Fourm

Classic Analog Sound
Delivers warm, punchy synthesis with a rich and organic character inspired by classic Sequential instruments.

Polyphonic Aftertouch
Lets you add expression to individual notes by applying extra pressure to each key while playing.

Dual Analog Oscillators
Provides flexible waveform combinations for creating everything from deep basses and leads to evolving pads and textures.

Vintage-Style Filtering
Shapes sounds with a distinctive analog filter character that can move from smooth and warm to bold and resonant.

Flexible Sound Shaping
Dedicated filter and amplifier envelopes make it easy to control how brightness and volume evolve over time.

Powerful Modulation
Routes multiple modulation sources to key sound parameters for expressive movement, animation, and creative sound design.

Versatile LFO
Adds vibrato, tremolo, filter movement, random modulation, and other evolving effects.

Vintage Character Control
Introduces subtle voice-to-voice variations for a more organic, aged analog feel.

Expressive Performance Controls
Pitch, modulation, velocity, aftertouch, and pedal control make sounds more responsive during live playing.

Unison Mode
Stacks voices together for thicker, more powerful basses, leads, and other monophonic sounds.

Chord Memory
Stores a chord and lets you trigger or transpose the entire chord from a single key.

Glide
Creates smooth pitch transitions between notes for expressive leads, basses, and classic synth effects.

Built-In Arpeggiator
Automatically turns held notes into rhythmic patterns with several playback styles.

Note and Modulation Sequencing
Creates repeating musical phrases or moving parameter patterns directly from the instrument.

Hands-On Editing
Places the main sound-shaping controls on the front panel for quick and intuitive programming.

Live Panel Mode
Lets the sound follow the current knob and button positions for immediate experimentation without relying on a preset.

Preset Management
Makes it easy to browse, edit, name, organize, and save custom sounds.

Alternative Tunings
Supports different tuning systems for experimental, microtonal, and non-standard musical applications.

Computer and MIDI Integration
Connects easily with computers, sequencers, and other MIDI equipment for studio and live setups.

Pedal Control
Supports sustain or expression pedals for hands-free performance control over selected sound parameters.

General Specifications
Device Type: Compact 4-voice analog polyphonic synthesizer
Voice Architecture: 4 voices
Synthesis Type: Analog subtractive
Program Memory: 512 program locations
User Memory: 256 writable programs
Factory Memory: 256 permanent programs
Alternative Tunings: Equal temperament plus 64 alternative tunings
Imported Tunings: SysEx supported

Keyboard and Performance
Keybed: Tactive slim-key keybed
Velocity Sensitivity: Supported
Aftertouch: Polyphonic, monophonic, or off
Aftertouch Curves: Medium, Hard 1, Hard 2, Soft 1, Soft 2
Velocity Curves: Medium, Hard+, Hard, Soft+, Soft
Pitch Wheel: Spring-loaded
Pitch Bend Range: 0–12 semitones
Modulation Wheel: Assignable modulation control
Keyboard Transpose: Octave up/down
Hold: Up to 4 notes
Chord Memory: Supported
Unison Voices: 1–4
Unison Detune: 0–127
Key Priority: Low, High, Last
Glide Modes: Fixed Rate, Fixed Rate A, Fixed Time, Fixed Time A

Oscillators
Oscillators per Voice: 2 analog voltage-controlled oscillators
Oscillator A Waveforms: Sawtooth, pulse
Oscillator B Waveforms: Triangle, sawtooth, pulse
Simultaneous Waveforms: Supported
Pulse Width: Continuously variable
Pulse Width Range: -63–64
Oscillator Fine Tune Range: ±7 semitones
Oscillator Octave Range: 5 octaves
Oscillator B Low-Frequency Modes: LO1, LO2
Oscillator Sync: Hard sync

Mixer
Oscillator A Level: Adjustable
Oscillator B Level: Adjustable
Feedback: Post-filter feedback
Feedback Range: 0–127
Feedback Saturation: Soft-clipping diode circuit
Noise Types: White, pink, violet
Noise Level Range: 0–127

Filter
Filter Type: Analog low-pass
Cutoff: Adjustable
Resonance: Adjustable to self-oscillation
Keyboard Tracking: Off, Quarter, Half, Full
Filter Envelope Amount: Bipolar

Envelopes
Envelope Generators: 2
Envelope Type: 4-stage ADSR
Filter Envelope: Attack, Decay, Sustain, Release
Amplifier Envelope: Attack, Decay, Sustain, Release
Filter Envelope Velocity Amount: 0–127
Amplifier Envelope Velocity Amount: 0–127
Envelope Retrigger: Off, On

Low-Frequency Oscillator
LFO Frequency Range: 0.021–556 Hz
Waveforms: Triangle, sawtooth, reverse sawtooth, square, sample-and-hold
Additional LFO Sources: Random, pink noise, white noise, violet noise, DC
Simultaneous LFO Waveforms: Supported
Clock Sync: Internal or external
Sync Divisions: 32 steps to 1/16 step

Modulation
Primary Modulation Sources: Filter Envelope, Oscillator B, LFO
Primary Modulation Destinations: Oscillator A Frequency, Oscillator B Frequency, Oscillator A Pulse Width, Oscillator B Pulse Width, Filter Cutoff, Amplifier, LFO Frequency, LFO Amount
Modulation Polarity: Bipolar
Modulation Buses: Direct, Mod Wheel
Aftertouch Destinations: Oscillator A Frequency, Oscillator B Frequency, Filter Cutoff, Amplifier, LFO Frequency, LFO Amount

Arpeggiator and Sequencer
Arpeggiator Modes: Up, Down, Up+Down 1, Up+Down 2, Random, Assign
Arpeggiator Octave Range: 1–3 octaves
Arpeggiator Repeat: Off, 1, 2, 3
Arpeggiator Relatch: Off, On
Beat Sync: Off, On
Sequencer Types: Note, modulation
Sequencer Length: Up to 64 steps
Sequence Step Types: Note, chord, rest, tie, glide
Sequence Playback Modes: Retrig, Continue, One Shot, Step
Modulation Sequence Destinations: Oscillator A Frequency, Oscillator B Frequency, Filter Cutoff, Mod 1 Amount, Mod 2 Amount, Mod 3 Amount, LFO Frequency, Pulse Width A, Pulse Width B, Pulse Width All, Feedback
Clock Tempo Range: 30–250 BPM
Clock Divisions: 1/2, 1/4, 1/8, dotted 1/8, swung 1/8, 1/8 triplet, 1/16, swung 1/16, 1/16 triplet, 1/32, 1/64

MIDI and USB
MIDI DIN: In, Out, Thru
MIDI Channels: 1–16, All
USB Connector: USB-C
USB Function: Bidirectional MIDI
USB Compliance: Class compliant
Computer Compatibility: macOS, Windows
MIDI Parameter Transmission: Off, CC, NRPN
MIDI Parameter Reception: Off, CC, NRPN
MIDI Clock Modes: Off, Out, In, In/Thru
Clock Input: MIDI, USB
Clock Output: None, MIDI, USB, All
System Exclusive: Supported
Program Change Send/Receive: Supported
Arpeggiator MIDI Note Output: Supported

Audio Connections
Main Audio Output: 1/4-inch unbalanced
Headphone Output: 1/4-inch stereo
Headphone Level Control: Main Volume control

Pedal Connections
Pedal Input: Shared footswitch/expression pedal jack
Expression Pedal Connector: 1/4-inch TRS
Footswitch Types: Momentary normally open or normally closed
Footswitch Functions: Sustain, Arp Hold, Arp Hold Momentary, Sequence Start/Stop, Trigger, Gate, Trigger + Gate
Expression Pedal Functions: Filter Full, Filter Half, Filter Envelope Mod Amount, Oscillator B Mod Amount, LFO Mod Amount, Volume
Footswitch Polarity: Normal, Reverse

Power
DC Input: 12.0 V
Current Requirement: 1.25 A
Power Supply Input: 100–240 V AC
Power Supply Frequency: 50–60 Hz
Power Supply Rating: 15 W

Physical and Security
Chassis: Steel
Security Slot: Computer-style security cable lock slot