Getting SHRUB on your FM-1

SHRUB installs from a web page, over the same USB cable you use for MIDI. No drivers, no apps. You need Chrome or Edge on a computer (Safari and Firefox don't have the Web MIDI it uses).

1. Connect the FM-1 to your computer with a USB cable and turn it on.
2. Close the SHRUB editor, M-VAVE's updater and any music software that's using the FM-1.
3. Open shrub.audio/editor/install.
4. Press Use the SHRUB on this site for the latest version, or Choose package (.fwsc)… if you have a file.
5. Press Install and allow MIDI when the browser asks.
6. Leave the cable alone until the installer says it's done, about two minutes. The FM-1 shows SHRUB UPDATE while it's working.

That's it. It restarts into SHRUB, shows the splash and lands on the HOME page.

Updating to a newer SHRUB later is the same thing again. Your user presets and wavetables stay put.

If something goes wrong

• It stopped part way. Don't worry. The FM-1 stays in update mode, even if you turn it off and on. Run the installer again and it carries on where it left off. If nothing had been written yet, it goes back to its old firmware by itself after a minute.
• The installer can't find the FM-1. Close anything else that might be using it (on Windows, only one program at a time can use its MIDI port). Try another cable or USB port.
• It's running some other firmware. The installer knows M-VAVE's own firmware and SHRUB. If yours runs something else and the installer doesn't see it, put M-VAVE's firmware back first, then install SHRUB.
• Nothing works and the screen is dark. Use USB recovery mode: hold OCT− and OCT+ while you turn the FM-1 on, with the cable connected. See Recovery and troubleshooting.

Going back to M-VAVE's firmware

Any time you like. Get the official firmware package from M-VAVE and run their updater as you normally would. The FM-1's boot code is never touched by SHRUB's installer, so the way back always works.

The lay of the land

Seven endless knobs, one volume knob, fourteen buttons, 27 keys and a little screen. Here's what each of them does in SHRUB.

The knobs

The buttons

Each section button opens its section. Press it again to step to the next part of that section. Pills across the top of the screen show that section's parts, with the one you're on lit: always on ENV and LFO, for a moment after each press on EDIT and GLO. You can also hold EDIT, ENV or LFO and turn SELECT to move through the parts either way.

The keys and their lights

The 27 keys play at a fixed velocity of 100 (they don't sense how hard you hit them). Their lights show the notes that are sounding, wherever they come from: your fingers, MIDI, or the arp. On the SCALE page they light up the scale instead. If you play in the dark, KEY LIGHT on the GLOBAL page makes the unlit keys glow faintly.

The screen

Every page is laid out the same way:

• The header: the part's name in its Serum colour, dots for its pages, and the output meter (green to yellow to red, with MASTER's caret on it).
• The display: the part's picture. Wavetables in 3D, envelope and LFO shapes with the playing position moving along them, the filter's curve, the effects doing their thing.
• The deck: four Serum knobs for KNOB 1–4. A knob that's being modulated wears a blue ring showing the range the modulation moves it through.

When you change a stepped value (a wavetable, a filter type, a mode) its name shows up big over the display for a moment.

HOME and presets

HOME is where SHRUB starts and where PRESETS always brings you. It shows the preset's number and its name big, its category as the title (in the category's colour), both oscillators with their wavetables' names, and the effects that are on.

Its four knobs are the ones you'll reach for most: CUTOFF, RES, and both oscillators' wavetable positions, A POS and B POS. The preset's LEVEL is on the GLOBAL page.

The presets

There are 128 preset slots. Slots 1 to 100 hold the factory presets, sorted into seven categories: BASS, LEAD, MISC, PAD, PLUCK, SEQ and SYNTH. Slots 101 to 128 start out as INIT, ready for yours. You can save over a factory slot too; it shows a U in front of its number (U007) once it's yours.

• PRESETS steps through every slot.
• ALGORITHM on HOME jumps to the first preset of the next (or previous) category.
• A MIDI program change picks the slot with that number.

Every preset starts clean: when one loads, SHRUB fades out what's playing (in about 3 ms), clears every effect's tail and the filter, and then brings in the new sound. No thumps, no reverb from the last preset bleeding in.

Favorites

Hold HOME for a moment (about half a second) to make the preset a favorite. Its title gets a star (PAD *). Hold it again to take it off. Once you have favorites, ALGORITHM on HOME also steps through a FAVORITES group, and PRESETS stays among them while you're in it.

"EDITED, TURN AGAIN"

If you've changed the sound and then bump PRESETS, SHRUB doesn't throw your edits away. It says EDITED / TURN AGAIN. Pause a moment and turn again to move on (and lose the edits), or press SAVE to keep them.

Power off, pick up where you left off

SHRUB quietly saves the sound you're working on (and its lanes) a couple of seconds after you stop changing things. Turn it off, turn it on, and you're back where you were. This isn't the same as saving a preset, though: it's just your current sound.

Saving your sounds

Press SAVE. The save page shows the slot it will save into, the name, and what's in that slot now (REPLACES …).

Knobs

SLOT1–128

CURSORor SELECT

LETTERor ALGORITHM

CATEGORY7 of them

Pick a slot, spell the name (up to 16 characters: letters, numbers, space and -+./#&![]), pick a category, then press SAVE again. It says SAVED.

Pressing any other section button leaves without saving.

If the sound has sequencer lanes, the page says SAVE AGAIN: SOUND + LANES, and they're saved with it. The things you might see afterwards:

EDIT: the oscillators, sub, noise and filter

Press EDIT for OSC A, and keep pressing for OSC B, SUB and FILTER. SELECT turns each part's pages.

OSC A and OSC B

Two wavetable oscillators, just like Serum's. ALGORITHM picks the wavetable: 64 built in (Serum 2's, a pack from Serum 1, the tables its factory presets use, and a few rule-based ones), the user tables you load from the editor, and ADDITIVE, a table you build from harmonics.

ALGORITHM: the wavetable. With ADDITIVE chosen, three more pages appear for its harmonics (pick a harmonic and set its level and phase; gain, mode, warp, start, end, curve and frames).

The warp modes are Serum's own: OFF, SYNC, SYNC WIN, SYNC 1/2 WIN, BEND+, BEND−, BEND+/−, PWM, ASYM+, ASYM−, ASYM+/−, FLIP, MIRROR, REMAP 8SQR, REMAP 16SQR, REMAP FLAT, REMAP BLACK, QUANTIZE, PD (B), FM (B), FM (NOISE), FM (SUB), AM (B), AM (NOISE), AM (SUB), RM (B), RM (NOISE), RM (SUB). On OSC B, the "(B)" ones read "(A)".

SUB and NOISE

FILTER

Serum's filters, 76 types of them: the SVFs (LP, HP, BP, PEAK, NOTCH in 6, 12 and 24 dB), Serum 1's MG LOWs, the ladders (MG LADDER, MG DIRTY, ACID LADDER), FRENCH LP, BANDREJECT, ALLPASSES, REVERB, all 32 combs, flangers and phasers, and the dual-filter combos (L+H, L/B/H and friends).

ALGORITHM: the filter type. FAT is whatever the type's second knob is in Serum (Smooth, Pain, Width, Damp, Boeuf, and so on).

ENV: the envelopes

Three Serum envelopes. ENV 1 is each note's volume. ENV 2 is wired to the filter's ENV 2 knob and the matrix, ENV 3 to the matrix only.

Page	Knob 1	Knob 2	Knob 3	Knob 4
1	ATTACK	DECAY	SUSTAIN	RELEASE
2	HOLD	A CURVE	D CURVE	R CURVE

The display draws the envelope with Serum's curves and a dot riding along it for the newest note.

LFO: the LFOs, chaos and the matrix

LFO 1–4

Four LFOs, drawn as Serum draws them, with the playing position moving along the shape. They're shared by all the notes.

ALGORITHM: the mode: FREE (keeps running), RETRIG (restarts with each note) or ENVELOPE (runs once per note, like an envelope).

DEST and AMOUNT are a shortcut into the matrix: they edit the first matrix slot this LFO feeds. Turn DEST on an LFO that goes nowhere yet and SHRUB grabs a free slot for it. With BPM on, RATE steps through 43 note lengths (straight, dotted and triplet).

CHAOS

MATRIX

Sixteen slots, Serum's layout. Each slot takes a source to a destination by an amount. KNOB 1 picks the slot on every page; the other knobs edit it.

The matrix comes last when you press ENV again and again, and last on LFO too, since both are buttons for modulation sources. It's the same matrix from either one.

The sources:

LFO 1LFO 2LFO 3LFO 4ENV 1ENV 2ENV 3CHAOS 1XCHAOS 1YCHAOS 2XCHAOS 2YNOTERANDVELOCITYMOD WHEELAFTERTOUCHBENDMACRO 1MACRO 2MACRO 3MACRO 4

And the destinations are pretty much every knob in SHRUB that turns smoothly: pitches, levels, WT POS, warp, unison, the filter, envelope times, LFO rates and shapes, every effect's main knobs, and the macros' targets.

FX: the effects rack

Serum 1's effects, in a rack of seven slots. The FX RACK page lists the slots; press FX again to step through the effects that are in the rack, in order.

Knobs

SLOT1–7

MODULEwhat's in it

MOVEup or down the rack

ONon or off

The modules: HYPER/DIM, DISTORTION, FLANGER, PHASER, CHORUS, DELAY, COMPRESSOR, REVERB, EQ and FX FILTER. On an effect's own page the rack runs across the top as chips, lit when they're on.

ALGORITHM on an effect's page is its mode, or just on and off. The EQ's bands are LO SHELF, PEAK or HP, and HI SHELF, PEAK or LP.

• DISTORTION: TUBE, SOFT CLIP, HARD CLIP, DIODE 1, DIODE 2, LINEAR FOLD, SINE FOLD, ZERO-SQUARE, DOWNSAMPLE, ASYM, RECTIFY, SINE SHAPER, STOMP BOX, TAPE SAT., SOFT SAT.
• DELAY: NORMAL, PING-PONG, TAP. REVERB: PLATE, HALL.
• COMPRESSOR: on and off. With OTT on it's the famous three-band upward and downward squash; with it off it's a single-band compressor. The display shows each band's level against its thresholds.
• FX FILTER: every voice filter type, after the voices and effects that come before it.

GLO: voicing, global settings and macros

VOICING

SHRUB plays up to four notes at once, each with up to eight unison voices per oscillator, from a pool of 16 voices. A thick unison patch plays fewer notes; one note always plays. MONO keeps the keys you're holding (let go of the top one and it goes back to the one still held). LEGATO doesn't restart the envelopes on a note played over another, and works in poly too.

Page 2 is per-note random: each new note gets its own little nudge of cutoff, tuning, pan and volume. A touch of RAND TUN and RAND VOL goes a long way toward sounding alive.

GLOBAL

• CLICK is the metronome: OFF, ON (while the transport plays) or REC (only while you record; the default).
• Voice control (page 2) is Serum 2's: up to 8 steps, each with its own pan and tune. Every new note takes the next step, round and round. Spread a pad across the stereo field, or detune every other note a hair.
• USB LEVEL: MASTER (USB audio follows the MASTER knob), FIXED (USB audio at full level, MASTER only turns down the jack and speaker), or SPK OFF (USB audio follows MASTER and the speaker and jack go quiet, so you don't hear it twice when monitoring from the computer).
• ARP+SCALE: PRESET (each preset brings its own arp, key, scale and chord) or GLOBAL (they stay as you set them while you change presets, so an arp or a scale you're playing keeps going). Changing them then doesn't count as editing the preset. A preset you save keeps what's set either way.
• MIDI CH, USB LEVEL, KEY LIGHT, BEND RANGE, ARP+SCALE and CLICK are settings of the FM-1, not of the preset: they stay put when you change sounds.

Page 1 also shows a little system status: the CPU load, USB, the second core, the battery (BATTERY nn%) and the firmware version.

Hold GLOBAL for a moment (about half a second) for the shrub: the splash's tree, a new one each time, its leaves lighting up with the sound. Play the keys, or start a sequence, and watch it. While it's up, the four knobs reshape it as you turn them: knob 1 how many times it branches, knob 2 how tall it grows, knob 3 the lit leaves' colors (six sets), and knob 4 how far its branches spread, from a tight column to a wild tangle. Press any button (except PLAY, REC and the octave buttons) or turn SELECT, PRESETS or ALGORITHM to go back.

MACROS

Four macro knobs, MACRO 1–4. On their own they do nothing: they're matrix sources, so route them in the matrix (or drag them onto knobs in the editor) and one knob can move a bunch of things at once. The page lists where each one goes. Factory MIDI CCs 16–19 turn them.

SCL: scales

Knobs

KEY-- (off), C to B

SCALE

CHORDOFF, or a chord

Pick a key and one of Serum 2's 51 scales, and every note snaps into it: the keys, MIDI, the sequencer and the arp. SELECT and ALGORITHM, one above the other, turn the key and the scale too. While you're on this page the keys light up the scale. The scale is saved with the preset.

The scales: Major, Minor and the modes (Dorian, Phrygian, Lydian, Mixolydian, Locrian), the harmonic and melodic minors, pentatonics and blues, a whole world of others (Hirajoshi, Iwato, Klezmer, Persian, Bebop, Whole Tone, Hexatonic…) and Chromatic.

CHORD turns the keyboard into a chord player. The white keys play the scale's steps, with C playing the key's root, and each plays a chord built from the scale's own notes. The black keys pick the chord, from the lowest F#: ROOT (single notes), 3RD, TRIAD, 7TH, 9TH, SUS2, SUS4, 6TH, POWER, OPEN and OCTAVE. While it's on, every key glows, the white keys brighter than the black, and the keys you hold and the chord's black key light up fully. The arp, the sequencer and MIDI out get the chord's notes. CHORD is saved with the preset; with the KEY off the chords are in C.

ARP: the arpeggiator

Serum 2's algorithmic arp. Press ARP to open it and press ARP again to turn it on or off (its light shows which). Hold some notes and go.

Page	Knob 1	Knob 2	Knob 3	Knob 4
1	RATE	GATE1–200%	OCTAVES1–4	CHANCE
2	OFFSET	REPEATS	RETRIG	LATCH

ALGORITHM: the pattern: UP, DOWN, UP/DOWN, DOWN/UP, UP+DOWN, DOWN+UP, THUMB UP, THUMB UD, PINKY UP, PINKY UD, CONVERGE, DIVERGE, CON+DIVERGE, PLAYED, CHORD, RANDOM, RAND NO DUP, RAND DRIFT, RAND ONCE.

• RATE runs from a bar down to 1/64, with dotted and triplet values in between.
• GATE over 100% overlaps the notes, which slides them together in LEGATO.
• CHANCE lets some steps skip. RETRIG restarts the pattern every note, beat, bar or few bars.
• LATCH keeps the arp going after you let go. (This is where the old HOLD went.)

SEQ: the motion sequencer

Eight lanes of motion. Record a knob moving and it plays back on a loop. Record notes and it plays those too.

Recording

1. Press REC. The transport starts if it wasn't already running.
2. Turn a knob. Its moves go into a lane, looping with the lane's length. Stop turning for a moment and that take is done.
3. Play keys while recording and they go into a note lane (one note at a time per lane; up to two note lanes).
4. Press REC again (or PLAY to stop) when you're done.

Editing on the SEQ page

• SELECT picks the lane (1–8). ALGORITHM halves or doubles its length: 1, 2, 4 … up to 128 bars.
• Press SEQ to do what POINT shows: delete the point, clear the lane, or clear everything (that one asks CLEAR ALL? PRESS SEQ AGAIN, so you can't do it by accident).
• Lanes are saved with your preset when you save. Loading a preset that has lanes replaces the ones playing; loading one without lanes leaves yours running, so you can audition sounds under a sequence.
• Between points a smooth knob glides; a stepped one (a type, a mode) jumps.
• The wavetable choice (TABLE) can't go in a lane; switching tables takes too long to do on the beat.

MIDI and USB

SHRUB listens on USB MIDI and the TRS MIDI IN jack, both the same way, on the channel set by MIDI CH (OMNI or 1–16). It understands:

• Notes (with velocity), pitch bend (BEND RANGE sets how far), mod wheel, aftertouch and sustain (CC 64).
• CCs: the factory map below, and you can change it in the editor (right-click a knob for MIDI Learn).
• NRPNs: every automatable parameter has its own, 369 of them. That's how the VST3 and DAWs reach everything.
• Program change: picks the preset slot.
• MIDI clock: start, stop and clock in move SHRUB's transport. Press PLAY on the FM-1 to take the lead back.
• CC 120 and 123 (all notes off) as a panic. CC 121 resets the controllers.

SHRUB sends the notes you play on its keys, and MIDI clock (with start and stop) while its own transport runs. USB also carries SHRUB's audio to your computer (see USB LEVEL on the GLOBAL page).

The factory CC map is in Appendix C.

Appendix A: The moves that aren't on the panel

The cheat sheet. Everything you can do by holding, pressing twice, or doing at power-on.

Appendix B: Recovery and troubleshooting

USB recovery mode

If the FM-1 won't start properly, it can always be rescued. Connect the USB cable, then hold OCT− and OCT+ while you turn it on. It says KEEP HOLDING OCT- AND OCT+ FOR USB RECOVERY; keep holding until it says USB RECOVERY. Now the FM-1's own recovery mode is waiting for the recovery tools (or run the installer again).

SHRUB looks after itself

• A start that keeps failing: if SHRUB crashes soon after turning on, it gets more careful each time. The first time it skips your user presets; the second it does a SAFE START without reading its saved data; the third it goes to USB recovery by itself.
• A hang: a watchdog restarts SHRUB after about 8 seconds. The GLOBAL page then says WATCHDOG RESET, which is handy to mention in a bug report.
• A red screen with a pattern on it is a crash report. It restarts by itself after about 10 seconds. If you can, snap a photo and send it to us.

Little things

• BAT LOW in the title bar means the battery is under 30%. It goes away above 33%. The GLOBAL page shows the percentage.
• Notes stuck? Send all notes off (CC 120 or 123), or use the editor's panic button.
• No sound? Check MASTER, the preset's LEVEL on the GLOBAL page, and USB LEVEL (SPK OFF silences the speaker on purpose).
• The editor says the firmware and editor don't match? One of them is newer. Update the firmware from the installer page, or reload the editor.

Appendix C: The factory MIDI CC map

Out of the box, these CCs turn these knobs. Change it in the editor (MIDI Learn, or File > Load MIDI Map) and the FM-1 remembers your map.

Meet the editor

Every knob of SHRUB on one screen, laid out like Serum 1. It plays SHRUB in your browser, edits your FM-1 live when it's plugged in, and lives in your DAW as the VST3.

• In a browser: open shrub.audio/editor. Chrome or Edge if you want to connect an FM-1 (they have Web MIDI); any modern browser to just play.
• In your DAW: the VST3 has the same editor in its window. See The VST3.

The header

• The tabs: OSC, FX, MATRIX, GLOBAL, SEQ and LIBRARY.
• The preset's name (click it for the list of all presets), with ◀ and ▶ for the previous and next preset.
• File, the menu with everything file-ish (next page).
• ⚠ Panic: all notes off, here and on the FM-1.
• Browser sound: SHRUB playing in your browser. It turns off when you connect an FM-1, so you hear the real thing.
• Feedback: an email to us with the version, the preset and your browser already filled in. Please use it!
• Connect FM-1: connect over USB (more in Connecting to your FM-1).

The File menu

Undo / Redo	⌘/Ctrl-Z and ⌘/Ctrl-Shift-Z, 100 steps, the sound and its lanes together.
Init Preset	Serum's init: a saw on A, dry, quick attack and release.
Open Patch or Serum 1 Preset	A .shrub patch or Serum 1 .fxp presets. Pick several and ◀ ▶ step through them.
Open Serum 1 Folder as a Bank	Every .fxp in a folder, to step through.
Browse Serum 1 Factory Presets	Serum 1's factory presets, ready to play (no Serum needed).
Save to FM-1 User Presets	Into a slot on the FM-1 (when it's connected).
Save Patch to Disk	The sound as a .shrub file, lanes and all.
Export to Serum2	The sound as a Serum 2 .SerumPreset.
User Wavetables	Import WAVs and send them to the FM-1.
MIDI Map	Load, save or reset which CC turns which knob (and in the VST3, save it as the default).
Update FM-1 Firmware	Opens the installer.
About SHRUB	The splash and the credits.

The tabs

• OSC: the sound. SUB and NOISE, OSC A and OSC B, the FILTER, MASTER and VOICING across the top; the macros, ENV 1–3, LFO 1–4 and CHAOS below.
• FX: the effects rack.
• MATRIX: all 16 modulation slots.
• GLOBAL: voice control, per-note random, tempo and level, the FM-1's settings, the ARP and the SCALE.
• SEQ: the motion sequencer's lanes, drawn and edited by hand (in the browser).
• LIBRARY: your FM-1's 128 slots, banks, and Serum 1's factory presets to drag in.

Along the bottom: a keyboard to play (your computer keys play it too, with Z and X for octaves) and the performance sources, NOTE, VELO, RAND, WHEEL, AT and BEND, ready to drag onto knobs.

Connecting to your FM-1

1. Plug the FM-1 in with USB. It has to be running SHRUB.
2. In Chrome or Edge, press Connect FM-1 and allow MIDI when the browser asks.
3. The editor finds the FM-1, says hello, and pulls in the sound it's playing, its lanes, its presets and its MIDI map.

From then on it all goes both ways. Turn a knob in the editor and the FM-1 follows; turn one on the FM-1 and the editor follows. Change presets on either. Browser sound turns off so you're hearing the FM-1 itself, and the editor's keyboard plays it over USB.

How SHRUB makes sound

If you know Serum, this is familiar territory. If you don't, here's the whole trip from a key to your ears.

Two wavetable oscillators (A and B), a sub and noise go into the filter, then ENV 1 shapes each note's volume, then everything goes through the effects rack and out. LFOs, envelopes, chaos, macros and your hands move the knobs along the way, through the matrix.

Oscillators and wavetables

A wavetable is a stack of single-cycle waves (frames). WT POS slides through them, crossfading from one to the next, which is why moving it sounds like a sweep. The OSC tab draws each table in 3D with the playing frame lit up. Then warp bends the wave on the fly (sync, bend, PWM, FM from the other oscillator or the sub, and so on, all Serum's), and unison stacks up to 8 detuned copies, spread by WIDTH and BLEND.

The ADDITIVE table builds a wavetable from 24 harmonics you set by hand, and the RULE tables (RULE 30, RULE 90 and friends) grow frames from cellular automata. Both are tiny, so they save with the preset.

The one filter

This is the big one to know. SHRUB has one filter, shared by every note. Serum gives each voice its own filter; on the FM-1, a filter per voice would eat the CPU we'd rather spend on voices and effects. So the notes are mixed together first, then filtered (that's what "paraphonic" means).

• One note at a time sounds just like Serum. SHRUB even puts ENV 1 after the filter, so a screaming resonance rises and falls with the note.
• Chords share one filter, one cutoff and one ENV 2 sweep. KEY TRK follows the newest note. A resonant filter on a chord rings with the loudest note, not each note on its own.
• When the last note ends the filter is reset, so nothing rings on into the next note.
• The A / B / N / S switches pick what goes through the filter. Anything switched off skips it and joins after, still with ENV 1. Keep the sub out of a resonant filter and your low end stays solid.

Envelopes, LFOs and chaos

ENV 1 is every note's own volume envelope. ENV 2 and ENV 3 are shared: a new note restarts them from where they are and they release when the last key is up. The four LFOs and the two chaos sources are shared too. In Serum terms: think "global" LFOs.

LFOs in the editor are drawn like Serum's:

• Drag the points. Hold Alt to snap them to the grid.
• Double-click the line to add a point, or a point to take it away. Add a fifth point and it becomes a free-drawn shape, up to 17 points.
• Drag the small handle in the middle of a segment to curve it (double-click it to straighten it). For a segment too small for a handle, Alt-drag it.
• Shift-drag paints flat steps, one grid column at a time (Serum's pencil).
• The pencil button beside DEPTH opens a big version of the LFO to draw on.

The matrix and modulation

Sixteen slots. The easy way in: drag a source onto a knob. Grab an ENV, LFO, CHAOS or macro tab (or NOTE, VELO, RAND, WHEEL, AT or BEND along the bottom) and drop it on any knob that lights up. It takes the next free slot at +25%. A modulated knob shows a blue ring for its range.

• Alt-drag a modulated knob to change how much the selected source moves it.
• Click a source to see everything it modulates.
• The MATRIX tab has the full rows: source, amount, destination, bipolar, curve, aux source, invert, aux curve.

The macros (MACRO 1–4) are knobs that only exist to modulate. Drag one onto a few knobs and it moves them all. Its label shows what it's routed to.

Effects

Seven slots, Serum 1's modules: Hyper/Dimension, Distortion, Flanger, Phaser, Chorus, Delay, Compressor (OTT or single band), Reverb (Plate, Hall), EQ and a Filter. Move a module up or down the rack with ▲ and ▼, and grab a starting point from the rack presets (sorted by effect). The DSP is ported straight from Serum's effects, so they sound the way you expect.

Voices, voice control and random

Up to four notes, each with up to 8 unison voices per oscillator, from a pool of 16. Mono, legato and glide work like Serum's. GLOBAL has Serum 2's voice control (each new note steps to its own pan and tune) and per-note random (a little random cutoff, tune, pan and volume per note).

Arp, scale and lanes

The arp (19 patterns, Serum 2's) and the scale (51 scales) are on the GLOBAL tab. The SEQ tab shows the eight lanes the FM-1 records: draw automation and notes, set each lane's length, and export a note lane as a MIDI file (EXPORT MIDI on its head).

SHRUB vs Serum

SHRUB is Serum's DNA on a box with a fraction of a laptop's power. Most of it is the real thing; some of it had to be trimmed.

The same

• The wavetable oscillators, WT POS, the warp modes, unison detune and spread, PAN, PHASE and RAND.
• Serum's filter types (all of Serum 1's and many of Serum 2's), with Serum's cutoff, resonance and drive.
• The envelopes with Serum's curves, LFO shapes and modes, chaos, the matrix with aux and curves, the macros.
• Serum 1's effects, with Serum's algorithms.
• Serum 2's arp patterns, scales and voice control.

Different

• One filter for all notes instead of one per voice (see The one filter).
• Shared modulation: ENV 2, ENV 3, the LFOs and chaos are one for all the notes, not one per voice.
• Four notes at a time, unison up to 8 (Serum: 16), in a 16-voice pool.
• Seven effect slots.
• Noise has no keyboard tracking (its PITCH is fixed), and it's a little quieter than Serum's.

Not in SHRUB (yet, or ever)

• Serum's LFO rise and delay knobs, LFOs 5–8, the porta curve, custom distortion curves.
• Sample and multisample oscillators, granular, the spectral stuff, Serum 2's clips and pattern arp.
• MIDI out of the TRS jack.

New in SHRUB

• Additive and rule-based wavetables, note lanes and the motion sequencer, per-note random, the voice governor that keeps it from glitching, favorites, and an FM-1 that remembers what you were doing.
• An editor and a VST3 that are the same synth, sample for sample.
• Export to Serum 2.

Bringing in Serum 1 presets

SHRUB reads Serum 1 presets (.fxp) and translates them as closely as it can.

• One preset or a few: File > Open Patch or Serum 1 Preset. Choose several to step through them with ◀ ▶.
• A whole folder: File > Open Serum 1 Folder as a Bank.
• Serum 1's factory presets: File > Browse Serum 1 Factory Presets. No Serum install needed; the LIBRARY tab has them too, to drag into slots.

What comes across

• The oscillators, wavetables (by name, from SHRUB's own; a table embedded in the preset comes along as a user table), warps, unison, the sub and noise, the filter (Serum 1's types map one to one), the envelopes, LFOs (drawn shapes too, up to 16 points with their curves), chaos, the matrix with aux and curves, and the first seven effects.
• LFOs 5–8 and chaos S&H are rebuilt on free LFOs when there's room. A one-shot noise hit (the drum trick) becomes ENV 3 on the noise level.

Exporting to Serum 2

Made something on the FM-1 you want in your studio? File > Export to Serum2 (.SerumPreset) writes the sound as a Serum 2 preset, as close to how SHRUB plays it as Serum 2 can get. The wavetables go inside the preset.

1. Load or make the sound (connect the FM-1 to grab the one it's playing).
2. File > Export to Serum2. Save the file.
3. In Serum 2, open it from the preset browser (or drop it in your presets folder).

What doesn't come across, and the editor tells you: the arp, the scale, voice control and per-note random. A few things sound a touch different: Serum 2 filters per voice, so chords through a resonant filter will sound fuller (the opposite of the one filter); some drive and comb filter settings and the noise and sub warps are a little different too.

Your own wavetables

File > User Wavetables opens the tables dialog. Drop in WAV files and they become wavetables you can pick on either oscillator.

• WAV files, made the way Serum makes them: Serum's own exports (they say their frame size), or anything with 2048 samples per frame.
• Up to 64 frames a table. A longer one is thinned to 64 evenly spaced frames.
• Three banks of 16 tables on the FM-1. The dialog shows how much room is left.
• Send them to the FM-1 from the dialog, or with the LIBRARY's Send to FM-1. A preset that uses a user table needs that table on the FM-1, so they travel together.

The LIBRARY and banks

The LIBRARY tab is a map of your FM-1's 128 preset slots, eight rows of sixteen, coloured by category.

• Get from FM-1 pulls in all its slots, user wavetables and MIDI map. Send to FM-1 writes back only what changed.
• Drag slots to reorder them; Alt-drag to copy. Drag presets in from the SHRUB factory list, the Serum 1 factory list, or straight from your desktop (.fxp and .shrub).
• For each slot: rename it, set its category, clear it to INIT, or put the factory preset back.
• The meters show how many slots you've used and how much preset and wavetable memory is left.

Banks

A bank is all 128 slots plus their wavetables (and the MIDI map) in one .shrubbank file. The Bank menu loads the Default Shrub bank and the other factory banks, loads and saves your own, wipes the INIT slots, tidies the wavetables, and sorts the slots by category.

1. Start from the Default Shrub bank, or Get from FM-1.
2. Drag in the sounds you want, rename and categorize them.
3. Save the bank to disk, and Send to FM-1.

Files, at a glance

MIDI mapping

Right-click any knob for MIDI Learn, then wiggle a controller. File > Save MIDI Map keeps your map as a file, Reset MIDI Map goes back to the factory map (Appendix C). Connected, the map is the FM-1's: it remembers it. In the VST3, Save MIDI Map as Default makes every new SHRUB start with it.

The VST3

The same SHRUB in your DAW: the same engine, the same editor, the same presets.

Installing it

Download the zip for your computer from shrub.audio, unzip it, and put Shrub.vst3 in your VST3 folder:

Rescan plug-ins in your DAW and load Shrub as an instrument.

A note on the VST3

While it works as a free VST3 instrument, it isn't really designed as one, though I did spend some extra time so it would be a decent experience. It's 1:1 in sound with the firmware, and it isn't entirely performant: it may look light in your DAW, but Task Manager will tell another tale, because it runs the device's own code. That's on purpose: it's meant to be sound-compatible, and mostly to be an editor and librarian with the convenience of your DAW instead of a web page.

What's the same, what's different

• Everything on the OSC, FX, MATRIX, GLOBAL and LIBRARY tabs works the same. Your DAW saves the whole state with your project: the sound, its wavetables, the library and the MIDI map.
• Automate anything from your DAW (every parameter is there), or play it with MIDI. BEND RANGE is a setting of the plug-in, saved with the project.
• The SEQ tab isn't in the VST3 yet, and the VST3 doesn't connect to the FM-1 or update its firmware: use the browser for those.
• Serum 1's factory presets load even without Serum 1 installed: SHRUB fetches each from shrub.audio the first time and keeps a copy (Xfer Records/Shrub/Serum 1 Presets in your application support folder).

Appendix D: Editor shortcuts

That's everything. Now go make some noise, and tell us what you make.
— Steve and everyone who helped make SHRUB