Notably, OSC3 can be replaced with external audio via the two rear-panel inputs, allowing external signal processing through the Polymorph's filters and effects.

Filter Section:

The dual-filter architecture per voice comprises a switchable 12dB or 24dB/octave resonant low-pass filter and a 12dB/octave resonant high-pass filter, neither of which achieves true self-oscillation. The filters can operate in series (creating band-pass responses) or parallel (for notch filtering), with an option to couple their cutoff frequencies for simultaneous sweeping at constant intervals—a feature rare outside modular systems like the Crumar Spirit.

Beyond the front-panel controls, 25 menu pages unlock extensive filter capabilities including overdrive/distortion for aggressive timbres, velocity sensitivity, and key tracking from zero to 1:1 on the low-pass filter. Each filter has its own invertible ADSR envelope generator and dedicated LFO depth controls with both positive and negative polarities.

LFO Section:

Three LFOs per patch serve dedicated functions: LFO1 handles pulse width modulation (and sync oscillator frequency when in sync mode), LFO2 provides pitch modulation (VCO-FM), and LFO3 modulates filter cutoff and amplifier level. Each offers six waveforms—sine, sawtooth, reverse sawtooth, square, triangle, and random (for sample-and-hold effects). LFO rates can be set freely or synchronized to the internal sequencer across seven divisions (from 16 periods per bar to one period every four bars). LFO1 and LFO2 include menu-accessible delay parameters for delayed vibrato effects.

Envelope Generators:

Four independent ADSR envelope generators per voice control the low-pass filter, high-pass filter, VCA, and oscillator pitch (AR envelope). All modulation intensities are reversible, providing exceptional sound-shaping flexibility.

Effects Processing:

Perhaps the Polymorph's most distinctive feature is its effects architecture: each of the four multitimbral parts receives four dedicated insert effects, totaling 16 simultaneous effect processors. The first effect combines distortion with an additional 24dB/octave resonant low-pass filter. While the distortion exhibits a characteristically digital harshness (ideal for aggressive leads but less suitable for polyphonic material), the accompanying filter tames excessive high frequencies.

The second effect provides 2-band EQ with independent frequency (5-127) and gain (-64 to +63, ±12dB maximum) controls for low and high bands, likely employing shelving filter topologies.

Effects units FX1 and FX2 offer assignable modulated delays including chorus, flanging, and delay. FX1 provides seven monophonic effects while FX2 delivers six stereo-spread effects. Both share common parameters: effect level, delay time (ranging from 0.1ms to 870ms depending on effect type), feedback amount, feedback filter for high-frequency damping, and modulation speed/intensity via dedicated sine-wave oscillators. Selected delays can synchronize to sequencer note values (1/16, 1/8, or 1/4 notes). Notably absent are true reverb effects.

The Sequencer

The Polymorph's sequencer transcends simple step-sequencing, offering four independent monophonic sequences with up to 16 steps each. Eight front-panel knobs access steps in groups of 1-8 or 9-16, switchable in real-time during playback. Individual steps can be muted, and four programmable parameters per step—pitch plus three assignable "lines"—can control any of 69 destination parameters including filter cutoff, resonance, portamento, and numerous other synthesis parameters.

Each sequence supports forward, backward, note-forward, and random playback orders, with independent loop lengths per line enabling polymetric patterns. The four sequences can run at different clock rates and trigger each other for extended pattern creation. Eight sub-sequences within each main sequence provide different muting sets and transpositions, selectable via front-panel buttons or MIDI key numbers.

Additional buried parameters include groove amount, MIDI triggering/transposition options, and sophisticated voice allocation modes: Multi (standard multitimbral), Rotate (cycles through four patches on sequence 1), Stack (layers all four patches on sequence 1), and Unison (four instances of patch 1 for thick textures). LFOs and delay effects can synchronize to step rates, and real-time sound editing during sequence playback is fully supported. The system stores 50 dedicated sequencer memories, with an additional 256 sequencer setups available within the four setup banks (4×64).

MIDI Implementation

The Polymorph transmits all control movements via MIDI, enabling comprehensive automation when paired with external sequencers. This captures not only note data but every knob tweak and parameter change, preserving the spontaneity of live performances. The System menu provides master transposition, fine-tuning, MIDI channel assignments, synchronization, input/output filters, and SysEx capabilities. Three knob response characteristics prevent unpleasant parameter jumps during real-time adjustments.

Performance Controls

Seven performance parameters reside in the Control menu: velocity response curve, sustain on/off, pitch bend sensitivity, modulation wheel assignment and depth (±50% or ±100%), plus aftertouch assignment and depth. Both modulation wheel and aftertouch can target any of 32 destinations spanning oscillator parameters (waveform, level, detune, pitch EG, PWM), filter parameters (cutoff, resonance, drive, LFO rate/depth), effects parameters (level, feedback, rate, depth for both FX units, plus distortion controls), and pan. Aftertouch applied to OSC1 waveform in sync mode produces striking "tearing" effects and PPG-style wavetable sweeps.

Sound Character

The Polymorph delivers a unique sonic palette blending late-1970s analogue concepts with late-1980s digital synthesis and contemporary DSP technology. OSC1's DSP-generated waveforms can be aggressively unpleasant in the best possible way, while OSC2 and OSC3's sampled content adds unexpected smoothness and body. The synthesis engine excels at screeching excesses, convincing Mellotron emulations, aggressive bass, and thick pad sounds. Factory patches lean heavily on early 1970s electronica, 1980s electro-pop, and 1990s dance/trance, though the architecture supports far wider musical applications.

Technical Specifications

Synthesis & Voice Architecture

• Synthesis Type: Sample-based / DSP Modelling (Analog Emulation Synthesis)
• Polyphony: 8 voices (3 oscillators) or 16 voices (2 oscillators)
• Multitimbrality: 4-part with dynamic voice allocation

Voice Allocation Modes:

• Multi: Standard multitimbral operation
• Rotate: Cycles through 4 patches on sequence 1
• Stack: Layers all 4 patches on sequence 1
• Unison: 4 instances of patch 1 for thick sound

Oscillators

• Configuration: 3 independent oscillators per voice (8-voice mode) / 2 per voice (16-voice mode)
• OSC1 Waveforms: 256 total (128 standard + 128 sync)
  • Sine (×4), Triangle (×4), Trapezoid (×28), Rectangular (×8)
  • Reverse Sawtooth (×4), Sawtooth (×8), M Sawtooth (×8)
  • Pulse (×64), Sync (×128)
• OSC2/OSC3 Samples: 30 waveforms including:
  • SineWave, DeepMoog, DeepBass, Sequenz series (1-4)
  • BellWave, ResBass series (1-2), WetBass series (1-2)
  • Sawtooth series (1-3), FatWave series (1-3)
  • Synced series (1-2), Sync_Up
  • Orchestr, Strings, Mellotron, ChorWave, Voices
  • DigiWave, Spectrm series (1-2), Effect, NoiseOSC
• Oscillator Features:
  • Coarse and fine tuning per oscillator
  • Sync oscillator (1:1 key-tracking, fixed)
  • Pulse width modulation (PWM)
  • Wave morphing capability
  • Independent pitch envelope (Attack/Decay) for OSC1
  • External audio input can replace OSC3

Filters

• Primary Filters: 2 per voice
  • Low-pass: Switchable 12dB or 24dB/octave with resonance
  • High-pass: 12dB/octave with resonance
• Filter Modes: Series (band-pass) or Parallel (notch filter)
• Filter Features:
  • Filter coupling (simultaneous cutoff sweeping)
  • Overdrive/distortion capability
  • Key tracking (0 to 1:1 on low-pass filter)
  • Velocity sensitivity
  • Dedicated ADSR envelope per filter (invertible)
  • Individual LFO depth controls (positive/negative polarity)
• Note: Filters do not achieve true self-oscillation

LFOs

• Number: 3 per patch
  • LFO1: Pulse width modulation (PWM) + Sync oscillator frequency
  • LFO2: Pitch modulation (VCO-FM)
  • LFO3: Filter modulation + VCA modulation
• Waveforms: 6 types
  • Sine, Sawtooth, Reverse Sawtooth, Square, Triangle (Trl), Random
• LFO Parameters:
  • Rate (free-running or sequencer-synced)
  • Depth control
  • Delay (LFO1 and LFO2 only, menu-accessible)
• Sync Rates: 7 divisions (16 periods/bar to 1 period/4 bars)

Envelopes

• Number: 4 independent ADSR generators per voice
  • Pitch envelope (Attack/Decay only)
  • Low-pass filter envelope (ADSR)
  • High-pass filter envelope (ADSR)
  • VCA envelope (ADSR)
• Features: Reversible modulation intensity

Effects

• Total Processors: 16 (4 per multitimbral part)
• Effect 1 (Fixed): Distortion + 24dB/octave resonant low-pass filter
• Effect 2 (Fixed): 2-band EQ
  • Low and high band frequency control (5-127)
  • Low and high band gain control (-64 to +63, ±12dB max)
• FX1 (Assignable, Mono): 7 effect types
  • Flanger (0.1-13.6ms)
  • Space Flanger (0.2-27.2ms)
  • Chorus (0.4-54.4ms)
  • Super Chorus (0.9-108.7ms)
  • Short Delay (1.7-217.5ms, 1/16 note sync)
  • Delay (3.4-435.0ms, 1/8 note sync)
  • Long Delay (6.8-870ms, 1/4 note sync)
• FX2 (Assignable, Stereo): 6 effect types
  • Stereo Flanger (0.1-13.6ms)
  • Stereo Flanger (0.2-27.2ms)
  • Stereo Chorus (0.4-54.4ms)
  • Stereo Chorus (0.9-108.7ms)
  • Stereo Delay (1.7-217.5ms, 1/16 note sync)
  • Pan Delay (3.4-435.0ms, 1/8 note sync)
• Effect Parameters:
  • Level, Delay Time, Feedback Amount
  • Feedback Filter (6dB/octave high-frequency damping)
  • Modulation Speed, Modulation Intensity
• Note: No true reverb effects available

Sequencer

• Type: Analog-style step sequencer (DSP-based)
• Sequences: 4 independent monophonic sequences
• Steps: Up to 16 steps per sequence
• Programmable Lines: 4 per sequence (Pitch + 3 assignable controller lines)
• Assignable Parameters: 69 destinations per line
• Playback Modes: Forward, Note-Forward, Backward, Random
• Features:
  • Independent loop length per line (polymetric capability)
  • Step mute and step hold
  • Different clock rates per sequence
  • Sequence triggering/chaining
  • 8 sub-sequences per main sequence (muting/transposition)
  • Real-time transposition
  • Real-time sound editing during playback
  • Groove amount control
  • MIDI triggering and transposition

Memory

• Single Patches: 128 memories
• Sequencer Patterns: 50 dedicated memories
• Setup Memories: 4 banks × 64 = 256 total
  • Each setup contains 4 patches + sequencer data
  • Total accessible patches: 128 + (4 × 64) = 384 sound memories
  • Total sequencer memories: 50 + 256 = 306 memories

Control & Performance

• Velocity Response: Programmable curve
• Pitch Bend: Adjustable sensitivity
• Modulation Wheel: Assignable to 32 destinations, ±50% or ±100% depth
• Sustain: On/Off
• Knob Response: 3 selectable characteristics (jump prevention)
• 44 knobs
• 42 switches
• 2 ratcheted encoder knobs

Display

• 2×16 character LCD

Aftertouch

• Assignable to 32 destinations (32 total), ±50% or ±100% depth:
  
  • Oscillator: OSC1 Wave, OSC1 Level, OSC2 Detune, OSC2 Level, OSC3 Detune, OSC3 Level, Pitch EG Amount, PWM EG Amount, PWM Rate, PWM Depth, FM Rate, FM Depth
  • Filter: LPF Cutoff, LPF Resonance, HPF Cutoff, HPF Resonance, Filter Drive, LFO3 Rate, LFO3 Depth
  • Effects: FX1 Level/Feedback/Rate/Depth, FX2 Level/Feedback/Rate/Depth, Distortion Gain, Distortion Filter Cutoff, Distortion Filter Resonance
  • Output: Pan

MIDI

• Ports: In, Out, Thru
• MIDI Channels: 4 parts independently assignable
• MIDI Features:
  • Complete real-time control transmission
  • Sequencer synchronization (master/slave)
  • Input and output filtering
  • SysEx support
  • Master transposition and fine-tuning
  • Local On/Off (enables internal sequencer MIDI transmission)
  • Records all knob movements and parameter changes

Audio

• Outputs: 4 individual outputs (assignable per part)
• Inputs: 2 audio inputs (can replace OSC3 for external signal processing)
• Headphone Output: Front panel mounted (3.5mm jack)

Physical Specifications

• Dimensions: 400mm (W) × 225mm (D) × 98mm (H)
• Weight: 3 kg
• Construction: Steel chassis with slate-grey control surface