Sequential Fourm Polyphonic Analogue Synthesizer

4-voice analog synthesizer with Polyphonic Aftertouch

Legendary Analog Sound, Reimagined

Fourm delivers four genuine voices of Sequential analog sound, built on the legendary Prophet-5 voice architecture - right down to its envelope response curves. With dual oscillators offering simultaneous wave selection and a classic 4-pole low-pass filter, now enhanced with bass compensation, Fourm captures the warmth and punch that shaped a generation - and takes it to the next level.

A New Fourm of Expression

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 - completely transforming the experience of playing a modern analog polysynth.

Modulation You Can Touch

Inspired by the Pro~One, Fourm’s top-panel modulation matrix puts deep sound design at your fingertips—no menu diving required. Route sources and destinations with a button press, visualize connections with color-coded indicators, and build complex modulation paths in seconds. It’s fast, intuitive, and designed to keep you in the creative flow.

Fourm's Features

• 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 

SYNTHESIS

• All oscillators have simultaneously selectable waveforms – LFO too
  
• Oscillator B supports low frequency modes
  
• Classic Prophet-style Sync
  
• 4-Pole resonant lowpass filter 
  
• Feedback with aggressive drive circuit
  
• 2 ADSR envelopes 
  
• Sequencer supports glide per step 

IN/OUT

• Main output mono (1/4” jack) 
  
• Headphone output mono (1/4” TRS phone jack) 
  
• MIDI in, out, and thru ports 
  
• USB for bidirectional MIDI communication 
  
• Footswitch/expression pedal input 

POWER

• Separate power switch
  
• 12V DC 1.2A power supply, center-positive (included)
  
• Can be plugged into an AC outlet capable of supplying from 100 V to 240 V at 50 Hz/60 Hz.
  
• 14 Watts maximum power consumption.

PHYSICAL SPECS

• 22.13" L x 9.88" W x 2.75" H (56.2 cm x 25.1 cm x 7.0 cm) 
  
• Weight: 8.76 lbs. (3.97 kg) 
  
• Anti-theft slot