KeyLabLive

An Ableton Live control surface script (MIDI remote script) for the Arturia KeyLab 61 and 88 mk3, built for playing live rather than for producing.

Up to eight instrument tracks sharing one preset list on the keyboard's screen, your Arrangement locators as a song list, and no Max for Live anywhere.

• The screen buttons arm and un-arm your tracks — always, including while a preset list is open. Tracks 1-4 are on buttons 1-4, tracks 5-8 on buttons 5-8. The label is the track's name — or, once you have chosen one, the preset it is playing.
• Hold a screen button to open the preset list for that track. Pick with the jog wheel, Play or Back/Forward; Stop closes the list without picking. That button turns yellow for as long as its list is on screen — hold a different button and the list, and the yellow, move to that track.
• The middle of the screen lists your Arrangement locators, and follows as you add, rename, move or delete them. The jog wheel moves the cursor, Play jumps to that song and starts it, Stop stops.
• Playback stops automatically just before the next locator, and the cursor moves on, ready for the next song.
• The faders set track volume, one fader per track.
• Cycle rebuilds the preset list from your Collection.
• Tap and Metro are tap tempo and the metronome. While a preset list is open they step between chapters instead, once you have sorted your presets into any.
• Record, Save, Undo, Redo and Quantize do what they do in Live — see The other buttons below.
• The pads are dark and do nothing, unless you switch on clip launch — see Clip launch below.
• The encoders are not used. The script does not touch them.

Know this before you build a set around it: choosing a preset reloads the instrument. Held notes are cut, and a large sampled instrument takes as long to load as it takes. That is inherent to preset files, not a shortcoming of the script, and it cannot be coded away. Change presets between songs or between sections — not in the middle of a phrase. Two heavy sounds that have to alternate within one song still belong on two separate tracks.

Requires nothing but Live. No Max for Live licence, no companion devices, no other software.

Tested on a KeyLab 61 and 88 mk3 with Live 12 on macOS. The SysEx is identical on both sizes; only the MIDI port name differs. Live 11 is untested and runs a different Python version.

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What you get

KeyLabLive.als           a ready-made Live set: four tracks, seven locators
KeyLabLive/              the script — this folder goes into Remote Scripts
  __init__.py
  keylab_config.py       every setting you are meant to change
  keylab_live.py         the control surface
  keylab_presets.py      the preset list and hot-swapping
  keylab_repertoire.py   the song list
  keylab_session.py      clip launch on the pads, off until you switch it on
  keylab_screen.py       the keyboard's protocol — do not edit
  presets.txt            rebuilt from your Collection on every Cycle
  presets-manual.txt     your own list — the script never writes to it
LICENSE                  MIT — use it, change it, pass it on

keylab_config.py is the only file you need to open. It holds the track limit, the Collection name, the colours and the timings, each with a comment saying what it does.

keylab_screen.py is the opposite: not settings but measured facts about the hardware — SysEx layouts, CC numbers, LED ids. Changing something there does not reconfigure anything, it stops the screen working. It is documented so you can read it, not so you can tune it.

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Setting up

Six steps, in the order you will actually do them. One of them cannot move: the script folder must be in place before Live starts, or it will not be in the dropdown to choose.

KeyLabLive.als, next to the script folder, is a set with the tracks and locators already there: open that and skip to step 2. It was saved in Live 12.4 Suite and needs Live 12.4 or newer to open.

1. Build the Live set

One MIDI track for each instrument you want under your fingers, each with one instrument on it. Any instrument — it gets replaced the moment you pick a preset. The script works by track position, not by name: it takes the first tracks in the set, up to eight, one per screen button. Add or remove a track later and the buttons, the faders and the labels follow without a restart.

That is worth saying plainly: a track here is a slot, not an instrument. It becomes whatever preset you load into it. Nothing in the script cares what a track is called, which is just as well, because Live renames an un-renamed track after whatever device it now holds.

Then add locators in the Arrangement, one at the start of each song. Their names become the song list. There is no separate file to maintain.

Save the set. Nothing is stored inside it, but you want it on disk before you start restarting Live around it.

2. Install the script

Copy the KeyLabLive folder — the one next to this README, with the .py files in it — into:

Platform	Folder
macOS	~/Music/Ableton/User Library/Remote Scripts/
Windows	Documents\Ableton\User Library\Remote Scripts\

The folder name is what appears in Live's dropdown, so if you rename it, that is the name you will be looking for.

3. Restart Live

Live scans the Remote Scripts folder once, at startup. A script copied in while Live is running is not there as far as Live is concerned.

4. Choose the control surface

Preferences → Link, Tempo & MIDI. In the Control Surface table, pick an empty row:

Setting	Value
Control Surface	KeyLabLive
Input	KeyLab mk3 (DAW)
Output	KeyLab mk3 (DAW)

There are two ports per keyboard. The plain one carries the keys; the DAW one carries the screen, the transport buttons and the jog wheel. Their names differ by only a few characters — pick the DAW port in both dropdowns.

Set Arturia's own control surface to None in any other row that mentions the KeyLab. It writes track names to the same buttons this script writes to, and it sends a disconnect when you switch it off. Leave both enabled and they fight over the screen; you will see a mix of the two and conclude your own setup works when it does not.

5. Put the keyboard in DAW mode

This is the step that decides whether anything appears on the screen at all.

The keyboard has two independent worlds: Arturia mode (what Analog Lab uses) and DAW mode. They use different SysEx families and different CC numbers, and packets from one are ignored while the other is displayed. This script speaks DAW mode only.

Switch with the physical keys: Prog + screen button 6. (Prog + screen button 5 goes back.)

There is no SysEx that changes the mode. The script does send a connect handshake at startup, but that only works when the unit is already in DAW mode. It is a handshake, not a mode switch.

How to tell you are in DAW mode: the screen buttons send CC 45-52. In Arturia mode the same buttons send CC 56-63.

By now the screen buttons should carry your track names and the middle of the screen your locators. If not, go to When something does not work.

6. Tag a preset or two, then press Cycle

Live's Collections are the coloured labels at the top of the browser sidebar. This script uses one of them, for all your tracks together.

1. Right-click any one Collection and rename it Presets. Which colour it happens to be does not matter — the script looks it up by name. (Prefer a different name? Change PRESET_COLLECTION in keylab_config.py.)
2. Find a preset in the browser and tag it with that Collection. Right-click → the Collection's name, or select the preset and press the Collection's number — the number is much faster when you are tagging a row of them.

Then press Cycle, the button left of Play. It rebuilds the browser index, writes presets.txt from the Collection, and reloads it. The button goes amber while it works and flashes blue when it is done. Your first Cycle replaces whatever presets.txt arrived in the folder.

Now hold a screen button: the list is there.

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Your preset lists

The list on screen is built from two files, which do the same job from opposite ends. Keeping them apart is what makes both of them safe.

	presets-manual.txt	presets.txt
Who writes it	you, only ever you	the script, on every Cycle
Where it looks a preset up	the browser at large	your Collection
Tagging needed	no	yes
On screen	first	after the manual list

presets-manual.txt needs nothing set up. It ships with a starting list of 197 presets in five chapters, so the script has something to show the first time you open it. Not every chapter exists in every edition of Live: Drift is in all of them, Analog and Electric need Standard or Suite, and Operator needs Suite. Those presets were picked to demonstrate what the system does, not because they are the best sounds in Live — delete the lines you do not play.

The Collection is for what you tag in and out as you work, which is where most of your list will come from once you are past the first evening.

One list for every track is deliberate. A track becomes whatever you load into it, so a preset does not belong to a particular track and there is nothing to divide up — and your other six Collections stay yours. A Collection holds a reference, not a copy: your presets stay where they are, and the index stays a dozen entries long instead of thirty thousand, which is why Cycle answers instantly.

Anything Live's own hot-swap accepts in an instrument slot works: Live's instruments, Instrument Racks, Sounds, Packs and plugin presets.

The line format

One line per preset, in both files:

Grand Piano, Racks
E-Piano Roads, Racks
Wurli Classic Piano, Electric
Bloom Pad

The first field is the preset's name in Live's browser. Leave it alone — it is how the preset is found. The second is the chapter, and it is yours. A line with no comma is simply a preset with no chapter. Chapters are shared between the two files: Racks in one and Racks in the other is one chapter.

Reorder the lines and the order sticks. Presets newly tagged land at the end with no chapter, so the order you know never shuffles under your fingers. A preset in both files is shown once, from the manual file — that is the one you edited on purpose, so it decides the chapter and the place.

Untagging does not throw your work away

The line moves to a block at the bottom of presets.txt marked #~:

# ---------------------------------------------------------------
# Remembered: tagged once, not tagged now.
# ---------------------------------------------------------------
#~ E-Piano Roads, Racks

It is not in the list and not on screen — untagged means gone. But tag it again and it comes straight back with its chapter intact. Delete the line yourself to forget it for good.

That also means you can write a list of chapters before you have tagged anything. Presets you have not got round to tagging sit in the remembered block and climb back up one by one as you tag them, instead of being wiped at the next Cycle. A preset that is never going to be tagged belongs in presets-manual.txt instead, where it is on the list straight away.

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Chapters

A preset file with forty entries is fine at home and miserable between two songs. Chapters cut it into lists you can cross in a few clicks.

Put a chapter name after any preset and it appears. Give no preset a chapter and there are no chapters at all — one flat list, exactly as if the feature did not exist, and Tap and Metro go nearly dark while a list is open. This is the normal state for anyone who has never opened the file.

• Tap is the previous chapter, Metro the next — while a preset list is open, and only then. They light blue when there are chapters to move between. With no list open they are tap tempo and the metronome, as printed.
• Two things say the chapter buttons are there, because nothing is printed on the keyboard to tell you: the list's title reads < Racks 2/4 >, where the arrows point at Tap and Metro at the two ends of the transport row and the count says whether pressing one is worth it — and when a list opens, both buttons blink three times, which touching either one cuts short.
• Past the last chapter is the first again. Set CHAPTER_WRAP = False if you would rather the ends were ends.
• Chapters appear in the order they first appear in the file. There is no separate list of them to keep tidy.
• A preset with no chapter takes the name of the file it came from, so the title on screen says where it came from: Collection for one you tagged, Other for a hand-written line you left blank. Newly tagged presets arrive with no chapter, so they gather under Collection until you sort them — tag first, sort later.
• Each chapter remembers where you left its cursor, and each track remembers which chapter it was last looking at. Open a list and you are where you were. After Live restarts, a track's chapter comes back from whichever preset is actually sitting on it; nothing is stored in the set.
• A chapter change loads nothing. It is navigation, not a choice — which is why Back and Forward kept their job of stepping the cursor and loading what they land on after a short pause, so you can step past two or three presets and hear the one you stop at. Handing them to chapters would have cost you the only way to audition.

CHAPTER_TITLE_ARROWS, CHAPTER_PULSES, CHAPTER_PULSE_SECONDS, CHAPTER_TAGGED and CHAPTER_UNNAMED in keylab_config.py turn each of these down, off, or into your own words.

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Day to day

Press Cycle after tagging a preset, or after editing either preset file. Both files and the index are read once at startup. Nothing else needs Live restarted.

Put what you reach for during a song near the top of its chapter. The list is crossed with the jog wheel or Back/Forward, one line at a time, so the top of a chapter is the short walk.

You can see which list you are driving without reading the screen. The locator list is what stands there; the preset list only exists while you have opened it, and the screen falls back to the locators by itself once you have chosen. While a preset list is open, Play turns amber, Back and Forward turn yellow and Tap and Metro turn blue. They all go back to their own colours when it closes.

Screen buttons show 12 characters. Longer preset names are cut when the button is drawn — at a word boundary if one falls near the end, mid-word otherwise, so Organ Transi tells you which organ where Organ would not. The list itself is not cut; it shows names in full. If a button matters more to you than that, save your own copy of the preset in Live under a shorter name — a factory preset cannot be renamed where it lies.

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The other buttons

• Tap is tap tempo and Metro switches the metronome, lit while it is on. Both hand over to chapters while a preset list is open — see Chapters.
• Save is Capture MIDI, as in Arturia's own script: it keeps what you just played without having been recording. Bright blue when Live has something to capture, dim when it has not.
• Undo and Redo are Live's own, and light up when there is something to undo or redo.
• Quantize quantizes the clip open in Live's detail view to 1/16.
• Record is Live's Arrangement Record: dim red at rest, bright red while recording. With clip launch switched on it is a shift key instead, and no longer records.
• The pads are dark and do nothing unless clip launch is switched on.
• The encoders are not used. The script does not touch them.

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Clip launch

Off as it comes. Set SESSION_GRID = True in keylab_config.py and restart Live, and pads 1-12 become a 4x3 window onto Session View: four tracks across, three scenes up, starting at the first track and the first scene. Live draws its own highlight rectangle around the slots the pads address.

Read this before you switch it on. The window starts on the same tracks the screen buttons arm, and an empty slot on an armed track is record-ready. Pressing that pad starts a recording, and with it the transport. If your songs live in the Arrangement, one stray hit on a pad sets Live playing. That is why it is off: a pad that does nothing cannot go wrong on stage.

• Press a pad to launch that slot, exactly as clicking it in Live would.
• Record becomes a shift key and stops being Record.
• Hold Record and press a pad to delete that slot's clip. No confirmation — Undo is the safety net.
• Hold Record and turn the jog wheel to move the window across scenes; hold Record and press Back/Forward to move it across tracks.

Pad	Means
nearly dark	empty slot
dim red	empty slot on an armed track — pressing it records
the clip's own colour, dim	a clip, not playing
bright green	playing
bright red	recording
half green / half red	about to start, waiting for the next quantization point

Every one of those colours, and how dim "dim" is (SESSION_STOPPED_DIM), is in keylab_config.py.

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When something does not work

Work down this list. It is ordered by how often each one is the answer.

1. Is the keyboard in DAW mode? Prog + screen button 6. Nothing at all appears on the screen otherwise.

2. Is Arturia's own control surface set to None? If it was on, it may have sent a disconnect on its way out — restart Live afterwards.

3. Was the folder in place before Live started? Copying it in while Live is running is not enough, and neither is changing the dropdown without a restart. A remote script only receives the notes and CCs it asked Live to forward, and it asks at startup. This bites during setup and never again.

4. Are both Input and Output set to the DAW port? They are separate settings, and working buttons prove nothing about the output path.

5. Did you press Cycle? A preset tagged after Live started is not in the index until you do.

6. Is the Collection spelled the way PRESET_COLLECTION says? It must match exactly. An empty or missing Collection leaves presets.txt untouched rather than wiping it — a Collection that comes back empty is far more often a typo than a list you meant to empty. Live's Log.txt has a line for it at startup:

   KeyLabLive/presets: root 'colors/Presets': 12 preset(s)
   

7. Are the manual lines spelled the way your browser spells them? A line that stays quiet names a preset you do not have, or names it differently. The log lists them:

   KeyLabLive/presets: 3 manual preset(s) still not found: grand piano | ...
   

   If every manual line is missing, PRESET_SEARCH_ROOTS in keylab_config.py is empty — with no search roots, only tagged presets are found.

8. Did a preset fail to load? The screen says Failed and the log says why. not in the browser means the name or the Collection is wrong, and the log then prints the closest matches it does have.

My list is much shorter than someone else's. The list is built from your own Live browser, so it holds what you have installed and nothing more. Live Standard has fewer instruments than Suite, and a Pack you chose not to install is a Pack whose presets are not there. That is why the list in presets-manual.txt is longer on some machines than others.

A fader does nothing. Live can swallow it before the script sees it, if it happens to be MIDI-mapped in the set. It looks exactly like a dead fader.

The screen readout ignores me when I nudge a fader. Not a bug, and not the script. The keyboard's own readout is triggered by capacitive skin contact, not by the value changing. A fingernail, or a sheet of paper between finger and fader, produces no readout at all — while the value is still sent and the sound still follows.

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Making it your own

Everything below is in keylab_config.py.

Fewer tracks — lower MAX_TRACKS. It comes set to 8, one per screen button, and the script takes the first tracks in the set up to that number. Set it to 4 to keep the script off track 5 and up.

A different Collection — change PRESET_COLLECTION. It does not have to be a Collection at all: PRESET_ROOT_FORMAT can point at a User Library folder or one of your own Places instead.

A hand-written preset list — set PRESET_FILES_AUTO = False and presets.txt is left entirely to you. Cycle then only rebuilds the index.

How wide the manual list searches — PRESET_SEARCH_ROOTS. Manual names are looked up in the parts of the browser it names, but only the names your file actually asks for are indexed: a hundred hand-written names cost a hundred entries however large your library is, and the search stops the moment the last one is found. The walk happens at startup and on Cycle, never while you are playing. If Cycle feels slow, cut the setting down or empty it.

When playback stops — STOP_LEAD_MS, default 200. Playback halts that far before the next locator, because stopping exactly on it occasionally lets a fragment of the next song through. Raise it if you still hear one; lower it if songs feel clipped.

How long a hold takes — LONG_PRESS_SECONDS, default 0.4.

Colours — all of them, as (red, green, blue) with each 0-127. Note that is not 0-255. No "off" state is fully dark: a button you cannot find on a dark stage is worse than one showing the wrong state.

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Credit

The code and the comments in it were written by Claude, Anthropic's AI model. The idea, the design decisions, the measurements and the testing on real hardware are the author's.

The SysEx protocol was reverse-engineered with a MIDI monitor against real hardware. The full notes, including how each packet was measured, are here:

https://github.com/saxofonbrian/keylab-mk3-sysex

Arturia does not publish the source of the KeyLab mk3 script; it ships compiled inside Live. Two facts were read out of it rather than measured: the CC numbers of Save, Quantize, Undo and Redo, and that Save there means Capture MIDI. Everything else was measured on the hardware, and none of its code is used here.