Fourth State Electronics Mk I MIDI controller — top view showing 16-pad grid, five knobs, and touchscreen

Mk I

A standalone MIDI controller designed to run your whole live setup. Three independent outs, per-port processing (routing, tuning, chord gen, filter, arpeggiator, clock), and a touchscreen for live edits. Keep the keyboard you have, no laptop, nothing to install. Small enough to fit on top of it.

Discover

Control three MIDI devices from one keyboard.

Every port carries the full processing chain — zone the keyboard by note range, send program changes, assign knob CCs, retune, shape velocity, latch notes, filter unwanted MIDI signals, expand notes into chords, arpeggiate, and send tempo-synced clock. Sync the whole rig to incoming clock on MIDI IN. Configure per port, per preset.

Signal flow: master keyboard into the FSE Mk I, routed out to a synthesizer, a drum machine, and a MIDI effects unit. Every port carries the full processing chain (zone, transpose, program, CC assignment, velocity, MIDI filter, tuning, chord generator, arpeggiator, clock).
Fourth State Mk I top view with numbered callouts: 1 On-device touchscreen editor, 2 Sixteen backlit buttons, 3 Five programmable knobs.

Three independent MIDI outs

Ports A, B, and C — each with its own mode, note zone, transpose, program change, tuning, velocity curve, arpeggiator, MIDI filter, and chord generator. Route any part of your keyboard to any port, all independently.

Microtonal tunings per port

12-EDO (standard), 19-EDO, 24-EDO quartertones, 31-EDO, 5-limit Just Intonation, Pythagorean, Slendro, Pelog. Each output can run a different tuning at the same time.

Velocity

Shape dynamics with curves, gain, and offset.

Arpeggiator

Arpeggiate held chords with rate, gate, and latch.

MIDI filter

Block specific CCs, program change, pitch bend, or aftertouch.

Chord generator

Expand single notes into 12 chord voicings.

MIDI clock — master or slave

Generate a rock-solid 24 PPQ clock and route it to any combination of the three outs, or slave the whole rig to external clock on MIDI IN. Tap-tempo from any button. Drum machines, delay pedals, and the onboard arpeggiator all lock to the same beat.

Anodized aluminum enclosure

Anodized aluminum, built for the road. 5.9 × 4.5 × 2.3 inches. Small enough to sit on any keyboard, sturdy enough for a lifetime of gigs.

Small.
Designed to fit your setup.

Fourth State Mk I — top view with physical dimensions (5.9 × 4.5 in)
Fourth State Mk I — back panel with physical dimensions (2.3 in tall). MIDI OUT A/B/C, MIDI IN, USB-C 5V power, and power switch.

Specifications

MIDI outputs
3 × 5-pin DIN (A, B, C)
MIDI input
1 × 5-pin DIN, optoisolated, forwarded to all outputs
Pads
16 RGB-lit programmable pads
Knobs
5 analog potentiometers with pickup mode
Display
1.9" 320×172 touchscreen
Memory
microSD card, 4 GB
Banks
16
Presets per bank
16
Total presets
256
Onboard features
Velocity curves · Per-port arpeggiator · MIDI filter · Chord generator · Latch · MIDI clock
Power
USB-C, 5 V DC
Enclosure
Anodized aluminum
Dimensions
5.9 × 4.5 × 2.3 in (150 × 114 × 58 mm)
Weight
5 lb

Order

Handbuilt to order.
Limited first run.

Each Mk I is assembled, flashed, and bench-tested by hand before it leaves. Handbuilt to order — ships in 1–3 weeks