FM-1 firmware · v0.24

ChoralRoot

Stable 0.24 replaces 0.23 and the three betas as the installer default; the Classic chord-key layout stays the default.

Turns it into: A chord-playing instrument with two parts, seven engines, performance patterns and looped chords
Best for: Chord-led playing and building loops
Install: GitHub release or hub

Where everything is on ChoralRoot

TapSwipe across the panel, then tap any control to see what it does on ChoralRoot.

On every button on ChoralRoot: HOLD MENU COMBO. Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.On every button on ChoralRoot: EDIT: LONG SECTION HOLD. Has no separate long-hold action in the sound editor.

Printable skin (PDF)Key strips (PDF)

Start here

ChoralRoot makes the FM-1 a chord instrument: choose a root with one hand and shape its chord with the other. A second sound supplies bass, performance modes spread the chord into notes, and a looper stores chord gestures. FM6, FM TONE, VA, CZ-1, P5, WHEEL and GRAIN supply the sounds.

Refreshed to 0.24 (stable): an independent checker found zero errors in round 2 (2026-10-17). Nothing here was tested on a unit.

This guide comes from reading the tagged source. Nothing here was tested on a unit. The JSON carries each entry’s evidence. Page-specific behavior takes priority over shared gestures; musical contexts can apply on several screens.

Panel names below are the printed names. SEL is KEY, ENV is BASS, LFO is LATCH in Classic or LOCK in FM-1, GLO is OPT, ARP is PERF and PLAY is LOOP. A tap normally takes effect when you release the button. The ordinary hold threshold is set in Options, from 300 to 600 ms; HOME uses 600 ms. The encoders turn without a push action.

The modes

Mode or page	How to get there	What it holds
Home	Press HOME.	Play chords and notes while the chosen view follows them.
Full keyboard	KEY page 2: turn KNOB 2 right.	Every key is musical unless Full K Shorts reserves F#5/G5, with Key Mode and the shortcut’s chord switch choosing notes or chords, bass splits retained, and KNOB 1 changing voicing.
KEY layer	Hold SEL.	Two pages set key, scale and keyboard behavior.
KEY keys play	Tap GLO in the KEY layer.	KEY retains its page controls while the keybed plays.
Performance	Hold ARP.	Choose a performance mode and edit its four settings.
FX layer	Hold FX.	Eight pages set sends and effects.
Bass layer	Hold ENV.	Set bass behavior, register, sound and level.
Sound browser	Hold EDIT from any screen, or turn PRESETS while the sound editor is open.	Preview an engine and its sounds before keeping or canceling.
Engine hold	Hold GLO and turn PRESETS or ALGORITHM where it picks a sound.	Choose the part’s engine and apply it when GLO is released.
Metronome	Hold SEQ outside the sound and loop editors.	Choose a time signature and click level.
PLAY menu	Hold PLAY or cycle SEQ to the PLAY menu.	Two pages set loop recording and playback behavior.
PLAY keys play	Tap GLO in the PLAY menu until Keys is Play.	PLAY retains its page controls while the keybed plays.
Loop editor	Tap EDIT in the PLAY menu or use SEQ.	Change the loop’s chord events and step settings on its editing grid.
LOCK layer	Hold B3 with Classic chord keys active, or hold LFO in the FM-1 layout, outside the sound editor.	Set how type and extension keys replace a locked chord.
View menu	Hold HOME alone.	Choose a view and set its lock.
Options	Tap GLO outside KEY, PLAY and the sound editor.	SELECT chooses a setting and KNOB 1 changes it.
Save menu	Tap SAVE.	Save a sound and set its favorite, filter and type values.
Sound naming	Choose Save as new and confirm.	Enter the sound’s name and confirm its save.
Delete ask	Hold SAVE for one second in the sound-save dialog.	Confirm deleting a user sound or restoring a factory sound.
Step entry	Choose Step recording and press REC.	Enter one chord per sixteenth-note step.
Calibration	Choose Options > Calibrate and press OCT+, or hold OCT- and OCT+ while switching on.	Assign the printed buttons and encoder directions; thirty seconds without input cancels and discards the unfinished calibration.
Safe mode	Starts automatically after two successive crash or watchdog resets before the 30-second settling point; a power-on clears that count.	Flash records are skipped and recovery controls remain available.
Startup	Switch the unit on.	Start-up gestures and the initial stripe display.
Sound editor	Tap EDIT for chords or hold ENV and tap EDIT for bass.	Choose a section, screen and lane to edit four cells.
Overwrite recording	Choose Overwrite with ALGORITHM in the PLAY menu or cycle GLO+REC.	REC follows this record mode.
Advance recording	Choose Advance with ALGORITHM in the PLAY menu or cycle GLO+REC.	REC follows this record mode.
Overdub recording	Choose Overdub with ALGORITHM in the PLAY menu or cycle GLO+REC.	REC follows this record mode.
Replace recording	Choose Replace with ALGORITHM in the PLAY menu or cycle GLO+REC.	REC follows this record mode.
KEY page 1	Hold SEL and turn SELECT left for page 1 or right for page 2.	Key and keyboard settings.
KEY page 2	Hold SEL and turn SELECT left for page 1 or right for page 2.	Key and keyboard settings.
Strum performance	Hold ARP and choose the mode with SELECT.	The performance mode’s four parameters.
Slop performance	Hold ARP and choose the mode with SELECT.	The performance mode’s four parameters.
Arp performance	Hold ARP and choose the mode with SELECT.	The performance mode’s four parameters.
Pattern performance	Hold ARP and choose the mode with SELECT.	The performance mode’s four parameters.
Harp performance	Hold ARP and choose the mode with SELECT.	The performance mode’s four parameters.
FX sends	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX reverb 1	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX reverb 2	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX chorus	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX delay 1	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX delay 2	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX drive	Hold FX and choose the page with SELECT.	Four controls for this FX page.
FX filter	Hold FX and choose the page with SELECT.	Four controls for this FX page.
PLAY page 1	Open the PLAY menu and turn SELECT left for page 1 or right for page 2.	Loop recording and playback settings.
PLAY page 2	Open the PLAY menu and turn SELECT left for page 1 or right for page 2.	Loop recording and playback settings.
Loop editor 1	Open the loop editor and turn SELECT left for page 1 or right for page 2.	Step properties.
Loop editor 2	Open the loop editor and turn SELECT left for page 1 or right for page 2.	Step properties.
Count-in	Press OCT- and OCT+ together.	Shows remaining count-in beats in red with a progress ring.
Undo result	Press OCT- and OCT+ together.	Shows remaining recording layers and an undo ring.
Panic	Press OCT- and OCT+ together.	Shows PANIC in red while the panel lights flash.
Idle stripes	Press OCT- and OCT+ together.	Shows moving stripes at startup or after three idle minutes.
Knob readout	Press OCT- and OCT+ together.	Shows the changed value, parameter name and meter over the current page.
Chord	Choose this view in the HOME hold menu.	Shows the chord name, notes, voicing and optional degree.
Keyboard	Choose this view in the HOME hold menu.	Shows the chord and its notes on a keyboard drawing.
Notes	Choose this view in the HOME hold menu.	Lists voiced note names.
Geek Out	Choose this view in the HOME hold menu.	Shows the chord name, note list and keyboard, voicing, play style, bass state, tempo and audio, core or boot diagnostics.
Scope	Choose this view in the HOME hold menu.	Draws the audio waveform with the chord above it.
Geek Out 2	Choose this view in the HOME hold menu.	Shows two-core load, RAM and pool-memory meters.
FM-1 chord keys	Options > Chord Keys: FM-1, with Keyboard Chords or F#5 restoring the chord keys.	Uses seven low modifier keys and C4–G5 as roots, except where a picker or naming takes the roots.
FM-1: KEY Pick	Choose Chord Keys FM-1, hold SEL, then use GLO until the keys pick.	G#3/A#3 choose the scale; D4–G5 choose the tonic; all other low keys have no pick action.
Full keyboard shortcuts	Options > Full K Shorts: On, then KEY page 2 > Keyboard: Full.	F#5 restores the active layout’s low chord keys; G5 changes the Full keyboard between chords and notes; both switch at press and restore their prior state after a long hold. Musical entries apply where keys play; picker and naming maps retain their jobs, except F#5/G5 switch everywhere outside KEY Pick.
Full: chord keys restored	With Full K Shorts On and Keyboard Full, press F#5.	The selected layout’s low chord keys return and roots stop at F5; F#5/G5 keep their switch jobs.
Options: Chord Keys	Tap GLO, then turn SELECT to Chord Keys.	Chooses Classic, the default for fresh settings, records written by 0.23 or the pre-layout betas, and Reset Settings, or FM-1, releasing held keys when changed while keeping the LOCK latch and moving its lights.
Options: SUS Window	Tap GLO, then turn SELECT to SUS Window.	Sets the FM-1 type-key combination window from 30 to 80 ms in 5 ms steps, starting at 30 ms; Classic hides this row.
Options: Full K Shorts	Tap GLO, then turn SELECT to Full K Shorts.	Enables F#5/G5 switches while Keyboard is Full, with Off as the default.
Options: MIDI Keys	Tap GLO, then turn SELECT to MIDI Keys.	Chooses Off or a key-control channel from 1 to 16, skipping MIDI Perform and MIDI Bass channels.
FM-1 layout active	Options > Chord Keys: FM-1, with either Keyboard setting.	LFO and GLO use the FM-1 layout’s LOCK and LATCH jobs, and LFO shows their state, including on Full keyboard; the sound editor keeps its section controls.

Play and pick sounds

Key Touch starts at Fixed; dynamic touch is opt-in.

Classic is the default chord-key layout: F3, G3, A3 and C4 select 6, m7, M7 and 9; F#3, G#3, A#3 and C#4 choose DIM, MIN, MAJ and SUS. B3 is LOCK and D4–G5 are roots. The optional FM-1 layout below changes the low keys. Full keyboard makes every key musical unless Full K Shorts reserves F#5/G5.

Hold a type or extension and play a root. LOCK can keep those choices after release; LFO latches the sounding notes. The KEY menu can make its keys select a tonic or play, and its Full keyboard setting changes the keybed split.

With Key Mode off, a root alone plays one note; a held or locked type makes its chord, and extensions need a type. Tap SEL to enable Key Mode. With Key plays set to Chords, each pitch chooses a chord relative to the tonic. Only Major and natural Minor are available. In degree order their default qualities are major/minor/minor/major/major/minor/diminished and minor/diminished/major/minor/minor/major/major. The keybed keeps its physical pitches; white keys do not become a row of scale degrees. Pitch mapping, chord building.

Do this	What happens
Hold F3	Adds the sixth to roots played while held only when a chord comes from a held or locked type or enabled Key Mode in Chords mode, with Advanced and Free also updating sounding chords.
Hold G3	Adds the minor-seventh to roots played while held only when a chord comes from a held or locked type or enabled Key Mode in Chords mode, with Advanced and Free also updating sounding chords.
Hold A3	Adds the major-seventh to roots played while held only when a chord comes from a held or locked type or enabled Key Mode in Chords mode, with Advanced and Free also updating sounding chords.
Hold C4	With Classic chord keys active, adds the ninth to roots played while held only when a chord comes from a held or locked type or enabled Key Mode in Chords mode, with Advanced and Free also updating sounding chords.

The table covers every pitch class before type overrides, voicing and transpose. Choose another tonic by moving both the input and output names by the same interval. The repeated octave uses the same rule. Here sus4 describes the chord; Orchid writes it as sus.

Physical pitch	C Major result	A natural Minor result
C	CM	CM
C#	Csus4	Csus4
D	Dm	Dm
D#	Dsus4	Dsus4
E	Em	Em
F	FM	FM
F#	Gsus4	Gsus4
G	GM	GM
G#	Gsus4	Gsus4
A	Am	Am
A#	Asus4	Asus4
B	Bdim	Bdim

C Major and A natural Minor share their scale notes and default chords. For other choices, the code’s relative-pitch table is recorded in key_mode_playing.pitch_map in the JSON. A chromatic pitch shifts down a semitone, except Major’s raised fourth and Minor’s raised sixth, which shift up. A held or locked type changes the chord type but keeps this root shift: C# with MIN in C Major gives Cm. Extensions add their fixed intervals to the resolved root and can leave the scale. Secret Chords and Play Style retain their normal modifier behavior. Type and extension handling, modifier changes.

Key plays set to Notes bypasses that chord map. In-scale pitches pass through; outside-scale pitches are silent with Snap Off or move to the nearest Snap target, preferring down on a tie. Scale targets scale notes; Chord targets sounding chord tones and falls back to the scale. On Chords keyboard, type modifiers can still harmonize a pitch that passes this filter. With Full K Shorts Off, Full keyboard ignores retained modifiers; the optional G5 switch below can make it use them. Split Bass keeps its bass-side keys as notes; Notes filtering still applies before the split. Notes and split rules, Snap.

These playing rules also apply in the performance, FX, engine picker, LOCK, Options, sound editor, KEY-play, PLAY-play and save-choice screens. Strum, Slop, Arp, Pattern and Harp arrange the resolved chord. Recording, Step entry and the loop editor capture that resolved root, type and extensions, so Key Mode applies while entering a gesture; saved loop events retain their stored chord when Key Mode changes. Performance, capture hook, loop replay.

The screen writes plain major triads as DM, FM and GM in both naming styles; D by itself means a single note. The guide’s Key Mode examples omit the M on F and G, but the naming code adds it. Extended chords use names such as D7 or DM7. Standard names, Orchid names.

Choose Classic or FM-1 chord keys

Tap GLO, choose Chord Keys with SELECT and turn KNOB 1. Classic is the default with fresh settings, when upgrading settings last written by 0.23 or a pre-layout beta, and after Reset Settings; an ordinary reinstall keeps a layout already saved by 0.24. Classic keeps the earlier key map. FM-1 uses the map below when chord keys are active; Full keyboard and picker pages have their own rules. Changing layouts releases held keys while keeping the LOCK latch; release any physical keys still down before playing them again.

Key in FM-1	Job
F3	Selects 6, which sounds only when a type or enabled Key Mode Chords supplies a chord.
F#3	DIM; by itself it acts immediately when Secret Chords does not apply.
G3	Selects m7, subject to the same chord requirement.
G#3	MIN alone, or SUS when combined with A#3.
A3	Selects M7, subject to the same chord requirement.
A#3	MAJ alone, or SUS when combined with G#3.
B3	Selects 9, subject to the same chord requirement.
C4, C#4	Added roots, using the same Key Mode, modifier, octave and split rules as D4–G5.
D4, D#4, E4, F4, F#4, G4, G#4, A4, A#4, B4, C5, C#5, D5, D#5, E5, F5, F#5, G5	Retain their ordinary root-playing jobs, with the type-window timing below.

Options > SUS Window appears only with FM-1 selected. KNOB 1 sets 30–80 ms in 5 ms steps; the default is 30 ms. A root pressed while a type combination is undecided waits and sounds once after the decision. If released meanwhile, it sounds briefly after that decision. A root already pressed before any type key follows the usual Play Style rules; in Simple it keeps its original note or chord.

G#3+A#3 supplies SUS regardless of Secret Chords. When Secret Chords applies, F#3+G#3 makes minor add-four, F#3+A#3 augmented, and all three make a root-and-fifth chord. A pair waits for the window when a third key could still change its result; all three settle it immediately. Without Secret Chords, the latest type press wins except that G#3+A#3 combines as SUS. Releasing one type does not restrike the chord; the remaining held type applies to the next root. LOCK retains a completed type set, and repeating that set alone clears it on final release while retaining its extensions. Choosing a different type set with no extension key held replaces the latched type; Type key Clears (the default) also removes its latched extensions, while Keeps retains them.

FM-1 layout active: do this	What happens
Tap LFO outside the sound editor	Toggles LOCK on release before the chosen Hold Time.
Hold LFO alone outside the sound editor	Opens or closes the LOCK layer after Hold Time; its controls remain Type key and Ext keys.
Press a key while LFO is down before its layer opens	Toggles LOCK at that key press.
Hold GLO, then tap LFO	Toggles LATCH or first turns off an active performance Hold.
Hold LFO, then tap GLO	Opens the LOCK layer.
Use LFO inside the sound editor	Keeps the editor’s LFO-section job.
Pick a scale in the KEY layer	G#3 chooses Minor and A#3 Major; the second of a close held pair is ignored.
Pick a tonic with both scale keys held	MIN takes priority.
Use C4/C#4 in a picker or naming map	Does nothing; tonic, loop slots and letters still begin at D4.

FM-1 layout active: LFO shows LOCK steadily in Glow. LATCH or performance Hold gives it a 300 ms-per-phase pulse; with LOCK also on it alternates bright and middle levels. An open LOCK layer blinks instead. SUS lights both G#3 and A#3; B3 follows the ninth extension. Stock retains its activity inversion. Loops store resolved chords, so switching layouts does not rearrange a saved loop.

Full keyboard shortcuts

Full K Shorts starts Off. Turn it On in Options to reserve F#5/G5 while Keyboard is Full. In screens where keys play, F3–F5 supply the 25 musical pitches. F#5 and G5 remain switches even on picker and naming pages, except KEY Pick, where they keep their tonic-selection jobs. Other keys retain the active picker or naming map.

Do this	What happens
Tap F#5	Reverses whether the chosen layout’s low chord keys are restored, without playing a note.
Tap G5	Reverses the Full keyboard’s chord switch without playing a note.
Hold either switch for the selected 300–600 ms Hold Time or longer	Reverses its state while down and restores the previous state on release, including temporarily turning an already-on switch off.
Play with chord keys hidden and G5 Off	Plays single notes, keeping Notes filtering, Snap and bass split rules.
Play with chord keys hidden and G5 On	Uses a locked type and extensions, or Key Mode’s chord when it supplies one, otherwise a single note; Notes filtering and bass split still apply.
Restore chord keys with F#5	Returns the chosen Classic or FM-1 modifier map and its normal Key Mode rules, with roots ending at F5; G5 does not suppress those chords.
Choose Keyboard again on KEY page 2	Resets F#5 to hidden and G5 On only when Key Mode is enabled with Key plays Chords.

The switch lights are bright when enabled and faint when disabled in Glow, except during KEY Pick. KNOB 1 changes voicing on Full keyboard too; OCT- and OCT+ set its octave. Shortcut switch states are temporary, while the Full K Shorts preference saves automatically.

With dynamic Key Touch, playable roots sense velocity, including C4/C#4 in FM-1; Full keyboard also makes the remaining low keys musical. Aftertouch is available from F3 through C5; the top seven keys supply velocity only. Fixed touch uses the Velocity option instead.

Do this	What happens
Turn SELECT (home)	Sets tempo from 20 to 300 BPM.
Turn SELECT (full keyboard)	Sets tempo from 20 to 300 BPM.
Turn PRESETS (home)	Loads another chord sound from the current engine, wrapping at the ends and honoring the favorites filter.
Turn PRESETS (full keyboard)	Loads another chord sound from the current engine, wrapping at the ends and honoring the favorites filter.
Turn ALGORITHM (home)	Moves through bass off and the current engine’s sounds, wrapping at the ends and honoring the favorites filter.
Turn ALGORITHM (full keyboard)	Moves through bass off and the current engine’s sounds, wrapping at the ends and honoring the favorites filter.
Turn KNOB 1 (home)	Moves the chord voicing up or down by an inversion.
Turn KNOB 1 (full keyboard)	Moves the chord voicing up or down by an inversion, including the Full keyboard; octave shift stays on OCT- and OCT+.
Turn KNOB 2 (home)	Moves the bass register by octaves.
Turn KNOB 2 (full keyboard)	Moves the bass register by octaves.
Turn KNOB 3 (home)	Changes Strum or Harp rate, Slop amount, Arp division or Pattern number for the selected performance mode.
Turn KNOB 3 (full keyboard)	Changes Strum or Harp rate, Slop amount, Arp division or Pattern number for the selected performance mode.
Turn KNOB 4 (home)	Sets the chord send into the selected effect and turns FX on.
Turn KNOB 4 (full keyboard)	Sets the chord send into the selected effect and turns FX on.

Record and edit a loop

PLAY menu

Do this	What happens
Tap EDIT	Opens the loop editor.
Tap GLO	Switches the PLAY menu’s keys between loop slots and musical playing.
Keep PLAY held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.
Tap SEQ	Closes the PLAY menu.
Tap D4	Chooses loop slot 1 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap D#4	Arms clearing the loop while this key remains held.
Keep D#4 held	After one second held in the PLAY slot menu, clears the loop in memory, with global SAVE or a later slot switch deleting its stored record and revert restoring it until that write.
Tap E4	Chooses loop slot 2 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap F4	Chooses loop slot 3 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap F#4	Cancels an armed or active overdub, or removes the last added layer from memory, without redo, a slot change or an immediate flash write.
Tap G4	Chooses loop slot 4 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap G#4, A#4, C#5, D#5, F#5, G5	Does nothing in this menu.
Tap A4	Chooses loop slot 5 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap B4	Chooses loop slot 6 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap C5	Chooses loop slot 7 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap D5	Chooses loop slot 8 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap E5	Chooses loop slot 9 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Tap F5	Chooses loop slot 10 at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.

PLAY keys play

Do this	What happens
Tap EDIT	Opens the loop editor.
Tap GLO	Returns the PLAY menu’s keys to loop slot selection.
Tap SEQ	Closes the PLAY menu.

Loop editor

Do this	What happens
Keep EDIT held	Closes the loop editor after the chosen 300–600 ms hold time alone.
Tap EDIT	Closes the loop editor to reveal the PLAY menu.
Tap GLO	Leaves the loop editor’s keys playing music without changing their role.
Keep PLAY held	Closes the loop editor after the chosen 300–600 ms hold time, keeping the PLAY menu open.
Tap REC	Deletes the notes starting in the selected step.
Tap SEQ	Closes the loop editor to reveal the PLAY menu.
Keep SEQ held	Closes the loop editor after the chosen 300–600 ms hold time alone.
Tap HOME	Closes the loop editor and PLAY menu, returning to the home view.
Tap OCT-	Moves the octave for notes entered in the loop editor down within the range −2 to +2.
Tap OCT+	Moves the octave for notes entered in the loop editor up within the range −2 to +2.
Tap F3, F#3, G3, G#3, A3, A#3, B3, C4, C#4	With Full K Shorts off, with Full keyboard selected, plays this pitch using Key Mode’s chord or Notes rules and the split settings for the selected loop step, with the gesture written when released.
Tap a root key	Plays this pitch under Home’s Key Mode, modifier and split rules and starts a gesture for the selected step without moving the cursor.
Release a root key	Writes the played gesture into the selected step, replacing its chord or bass side on the first completed gesture of a push.

Step entry

Do this	What happens
Tap PLAY	Commits step entry and starts the resulting loop.
Tap REC	Starts step entry at the first sixteenth, or commits the current step-entry pass.
Tap OCT-	Moves the step-entry cursor back one sixteenth on release, wrapping only when a fixed length is selected.
Tap OCT+	Advances the step-entry cursor by one sixteenth on release, allowing a rest.
Tap a root key	Plays this pitch under Home’s Key Mode, modifier and split rules for step entry, moving to the next step if the previous chord was already entered.
Release a root key	Advances the step cursor once every key and locked modifier is released after an entered chord.

Overwrite recording

Do this	What happens
Tap REC	Starts a replacement take after arming or count-in, keeping the old loop until capture starts.

Advance recording

Do this	What happens
Tap REC	When the current loop is nonempty, stops playback, writes any changed departing loop to its slot, then advances and starts an overwrite take, so revert cannot restore the previous take in the slot just written.

Overdub recording

Do this	What happens
Tap REC	Starts playback if needed and arms an added layer over the existing loop.

Replace recording

Do this	What happens
Tap REC	Arms a layer that replaces the old material where new notes are played.

PLAY page 1

Do this	What happens
Turn SELECT	Chooses page 1 counterclockwise or page 2 clockwise.
Turn PRESETS	Chooses a loop slot at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Turn ALGORITHM	Chooses Overwrite, Advance, Overdub, Replace or Step recording.
Turn KNOB 1	Chooses Free or 1, 2, 4, 8 or 16 bars for the next take.
Turn KNOB 2	Chooses loop rate from x1/16 through x4, applying playing changes at the loop start.
Turn KNOB 3	Chooses recording quantization except Step mode, which stays at sixteenths.
Turn KNOB 4	Switches count-in off or on.

PLAY page 2

Do this	What happens
Turn SELECT	Chooses page 1 counterclockwise or page 2 clockwise.
Turn PRESETS	Chooses a loop slot at the next loop boundary if playing, writes departing changes now if stopped or stages them until a stop, later switch, global save or revert if playing, and loses unwritten changes on power-off.
Turn ALGORITHM	Chooses Overwrite, Advance, Overdub, Replace or Step recording.
Turn KNOB 1	Sets loop level from 0 to 100 in steps of five.
Turn KNOB 2	Switches the metronome off or on.
Turn KNOB 3	Does nothing on PLAY page 2.
Turn KNOB 4	Does nothing on PLAY page 2.

Loop editor 1

Do this	What happens
Turn SELECT	Chooses page 1 counterclockwise or page 2 clockwise.
Turn PRESETS	Moves the step cursor and auditions notes when stopped.
Hold GLO, turn PRESETS	Moves the cursor eight steps per detent.
Turn ALGORITHM	Sets the selected step’s voicing.
Hold GLO, turn ALGORITHM	Snaps step voicing between Follow and zero rotation.
Turn KNOB 1	Sets selected-step note length without moving other steps.
Turn KNOB 2	Sets loop length in sixteenth-note steps.
Hold GLO, turn KNOB 2	Snaps length to 8, 16, 32, 48 or 64 steps in 4/4, or 12, 24, 36 or 48 in 3/4 and 6/8.
Turn KNOB 3	Sets the selected step’s playback chance.
Turn KNOB 4	Sets selected-step note velocity.

Loop editor 2

Do this	What happens
Turn SELECT	Chooses page 1 counterclockwise or page 2 clockwise.
Turn PRESETS	Moves the step cursor and auditions notes when stopped.
Hold GLO, turn PRESETS	Moves the cursor eight steps per detent.
Turn ALGORITHM	Sets the selected step’s voicing.
Hold GLO, turn ALGORITHM	Snaps step voicing between Follow and zero rotation.
Turn KNOB 1	Chooses no ratchet or two, three or four hits.
Turn KNOB 2	Chooses the step’s cycle condition.
Turn KNOB 3	Sets the selected step’s voicing.
Hold GLO, turn KNOB 3	Snaps step voicing between Follow and zero rotation.
Turn KNOB 4	Transposes selected-step notes by semitones, refusing a turn beyond MIDI note range.

Switching from your firmware

Pick the firmware on your FM-1 now to see what installing ChoralRoot does to its data.

1 · Back up first, on Stock V15

Stock V15 has no way to back up your voices or patterns. The FM-1 only sends notes over MIDI, never voice data.
One indirect way to back up, from Baud Girl's own docs (not tested by us): installing her FM-1+VA keeps your saved stock presets and patterns, and its browser Device Manager can then save all 128 presets and 16 patterns as files. FM-1+VA is closed source; install it at your own risk.

2 · What happens to your Stock V15 data

Possibly at risk

(the layout is reported or inferred, not read in code)

stock settings (and possibly patterns)

(weakest evidence: reported)

Everything about leaving Stock V15

Everything else on ChoralRoot

Open layers and use shared gestures

Holding a layer button opens its menu and keeps it open after release. Using another control during the hold can open it immediately. HOME or OCT- leaves a layer; the rows below name exceptions and confirmations.

Do this	What happens
Tap SEL	Toggles Key Mode when SEL is tapped and released without another control being used.
Keep SEL held	Opens the KEY menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold SEL	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Tap ARP	Toggles performance processing when ARP is tapped and released.
Keep ARP held	Opens the PERF menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold ARP	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Tap FX	Toggles the effects when FX is tapped and released outside the sound editor.
Keep FX held	Opens the FX menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold FX	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Tap ENV	Toggles the bass part outside the sound editor, restoring its selected sound if it was off.
Keep ENV held	Opens the BASS menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold ENV	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Tap LFO	In the Classic layout, toggles Latch outside the sound editor, or first disables the current performance mode’s active Hold.
Tap EDIT	Opens or closes the chord sound editor outside the PLAY menu and engine picker.
Keep EDIT held	Opens the engine menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold EDIT	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Hold ENV, tap EDIT	Opens the bass sound editor.
Tap GLO	A quick tap opens or closes Options outside the KEY layer, PLAY menu and sound editor, while holding it alone leaves Options closed.
Hold GLO	Provides alternate knob actions while held without opening Options on release.
Release GLO	Loads the engine selected by the held GLO plus PRESETS or ALGORITHM gesture.
Tap SAVE	Opens the chord sound’s save menu, or the edited part’s menu from the sound editor, except that SAFE MODE refuses to open this save menu.
Keep SAVE held	After the chosen 300–600 ms hold time alone, saves settings, session and changed loops or defers until stop, with SAFE MODE refusing and a restored settings backup requiring a restart first.
Hold ENV, tap SAVE	Opens the bass sound’s save menu, except that SAFE MODE refuses to open this save menu.
Use SAVE + GLO	Holding GLO and SAVE for one second reloads the saved setup and loop without a question, except in SAFE MODE or after a settings restore awaiting restart.
Tap PLAY	Starts or stops the loop outside the sound editor, committing an active take or cancelling its count-in.
Keep PLAY held	Opens the PLAY menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold PLAY	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Tap REC	Starts or ends capture in the selected record mode outside the sound and loop editors.
Hold GLO, tap REC	Cycles Overwrite, Advance, Overdub, Replace and Step for the next recording outside the sound editor.
Keep REC held	Undoes the latest looper layer after the chosen 300–600 ms hold time alone outside the sound editor.
Tap REC	During a take, ends and commits capture; before capture starts, cancels the armed take or count-in.
Keep SEQ held	Opens the metronome menu after the chosen 300–600 ms hold time outside the sound editor, keeping it open after release.
Hold SEQ	Opens its menu immediately when another key, knob or button is used during the hold, except for the sound editor’s own section buttons.
Hold GLO, tap SEQ	Toggles the metronome outside the sound editor.
Tap SEQ	Opens the loop editor unless a take or pending slot switch prevents it.
Tap SEQ	Has no tap action in other layers, Options or sound naming, while the sound editor uses it for modulation.
Tap HOME	Steps through Chord, Keyboard, Notes, Geek Out, Scope and Geek Out 2 on release unless the view is locked.
Tap HOME	Closes a menu or page on release, returning to the sound editor when a layer covered it.
Keep HOME held	Opens the view menu after 600 ms alone, except during sound naming.
Hold HOME + OCT- + OCT+ together for 5 s	Hold HOME, OCT- and OCT+ together for five seconds to enter update mode or USB boot, with a countdown after two seconds and only automatic settings and favorites eligible to save if neither playback nor a pending restore blocks writes, while session edits and changed loops remain unsaved.
Tap OCT-	Moves the playing octave down on release within the range −2 to +2.
Tap OCT-	Closes an open layer on release, except the engine picker, loop editor and active step entry.
Use OCT- + OCT+	Stops notes and transport, drops a fresh take or step-entry notes, keeps a partial overdub, clears Latch and the latched chord while leaving LOCK enabled, and resets octave shift.
Tap OCT+	Moves the playing octave up on release within the range −2 to +2.
Tap OCT+	Closes an open layer on release, except the engine picker, loop editor and active step entry.

Choose a key, bass, performance and effects

KEY layer

Do this	What happens
Keep SEL held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.
Tap GLO	Switches the KEY menu’s keys between selecting the key and playing music.
Tap F3, F#3, G3, A3, C4, C#4	Does nothing while the KEY menu’s keys are set to Pick.
Tap G#3	In Classic, selects the minor scale without sounding a chord.
Tap A#3	In Classic, selects the major scale without sounding a chord.
Tap B3	In the Classic layout, toggles chord-key locking on release in the chord keyboard layout, while Full keyboard leaves B3 inactive in Pick mode.
Tap D4, D5	Sets the key’s tonic to D and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap D4, D5	Sets D as the tonic and selects the minor scale.
Hold A#3, tap D4, D5	Sets D as the tonic and selects the major scale unless MIN is also held.
Tap D#4, D#5	Sets the key’s tonic to D♯ and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap D#4, D#5	Sets D♯ as the tonic and selects the minor scale.
Hold A#3, tap D#4, D#5	Sets D♯ as the tonic and selects the major scale unless MIN is also held.
Tap E4, E5	Sets the key’s tonic to E and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap E4, E5	Sets E as the tonic and selects the minor scale.
Hold A#3, tap E4, E5	Sets E as the tonic and selects the major scale unless MIN is also held.
Tap F4, F5	Sets the key’s tonic to F and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap F4, F5	Sets F as the tonic and selects the minor scale.
Hold A#3, tap F4, F5	Sets F as the tonic and selects the major scale unless MIN is also held.
Tap F#4, F#5	Sets the key’s tonic to F♯ and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap F#4, F#5	Sets F♯ as the tonic and selects the minor scale.
Hold A#3, tap F#4, F#5	Sets F♯ as the tonic and selects the major scale unless MIN is also held.
Tap G4, G5	Sets the key’s tonic to G and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap G4, G5	Sets G as the tonic and selects the minor scale.
Hold A#3, tap G4, G5	Sets G as the tonic and selects the major scale unless MIN is also held.
Tap G#4	Sets the key’s tonic to G♯ and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap G#4	Sets G♯ as the tonic and selects the minor scale.
Hold A#3, tap G#4	Sets G♯ as the tonic and selects the major scale unless MIN is also held.
Tap A4	Sets the key’s tonic to A and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap A4	Sets A as the tonic and selects the minor scale.
Hold A#3, tap A4	Sets A as the tonic and selects the major scale unless MIN is also held.
Tap A#4	Sets the key’s tonic to A♯ and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap A#4	Sets A♯ as the tonic and selects the minor scale.
Hold A#3, tap A#4	Sets A♯ as the tonic and selects the major scale unless MIN is also held.
Tap B4	Sets the key’s tonic to B and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap B4	Sets B as the tonic and selects the minor scale.
Hold A#3, tap B4	Sets B as the tonic and selects the major scale unless MIN is also held.
Tap C5	Sets the key’s tonic to C and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap C5	Sets C as the tonic and selects the minor scale.
Hold A#3, tap C5	Sets C as the tonic and selects the major scale unless MIN is also held.
Tap C#5	Sets the key’s tonic to C♯ and enables Key Mode, retaining the scale unless MIN or MAJ is held.
Hold G#3, tap C#5	Sets C♯ as the tonic and selects the minor scale.
Hold A#3, tap C#5	Sets C♯ as the tonic and selects the major scale unless MIN is also held.

Performance

Do this	What happens
Keep ARP held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.

FX layer

Do this	What happens
Keep FX held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.

Bass layer

Do this	What happens
Keep ENV held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.
Tap D4	Selects Chords Only as the bass behavior.
Tap D#4, F#4, G#4, A4, A#4, B4, C5, C#5, D5, D#5, E5, F5, F#5, G5	Has no key-selection action in the bass menu.
Tap E4	Selects Unison Bass as the bass behavior.
Tap F4	Selects Bass Single Notes as the bass behavior.
Tap G4	Selects Solo as the bass behavior.
Turn SELECT	Chooses Chords Only, Unison Bass, Bass Single Notes or Solo.
Turn KNOB 1	Chooses Chords Only, Unison Bass, Bass Single Notes or Solo.
Turn KNOB 2	Moves the bass register by octaves.
Turn KNOB 3	Chooses bass off or another sound without wrapping.
Turn KNOB 4	Sets bass level.

KEY keys play

Do this	What happens
Tap GLO	Returns the KEY menu’s keys to tonic and scale selection.

Metronome

Do this	What happens
Keep SEQ held	Closes this menu after the chosen 300–600 ms hold time if nothing else is touched.
Tap SEQ	Toggles the metronome while its menu is open.
Tap D4	Selects 4/4 as the time signature.
Tap D#4, F#4, G4, G#4, A4, A#4, B4, C5, C#5, D5, D#5, E5, F5, F#5, G5	Has no key-selection action in the metronome menu.
Tap E4	Selects 3/4 as the time signature.
Tap F4	Selects 6/8 as the time signature.
Turn SELECT	Chooses 4/4, 3/4 or 6/8.
Turn KNOB 1	Sets click level from 0 to 100 in steps of five.
Turn KNOB 2	Does nothing in the metronome layer.
Turn KNOB 3	Does nothing in the metronome layer.
Turn KNOB 4	Does nothing in the metronome layer.

View menu

Do this	What happens
Keep HOME held	Closes the view menu after 600 ms alone.
Tap D4	Selects the Chord view.
Tap D#4, F#4, G#4, A#4, C#5, D5, D#5, E5, F5, F#5, G5	Has no key-selection action in the view menu.
Tap E4	Selects the Keyboard view.
Tap F4	Selects the Notes view.
Tap G4	Selects the Geek Out view.
Tap A4	Selects the Scope view.
Tap B4	Selects the Geek Out 2 view.
Tap C5	Toggles the view lock.
Turn SELECT	Chooses Chord, Keyboard, Notes, Geek Out, Scope or Geek Out 2.
Turn KNOB 1	Switches view lock off counterclockwise or on clockwise.
Turn KNOB 2	Does nothing in the View menu.
Turn KNOB 3	Does nothing in the View menu.
Turn KNOB 4	Does nothing in the View menu.

LOCK layer

Do this	What happens
Tap D4, E4, F4, G4, A4, B4, C5, D5, E5, F5, G5	Plays the pressed pitch at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap D#4	Plays D♯4 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap F#4	Plays F♯4 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap G#4	Plays G♯4 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap A#4	Plays A♯4 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap C#5	Plays C♯5 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap D#5	Plays D♯5 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Tap F#5	When not reserved as a Full keyboard shortcut, plays F♯5 at the current octave as Key Mode’s scale chord or neighboring sus4 with held or locked type overrides and extensions, or follows Notes filtering and Snap, or plays its note or modifier chord with Key Mode off, respecting split settings.
Turn SELECT	Sets tempo from 20 to 300 BPM.
Turn KNOB 1	Chooses whether type keys clear or keep locked extensions.
Turn KNOB 2	Chooses extension keys that toggle or replace their set when pushed.
Turn KNOB 3	Does nothing in the LOCK layer.
Turn KNOB 4	Does nothing in the LOCK layer.

KEY page 1

Do this	What happens
Turn SELECT	Chooses page 1 counterclockwise or page 2 clockwise.
Turn KNOB 1	Chooses a tonic and enables Key Mode.
Turn KNOB 2	Chooses Major counterclockwise or Minor clockwise.
Turn KNOB 3	Transposes future playing from -24 to +24 semitones.
Hold GLO, turn KNOB 3	Transposes in octaves within -24 to +24 semitones.
Turn KNOB 4	Chooses Full Octave, Split Oct or Split Bass.