Sequential Fourm – compact analog synthesizer for a new generation Sequential Fourm is a 4-voice, fully analog synthesizer built on the legacy of the legendary Prophet-5. It blends classic Sequential sound with modern features such as the Tactive™ keybed with polyphonic aftertouch, a hands-on Pro-One-inspired modulation matrix, and an intuitive knob-per-function layout. Designed for expressive playability, Fourm is equally at home in the studio and on stage.

Main Features 4 true analog voices Prophet-5 heritage architecture with classic envelope response 2 analog oscillators per voice with simultaneous waveform selection Classic 4-pole low-pass filter with bass compensation Tactive™ 37-key slim keybed with polyphonic aftertouch Hands-on modulation matrix inspired by the Sequential Pro-One Built-in arpeggiator with 6 modes + 64-step polyphonic sequencer Durable all-steel chassis – compact and portable Oscillators and Synthesis Two Prophet-lineage analog oscillators per voice Simultaneous waveform selection Oscillator B can function in low-frequency mode (as LFO) Prophet-style oscillator sync Pulse width modulation (PWM) per oscillator Noise sources: white, pink, violet Filter and Sound Character Classic 4-pole resonant low-pass filter (Prophet-5 Rev 1 & 2) Resonance can be driven to self-oscillation Bass compensation ensures strong low end at high resonance Keyboard tracking options: 1/4, 1/2, full Feedback/drive circuit for added edge and aggression Envelopes and Modulation Two ADSR envelopes: one for filter, one for amplitude Velocity modulation of envelope amounts for dynamic expression 1 global LFO with 7 waveforms: Sine Sawtooth Reverse sawtooth Square Sample & Hold Noise DC Up to 4 LFO shapes selectable simultaneously LFO sync to tempo at multiple subdivisions Pro-One Style Modulation Matrix Two modulation buses with multiple sources and destinations Panel sources: Filter envelope Oscillator B LFO Panel destinations: Oscillator A & B frequency Pulse width A & B Filter cutoff Amplitude LFO frequency and amount Polyphonic aftertouch with up to 6 destinations simultaneously Arpeggiator and Sequencer Arpeggiator with 6 modes Functions include relatching, repeats, step values Range up to 3 octaves Polyphonic step sequencer with up to 64 steps, featuring: Chords Rests Ties Acid-style per-step glide Sequencer can also function as a modulation source Voice Modes and Expression Unison mode with configurable number of voices Chord Memory – store and recall chord voicings Vintage setting introduces subtle per-voice variations for organic feel Polyphonic portamento (glide) Tactive™ Keybed 37 slim keys designed for expressive play Full support for polyphonic aftertouch Engineered specifically for the Fourm’s analog engine Enables individual note articulations and nuanced control Construction and Interface Professional-grade all-steel chassis Compact dimensions: 56.2 × 25.1 × 7.0 cm Weight: 3.97 kg Knob-per-function interface for immediate access Spring-loaded pitch wheel with configurable range (±1 to ±12 semitones) Connectivity Main mono output (¼″ jack) Headphone output (¼″ TRS) MIDI In, Out, Thru USB-C for bidirectional MIDI communication Footswitch/expression input (supports trigger/gate) Power: 12 V DC 1.2 A (supply included) Why Choose Fourm?

True analog signal path with Prophet heritage Rare polyphonic aftertouch capability Immediate hands-on control – no menu diving Portable yet rugged for stage and studio Rich modulation and sequencing options Conclusion The Sequential Fourm is a modern analog polysynth that combines the soul of classic instruments with cutting-edge expressive tools. Compact, powerful, and intuitive, it’s the perfect choice for musicians seeking direct connection to sound without compromise.