SEQUENTIAL FOURM | 4-voice Analog Keyboard Synthesizer

Fourm

Compact 4-Voice Analog Poly Synthesizer

The Sequential Fourm is a compact, 4-voice analog synthesizer that's built on the legendary Prophet-5 voice architecture including the original envelope response curves and the classic Prophet 4-pole filter with enhanced bass compensation. The dual-oscillator sound engine offers simultaneous wave selection, unison, and the classic prophet-style sync.

Fourm’s 37-note slim-key keyboard features polyphonic aftertouch, unlocking expressive techniques like guitar-style note bends, solo voice swells, and other nuanced articulations. The top panel is inspired by the Pro-One with its deep modulation matrix easily accessible at your finger tips. Route sources and destinations with a button press, visualize connections with color-coded indicators, and build complex modulation paths in seconds. The Fourm includes a 12 VDC power supply. 

• 37-note slim-key keyboard with polyphonic aftertouch
• Warm and organic, 100% analog signal path
• Intuitive, welcoming knob-per-function layout
• Pro-One style top-panel modulation matrix
• Prophet-lineage resonant filter with bass compensation
• Arpeggiator with sequencer mode
• 128 world-class presets
• Pro-quality, all-steel chassis
• All oscillators have simultaneously selectable waveforms (including the LFO)
• Oscillator B supports low-frequency modes
• Classic Prophet-style sync
• 4-pole resonant low-pass filter
• Feedback with aggressive drive circuit
• 2 ADSR envelopes
• Sequencer supports glide per step

Specifications

• Sound Generation
  • Analog
• Keyboard
  • 37 Slim Keys with Synth Action
• Touch Sensitivity
  •  Yes
• Aftertouch
  • Polyphonic Aftertouch (Destination Assignable)
• Expression Controls
  • 1x Pitch Bend
  • 1x Modulation
• Display
  • Monochrome LCD
• Sounds 
  • 128x Factory Sound Preset
• Maximum Polyphony
  • 4 Voice
• Multitimbrality
  • 1-Part
• Performance Functions
  • Arpeggiator, Octave Shift, Sequencer
• Oscillators
  • 2x Variable (Sawtooth, Sine, Square)
• Mixer
  • Oscillator, Oscillator 2, White Noise (Level)
• Amplifiers
  • 1x VCA
• Envelopes
  • 2x Filter/VCA/Assignable Envelope Generator: Delay, Attack, Decay, Sustain, Release
• Filter
  • Characteristic: Analog CEM 3320 Chip
  • Type: Low-Pass
  • Slope: 4-Pole/24 dB (LPF)
  • Controls: Cutoff, Resonance, Envelope Amount
• LFOs
  • Number of LFOs: 1x Global
  • Waveforms: Sawtooth Up, Sawtooth Down, Square, Triangle, Random, Sample & Hold
  • Controls/Modes: Clock Sync
  • Destinations: Oscillator 1 Frequency, Oscillator 2 Frequency, Oscillator 1 and 2 Pulse Width, Low-Pass Filter Cutoff, VCA, VCF, VCO, Filter Cutoff, Amp
• Modulation Matrix
  • 11-Slot per Patch (3 Sources / 8 Destinations)
• Aftertouch Destinations
  • Amplifier Envelope Amount, Filter Cutoff Frequency, LFO Amount, Low-Pass Filter Cutoff, Oscillator 1 Frequency, Oscillator 2 Frequency, VCA
• Glide/Portamento
  • Yes
• Arpeggiator
  • Yes
• Audio I/O
  • 1x 1/4" TRS Main Output
  • 1x 1/4" TRS Unbalanced Stereo Headphone Output
• Pedal Support 
  • 1x 1/4" Expression/Footswitch
• MIDI I/O
  • 1x DIN 5-Pin Input
  • 1x DIN 5-Pin Output
  • 1x DIN 5-Pin Thru
• USB I/O
  • 1x USB-C (Host Connection, MIDI)
• Power Requirements
  • AC/DC Power Adapter (Included)
• AC Input Power
  • 100 to 240 VAC, 50 / 60 Hz AC/DC 
• Power Adapter
  • 12 VDC at 1.2 A, Center-Positive (Included) Power Consumption 14 W
• Color
  • Black 
• Dimensions
  • 22.1 x 9.9 x 2.8" / 56.1 x 25.1 x 7.1 cm
• Weight
  • 8.8 lb / 4 kg

In The Box

• Sequential Fourm Compact 4-Voice Analog Poly Synthesizer
• Power Adapter
• Limited 1-Year Manufacturer Warranty