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.

FEATURING

•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

Free 3-Year Warranty

In addition to the standard included manufacturer warranty, virtually all new products carry our exclusive, industry-leading, absolutely free Sound Pure 3-Year Warranty, which includes parts and labor. It's our way of adding real value to the personal touch our small, dedicated team brings to every purchase.

Coverage exclusions live in Terms & Conditions, Section 27. Read the warranty →