Sequential FOURM - 4-Voice Analog Synth with Polyphonic Aftertouch

The Sequential FOURM is a compact, performance-focused analog polysynth that brings expressive playing and deep sound design to the forefront. Built around a 37-note slim-key keyboard with native polyphonic aftertouch and a knob-per-function layout, FOURM offers an immediate, tactile workflow - ideal for studio, stage, and sound design work.

Inspired by classic Sequential designs, FOURM combines a Pro-One style top-panel modulation matrix with two oscillators per voice, a Prophet-lineage 4-pole resonant lowpass filter, and flexible sequencing/arp capabilities to create everything from tight basses and fat leads to evolving ambient textures.

Features

• 37-note slim-key Tactive keyboard with polyphonic aftertouch
• 100% analog signal path for warm, organic sound
• Pro-One style top-panel modulation matrix with color-coded routing LEDs
• Intuitive knob-per-function front panel; no menu diving
• Prophet-lineage resonant filter with bass compensation and aggressive feedback drive
• Arpeggiator with sequencer mode (sequencer supports glide per step)
• 128 factory presets and deep programming capability
• Pro-quality, all-steel chassis built for gigging and studio use

Specifications

• Voices: 4-voice analog polyphony
• Oscillators: 2 VCOs per voice (simultaneously selectable waveforms; LFO also offers selectable waveforms)
• Filter: 4-pole resonant lowpass (Prophet-style) with feedback/drive
• Envelopes: 2 × ADSR
• Modulation: Top-panel matrix (source to destination routing), LFO, aftertouch, envelopes
• Performance: Arpeggiator / 64-step sequencer mode, glide per step, multiple modulation sources
• Keys: 37 slim keys with polyphonic aftertouch
• Connectivity: Main mono output (1/4"), headphone (1/4" TRS), MIDI In/Out/Thru, USB-C (bidirectional MIDI), footswitch/exp pedal input
• Power: Separate power switch; 12V DC 1.2A center-positive supply included; 100–240V AC compatibility via supplied PSU; max 14W consumption
• Physical: 13" L × 9.88" W × 2.75" H (56.2 × 25.1 × 7.0 cm); Weight ≈ 3.97 kg (8.76 lbs); anti-theft slot

Compact, expressive, and built to perform - FOURM brings rare polyphonic aftertouch and an immediate modulation workflow to an accessible, stage-ready instrument.