This page is read from MIDI Instrument Definitions, a Python library used in the author's other projects, in which every number is traced to a document its maker published. Its source is on GitHub.

Arturia AstroLab 37 MIDI implementation

The MIDI implementation of the Arturia AstroLab 37: what it answers to, and the 35 controls it offers, on firmware 2.0.0.

At a glance

Firmware: This page describes firmware 2.0.0.
MIDI channel: Any one of 1 to 16.
Parts: Part, 2 of them: each on a MIDI channel of its own, taking notes and controls.
Voices: Not recorded.
Note range: Not recorded.
Velocity: Not recorded.
Aftertouch: Not recorded.
Pitch bend: Not recorded.
Program change: Not recorded.
MIDI clock: Received.
Start and stop: Received.
Control change: 35 controls, in the tables below.
NRPN: Not recorded.
System exclusive: Not recorded.

Controls

In the order the definition gives them, by group. Under each control is the name a program calls it by, once pymidiinstrumentdefs.load("arturia/astrolab_37") has loaded them.

Controllers

Control	CC	Values
Mod Wheel `mod_wheel`	1	0-127

Master

Control	CC	Values
Master Volume `master_volume`	7	0-127 Neither sent nor received

Pedals

Control	CC	Values
Expression `expression`	11	0-127
Aux 1 `aux_1`	12	0-127
Aux 2 `aux_2`	13	0-127
Sustain `sustain`	64	0-127

Effects

Control	CC	Values
Reverb `reverb`	16	0-127
FX B `fx_b`	18	0-127
Delay `delay`	19	0-127
FX A `fx_a`	93	0-127

Macros

Control	CC	Values
Timbre `timbre`	71	0-127
Brightness `brightness`	74	0-127
Time `time`	76	0-127
Movement `movement`	77	0-127

Faders

Control	CC	Values
Fader 4 `fader_4`	72	0-127 Received, never sent
Fader 1 `fader_1`	73	0-127 Received, never sent
Fader 2 `fader_2`	75	0-127 Received, never sent
Fader 3 `fader_3`	79	0-127 Received, never sent
Fader 5 `fader_5`	80	0-127 Received, never sent
Fader 6 `fader_6`	81	0-127 Received, never sent
Fader 7 `fader_7`	82	0-127 Received, never sent
Fader 8 `fader_8`	83	0-127 Received, never sent
Fader 9 `fader_9`	85	0-127 Received, never sent

Functions

Control	CC	Values
Previous Preset `previous_preset`	102	0-127 Received, never sent
Next Preset `next_preset`	103	0-127 Received, never sent
Previous Song `previous_song`	104	0-127 Received, never sent
Next Song `next_song`	105	0-127 Received, never sent
Arp On/Off `arp_on_off`	106	0-127 Received, never sent
Arp Hold `arp_hold`	107	0-127 Received, never sent
Tap Tempo `tap_tempo`	110	0-127 Received, never sent
Rotary Fast On/Off `rotary_fast_on_off`	111	0-127 Received, never sent
FX A On/Off `fx_a_on_off`	112	0-127 Received, never sent
FX B On/Off `fx_b_on_off`	113	0-127 Received, never sent
Delay On/Off `delay_on_off`	114	0-127 Received, never sent
Reverb On/Off `reverb_on_off`	115	0-127 Received, never sent

Where these facts come from

Source documents

User Manual AstroLab 37, 2.0.0, dated 6 October 2026, its user manual, read on 10 October 2026 (the file read).
User Manual AstroLab 37, 1.0.0, its user manual, read on 10 October 2026 (the file read).
AstroLab 37 firmware release notes, through 2.0.0, 2.0.0, dated 1 October 2026, its release notes, read on 10 October 2026 (the file read).
Arturia - AstroLab, its download page, read on 10 October 2026 (the file read).

How they were read

THE ASTROLAB 37 HAS A MANUAL OF ITS OWN, AND ITS TABLE IS THE 61'S LESS TWO ROWS. The User Manual AstroLab 37, edition 2.0.0, prints "11.3. AstroLab 37 MIDI Implementation" (manual p. 91) over two pages (manual pp. 91-92), under "Section Parameter MIDI CC Sending Receiving" (manual p. 91): thirty-five rows from Mod Wheel on 1 to Reverb On/Off on 115. It is arturia/astrolab's table for the 61 and the 88 without Start Record on 108 and Play / Stop on 109, every other row alike in all five columns, the Section column's six labels and its stray n/a. on Fader 1 included. The two missing rows are the looper's, and this manual describes no looper. Arturia publishes no MIDI implementation document for it; its other documents are cheat sheets.

THE 1.0.0 MANUAL PRINTS THE SAME THIRTY-FIVE ROWS. The edition before, which Arturia still serves and has served under that number as three different files, prints the same table (manual_1_0_0 pp. 81-82) in the one file read, the third, revised in July 2026 - so the map has not changed between that file and the one written for firmware 2.0.0.

THE SECTION COLUMN IS NOT A GROUPING, AS ON THE 61. Six rows carry a label and the rest leave the cell blank, in controller-number order, so the groups below come from what the manual's body says each control is, exactly as in arturia/astrolab.

THE FOUR DIRECTION WORDS, READ AS THE 61'S ARE. No page defines them. Always and Never are plain; n/a appears only against the nine Faders, Fader 1's printed n/a.; and Not linked is read from what Link does: "Changes made in AstroLab 37’s Macro and Effects controls are sent to Analog Lab." (manual p. 93), and the seven Not linked rows are exactly the four Macros, FX A, FX B and Reverb. The MIDI Out Filter fits it: "Auto When AstroLab 37 and Analog Lab are Linked, the MIDI Out Filter switches to Keyboard Only." (manual p. 29), where "Keyboard only Only the notes played on the AstroLab 37 keyboard are transmitted via MIDI Out." (manual p. 29). So a Not linked row is read as sent as a controller whenever the instrument is not mirroring its software, and is both; taken literally, the Filter's note-only wording would silence the Always rows too, so it is not read that far. Why Delay on 19 is Always where Reverb on 16, its fellow send, is Not linked, no page says. This manual adds a switch the 61's lacks: "Knob Send CC When On, turning a knob in AstroLab 37 will send a MIDI Control Change message." (manual p. 29). The counts: 13 both, 21 receives, and Master Volume on 7, printed Never and Never and carried with direction: none, as on the 61.

THREE PEDAL ROWS, ONE PEDAL INPUT. The table prints Expression on 11, Aux 1 on 12 and Aux 2 on 13 as Always sent and Always received. But the rear panel's only pedal jack is "Sustain Pedal input" (manual p. 16), which "Accepts sustain pedal with TS or TRS connector" (manual p. 16), and the feature list names "Sustain Pedal input." (manual p. 12) and no other. The body mentions an Aux pedal once, in the Arpeggiator - "Hold can also be activated by the Sustain pedal or added as a function to an Aux pedal." (manual p. 63) - and a Part's switches include the "Expression Pedal" (manual p. 36), both as on the 61. So the three rows are carried as printed, and that this instrument sends them is doubted here: nothing on it is described that could. A controller on the USB-A port, which can play AstroLab 37, is one way they could arrive.

FOUR CONTROLLER NUMBERS ARE STATED TWICE, AS ON THE 61. "The MIDI Continuous Controller (CC) messages sent by the Macro knobs are, left to right: 74, 71, 76, and 77." (manual p. 40), against "The four Macro knobs are Brightness, Timbre, Time, and Movement" (manual p. 40); the table gives Brightness 74, Timbre 71, Time 76 and Movement 77, and the two agree on the numbers. The note says they are sent with no condition, where the table marks all four Not linked and Knob Send CC can be turned off; the definition follows the table.

NINE FADERS THE MANUAL DOES NOT EXPLAIN. Fader 1 to Fader 9 take 73, 75, 79, 72, 80, 81, 82, 83 and 85, each n/a sending and Always receiving. The word appears elsewhere only as the Sound Edit icon of "3 faders" (manual p. 41) and as display names on one instrument's Sound Edit page in the appendix (manual p. 109), neither of which is these controls. They are below as published, and what they are is left unrecorded.

ONE CHANNEL FOR A SECOND CONTROLLER, AND A CHANNEL PAIR FOR EACH PART. The keyboard's own channel is fixed - "Main MIDI Channel This is the channel where the AstroLab 37 keyboard in sending data. This cannot be changed." (manual p. 28), the maker's own wording - while the "Secondary MIDI Channel" (manual p. 28) "selects the receive channel for a connected MIDI controller (1–16 or All), which can be seen as the secondary keyboard." (manual p. 28). Each Part has its own: "Part 1: Here you can set the Low Note and High Note limits, MIDI input and output channels, and Octave and Semitone Transpose." (manual p. 36). So the two Parts are one part, channel: assigned, as on the 61 - a section, MIDI and Splits, that the 1.0.0 manual does not have. The manual says the transmit channel two ways, as the 61's does: fixed on p. 28, and settable as "Keyboard Channel Here you can set the MIDI Output channel of the AstroLab 37" (manual p. 29). Nothing here records a transmit channel. And it says the receive channels two ways: the Secondary MIDI Channel "filters out all incoming data and only allows MIDI messages corresponding to the selected channel." (manual p. 28), while each Part has its own input channel and B-3 V presets need three channels at once, the upper keyboard on 1, the lower on 2 and the pedals on 3 (manual p. 29). channels records 1 to 16, the one range printed, the Secondary channel's, without its All; the Parts' range is not printed.

POLYPHONY BELONGS TO THE LOADED ENGINE, FROM 1 TO 48, AND THE PARTS DO NOT SHARE: "These are voices per part, meaning that if you load, for example, a Multi consisting of a Mini V and Prophet-5 V, you can play 16 voices on each part." (manual p. 39). The manual's own figures disagree in places - the example's Mini V is listed at 6 voices (manual p. 37), and a later page gives "8 voices for poly synths" (manual p. 96) against a table with 16, 12, 6 and 4 - and the 2.0.0 notes change Synthx and Sampler polyphony. No figure is recorded, and polyphony_shared is false.

CHANNEL AFTERTOUCH, STATED THIS TIME, AND OF THE KEYS: "AstroLab 37’s keyboard features 37 Slim Keys that sense both velocity and channel aftertouch." (manual p. 17). The 61's manual leaves the word unqualified; this one does not. It is said of the keyboard. Each Part has a switch for whether it is affected by aftertouch (manual p. 36), which is a setting, and no page says that an aftertouch message arriving over MIDI is used, so aftertouch is not recorded. Until 2026-10-14 it said channel, the keys' kind.

CLOCK IS RECEIVED, AND START IS SAID ONCE. "USB: AstroLab 37 syncs to incoming MIDI clock over USB." (manual p. 62) and "MIDI: AstroLab 37 syncs to incoming MIDI clock over the 5-pin MIDI input." (manual p. 62), with "If a MIDI start message is detected, playback resumes synced to the external clock." (manual p. 62). Clock is followed only when "Tempo Sync: This toggle enables or disables syncing tempo to external devices." (manual p. 27) is on. The start sentence is the only one about transport, under Auto sync, and "playback" there names nothing this manual describes - it reads as left from the 61's looper text, whose stop sentence this manual drops - so transport: receives is carried and doubted. No page says either is sent, and the MIDI Out Filter's widest setting transmits notes.

NOT RECORDED: program change, which neither this manual nor the 37's release notes mention - the 61's evidence for it is its own release notes, from versions before the 37's first, and the resources page's "MIDI program change support" (resources_page) is in a blurb about the AstroLab 1.5 update; how incoming velocity and aftertouch are treated, since the keys "sense both velocity and channel aftertouch" (manual p. 17) and no page says what an incoming velocity or aftertouch does; the note range; pitch bend's range and whether it can be set, a Part's switch turning bend on or off (manual p. 36) being neither, so pitch_bend is left out; mode, system exclusive and NRPN, which no page mentions.