MIDI ControllerOverreview

Arturia KeyStep 37

The pocket-sized hybrid sequencer reviewers hand modular and synth players by default — loved for its CV connectivity and aftertouch, argued over for its one-track sequencer and Arturia's key QC.

9 sourcesUpdated
$169Typical US price

Score aggregates reviewer opinions across topics.

Arturia KeyStep 37

The short version

What to know.

A compact 37-key hybrid controller and step sequencer, around $170, built for driving hardware synths, modular and a DAW from one keyboard. Reviewers broadly agree on two strengths: unusually complete connectivity for the size — USB, 5-pin MIDI In/Out, CV Pitch/Gate/Mod and analog clock, plus a sustain input — and a slim keybed with velocity and aftertouch, the aftertouch being a genuine rarity at the price. Its creative feature set (an 8-mode arpeggiator with generative Walk/Pattern modes, a 12-voicing Chord mode with Strum, and Scale mode) is widely called fun and inspiring, and the workflow is fast and menu-free. Opinion splits on the sequencer: some love that it's immediate and simple, others find the single, linear track too limiting — you sequence one part at a time and can't freely play alongside a running sequence (the KeyStep Pro adds four tracks). Build is generally called solid (metal baseplate), but Arturia's key/QC reputation is a real caveat — a minority of owners report uneven or dead keys, or a warped chassis, out of the box. The software bundle is minimal (Ableton Live Lite only), and 37 slim keys can feel short for two-handed playing. The original is now superseded by the 2025 Mk2 (USB-C, OLED screen, four CV outputs).

About this product

The original KeyStep 37 (2020): 37 slim (Slimkey) keys with velocity and aftertouch, RGB LED key indicators, a single-track 64-step / 8-note-polyphonic sequencer, an 8-mode arpeggiator with Walk and Pattern generative modes, Chord mode (12 voicings) with a guitar-like Strum, Scale mode, four assignable knobs (16 MIDI CC across four banks) with a small screen, and hybrid connectivity — USB Type-B, 5-pin MIDI In/Out, CV Pitch/Gate/Mod, 3.5mm analog clock I/O and a sustain input. It sits between the 32-key KeyStep and the four-track KeyStep Pro. NOT the 2025 KeyStep 37 mk2 (USB-C, OLED screen, four assignable CV outputs, Mutate/Spice/Dice tools) and not the 32-key KeyStep.

Arturia's KeyStep 37 is the middle child of the French company's KeyStep line — sitting above the 32-key KeyStep and below the four-track KeyStep Pro. It's a 37-slim-key controller that's also a step sequencer, arpeggiator and CV/MIDI hub, with velocity-sensitive keys, aftertouch, RGB key lights, a supercharged Chord mode with a guitar-like Strum, Scale mode, and — the part reviewers keep coming back to — full hybrid connectivity (USB, 5-pin MIDI, CV/Gate and analog clock) in a compact slab.

Since 2020 it's been a fixture of hybrid hardware desks, widely described as an inspiring, menu-free idea generator rather than a DAW mixing surface. Where opinion genuinely splits is its sequencer — elegantly simple to some, a single linear track that's too limiting to others — and Arturia's key and QC reputation follows it. Note the original has since been succeeded by the 2025 KeyStep 37 mk2, which changes real specifics.

A good fit for

  • Players building a hybrid rig who want one keyboard to sequence and play hardware synths, modular (CV) and a DAW
  • Anyone who specifically wants aftertouch in a compact, affordable controller
  • Musicians who like generating ideas fast with arps, chords, strum and scales, with minimal menu-diving
  • Desktop or portable setups where a full standalone sequencer that runs without a computer matters

Think twice if

  • You need to sequence several synths or drum parts at once — the single track is limiting; look at the KeyStep Pro, a groovebox or a DAW
  • You want a deep DAW controller with auto-mapped transport and mixer control — a KeyLab or Launchkey is that, this isn't
  • You play a lot of two-handed parts — 37 slim keys can feel short, and there's no full-size or weighted-key option
  • You want a guaranteed-perfect unit out of the box — Arturia's key QC varies, so buy where returns are easy and check yours

The reviewer consensus

Agreement &
disagreement.

1 / 8topics divide opinion
connectivitykeybedintegrationportabilitybuildvaluecontrolssoftware
1 Strong agreement5 Mostly agree1 Divided opinions1 Limited evidence

Common ground4

  • Unusually complete connectivity for the size — USB, 5-pin MIDI In/Out, CV Pitch/Gate/Mod and analog clock I/O, plus a sustain input — so it drives modular, hardware synths and a DAW from one keyboard
  • A slim keybed with velocity and aftertouch — aftertouch is a genuine rarity in this class and a top reason players pick it
  • A creative, menu-free feature set: an 8-mode arpeggiator with generative Walk/Pattern modes, a 12-voicing Chord mode with a guitar-like Strum, and Scale mode

Points of contention3

  • The sequencer: elegantly simple and fun to some; a single, linear track that's too limiting (one part at a time, no free-play over a running sequence) to others — the four-track KeyStep Pro is the scale-up answer
  • Build and reliability: a solid-feeling metal-baseplate unit for most, but Arturia's key QC is a lottery for a minority — uneven or dead keys, gritty action, or a warped chassis out of the box
  • 37 slim keys: perfectly portable and enough for sketching to some; too few keys and too small for comfortable two-handed playing to others

A closer look.

8 topics · 1 divided
Left: criticalRight: positiveTighter lines: more agreementDashed: limited evidence

Keybed

PositiveMostly agree
Reviewer sentiment4 supporting sources
CriticalNeutralPositive

Band: opinion spread · Dot: weighted average

A quiet strength, and the aftertouch is the headline. The 37 slim (Slimkey) keys are velocity-sensitive with aftertouch — a genuine rarity in an affordable compact controller, and the single most-cited reason players choose it over rivals. The feel is well-liked (even one reviewer who prefers a competitor's keys calls the KeyStep's 'very good'), though the keys are small and 37 of them can feel short for two-handed chord work. Individual-unit quality varies — that's covered under build.

“a solid keybed with aftertouch packed in an affordable unit”

Synth Anatomy

“Aftertouch is something I really want, but which isn't available in other controllers (that I can find).”

u/The_Diamond_Sky · r/synthesizers

“The sequencer and arp are great, and even though the keys are tiny, I like the way they feel.”

u/denim_skirt · r/synthesizers

Measured

Spec: 37 slim (Slimkey) keys spanning three octaves, with velocity and aftertouch and real-time RGB LED key indicators; octave up/down transpose. No full-size or weighted-key option.

Link to this topic

The hardware

Specifications.

Checked

Playing surface

Keys
37 slim-size
Knobs
4
Pitch / mod
Touch strips

Workflow

Standalone
Yes
Sequencer
Yes
Arpeggiator
Yes

Connection

MIDI
DIN in, DIN out
Pedal inputs
Sustain
Power
USB bus power, Power adapter

Physical

Weight
1,600 g
Dimensions
550 × 147 × 35 mm

Manufacturer-published figures, not measurements · from arturia.com (archived), dl.arturia.net.

Follow the evidence

Sources 9

1–6 of 9 sources

Read with context

Limitations & method.

As of

What to keep in mind 5

  1. A read of where opinion lands as of July 2026 — the compact-controller field keeps moving.

  2. The original KeyStep 37 has been succeeded by the 2025 KeyStep 37 mk2, which changes real things (USB-C, an OLED screen, four assignable CV outputs and generative Mutate tools) — so check exactly which version a listing is, and expect the original mostly on the used market now.