Sequential Fourm

4 Voice Polyphonic Analog Synthesizer Keyboard

• 4-voice Prophet-5 architecture with 100% analog signal path
• 37-key slim Tactive™ keyboard with polyphonic aftertouch
• Pro-One-style modulation with top-panel matrix
• 64-step polyphonic sequencer that can also be used as a modulation source
• Advanced arpeggiator with creative modes and synchronization
• Rugged steel construction with knob-per-function layout

Fourm: Sequential's new expressive standard

Fourm is a compact 4-voice polyphonic analog synthesizer that combines Sequential's sonic heritage with a new expressive frontier: the Tactive™ keyboard with polyphonic aftertouch. Based on the Prophet-5 architecture, it offers tone, warmth and dynamic response that have defined generations of synths, now in a modern, versatile format.

Two Prophet oscillators per voice, classic filters, legendary sound

Each voice integrates two oscillators with simultaneous waveforms, Prophet-style sync, variable PWM, white, pink and violet noise. The 4-pole filter with bass compensation maintains depth and definition even with pushed resonance, and is capable of self-oscillation.

Total control: creative modulations, sequencing and arpeggios

Pro-One modulations and polyphonic aftertouch

Top-panel matrix allows instant routing between sources such as envelopes, LFOs, oscillators. Polyphonic aftertouch allows per-note articulations on cutoff, amplitude, oscillator frequencies, LFOs, and more.

Modular sequencer and advanced arpeggiator

The 64-step sequencer supports Acid-style glides, chords, slurs, rests and can act as a modulation source. Arpeggiator includes 6 modes, rilatch, repeat and detailed time division.

Compact, solid and professional design

Steel chassis, custom-designed keyboard and dedicated knob layout make Fourm a stage- and studio-ready instrument. Includes MIDI DIN, USB-C, pedal inputs, headphone output and universal power supply included.

Specifications:

• 4 voices with 2 Prophet-5 oscillators per voice
• Simultaneously selectable waveforms, sync, PWM
• Prophet 4-pole filter with bass compensation
• Noise white, pink, violet
• 2 ADSR envelopes (filter and amplitude)
• Global LFO with 7 waveforms
• Polyphonic aftertouch with 6 simultaneous destinations
• 64-step sequencer, arpeggiator with 6 modes
• Tactive™ keyboard with 37 slim keys
• Outputs: audio, headphones, MIDI DIN, USB-C, pedal
• Steel chassis, spring-loaded pitch wheel
• Dimensions: 56.2 × 25.1 × 7.0 cm - Weight: 3.97 kg