MIDI implementation

Every control of Arturia KeyStep 37 and the message it sends

Generated from the profile file, so it is the same table the on-screen controller plays. Channels are 1–16; numbers are real MIDI numbers.

MIDI implementation of Arturia KeyStep 37
Control	Type	Message	Ch	Number	Signal	LED feedback	Verified
Pitch `pitch`	touch strip	Pitch bend · springs to centre	1	0–16383 · centre 8192	`midi/keystep37/pitch`	—	yes
Mod `mod`	touch strip	CC	1	1	`midi/keystep37/mod`	—	yes
Sustain `sustain`	button	CC · momentary	1	64	`midi/keystep37/sustain`	—	yes
1 `k1`	knob	CC	1	74	`midi/keystep37/k1`	—	unverified
2 `k2`	knob	CC	1	71	`midi/keystep37/k2`	—	unverified
3 `k3`	knob	CC	1	76	`midi/keystep37/k3`	—	unverified
4 `k4`	knob	CC	1	77	`midi/keystep37/k4`	—	unverified
Keys `keys`	keys	Note · velocity	1	48–84 (C3–C6)	`midi/keystep37/keys/on · midi/keystep37/keys/off · midi/keystep37/n48…n84`	—	unverified

LED feedback is not modeled for this one yet, so OAV does not light its LEDs. Every control still plays and sends its message.

Sources

manufacturer KeyStep Manual v1.1.2 (Arturia)mod strip CC 1, pitch strip = pitch bend snapping to centre, sustain CC 64; user channel set with Shift + key
community Spectrasonics — Setting up the KeyStep 37 (non-official)knob bank 1: CC 74, 71, 76, 77

Notes

Channel 1 and lowest key C3 (48) are assumptions (the manual leaves the defaults to MIDI Control Center); the keys follow any note on the channel, so an octave shift on the unit just scrolls the on-screen keys. Knob banks 2–4 are not mapped. The original 32-key KeyStep has the same strips and pedal: use this profile or generic-keys25/49.

Port names it recognises

matches: /keystep\s*37/i
prefers: /midi/i

Signals

Every control publishes midi/keystep37/<control> (0..1), plus /raw; pads add /hit, encoders /delta, keys /on /off and n<note>; the last control touched is midi/keystep37/last.

Use it

Use Arturia KeyStep 37 in your own work

Embed it with one line

No import map, no build step. Change layout, add hardware="ask" for a Connect button.

html

<script type="module" src="https://openaudiovisual.com/packages/midi/element.js"></script>
<oav-controller profile="arturia-keystep37" readout></oav-controller>

Or as an iframe

For places that only take an iframe. Every event arrives as a postMessage.

html

<iframe src="https://openaudiovisual.com/embed/controller/?profile=arturia-keystep37&readout"
        width="720" height="267" style="border:0;max-width:100%" allow="midi"
        title="Arturia KeyStep 37"></iframe>
<script>
  // every control the visitor plays arrives here
  addEventListener('message', (e) => {
    if (e.data?.source !== 'openav' || e.data.type !== 'control') return;
    console.log(e.data.detail.signal, e.data.detail.value);
  });
</script>

Send it to Ableton, TouchDesigner or Resolume
What you play on screen leaves as real MIDI on the IAC bus (macOS) or a loopMIDI port (Windows). The steps are on the catalog page.
html
```

<script type="module" src="https://openaudiovisual.com/packages/midi/element.js"></script>
<oav-controller profile="arturia-keystep37" midi-out="IAC" readout></oav-controller>

```
macOS: Audio MIDI Setup → MIDI Studio → IAC Driver → “Device is online”. Windows 11: the built-in Windows MIDI Services have a loopback (not tested by us); older Windows: install loopMIDI, add a port and use midi-out="loopMIDI".

In p5.js, with one line

The one-line injection names knobs, faders and pads by their order in this profile, the order of the table above. Add ?profile=arturia-keystep37 to make the on-screen controller this one; a real Arturia KeyStep 37 is recognised by its port name.

javascript

document.head.prepend(Object.assign(document.createElement('script'), { src: 'https://openaudiovisual.com/p5/oav-p5.js?profile=arturia-keystep37' }));

In your sketch	Control	Message
`knob1`	1 `k1`	CC 74 · Ch 1
`knob2`	2 `k2`	CC 71 · Ch 1
`knob3`	3 `k3`	CC 76 · Ch 1
`knob4`	4 `k4`	CC 77 · Ch 1
`notePressed(note, velocity)`	48–84 (C3–C6)	a key goes down

p5.js sketch

function draw() {
  background(knob1 * 255);   // 1 · CC 74
  circle(width / 2, height / 2, 50 + knob2 * 300);   // 2 · CC 71
}

function notePressed(note, velocity) {   // a key goes down
  circle(random(width), random(height), velocity * 100);
}

Encoders, buttons, wheels and strips are not numbered: read them as midi.cc[number] in the table above, or react in controlChange(cc, value, ch).

The whole p5.js page →

Around this controller

Arturia MiniLab 3Arturia · 8 pads · 25 keys · 8 knobs · 1 encoder · 4 faders · 2 touch strips
Arturia BeatStepArturia · 16 pads · 16 encoders
Korg nanoKEY2KORG · 25 keys · 2 buttons · 1 touch strip
Novation Launchkey Mini MK3Novation · 16 pads · 25 keys · 8 knobs · 2 touch strips
Novation Launchkey 25 MK4Novation · 16 pads · 25 keys · 8 knobs · 1 button · 2 wheels
Novation Launchkey 37 MK4Novation · 16 pads · 37 keys · 8 knobs · 1 button · 2 wheels

Compare Arturia KeyStep 37 with the rest, by keys, pads, knobs, faders and LED feedback →

Missing

Is your controller not here?

Open an issue with the brand and model, whether you have the unit and a link to the manual. Or write the profile yourself: it is one JSON file.

GitHub

Is something in this data wrong?

Every number on this page comes from one JSON file. If it disagrees with your unit or the manual, tell us which firmware you checked and we fix the file.

Arturia KeyStep 37