Manual

Everything the SMK-37 Pro does under Tonitor. New here? Start with Playing it; to install, see Install.

Not a groovebox

No tempo, no steps, no patterns, no drum kit.

Tonitor is for sound heard for itself: texture, grain, movement and slow transformation. You play drones, gestures and textures, layer them, loop them freely out of time with one another, and shape them while they play. It suits acousmatic and electroacoustic work as much as live ambient music, dark ambient above all.

Playing it

Tonitor turns the SMK-37 Pro into six tracks. Each track has its own engine and sound, its own level, pan, filter, granulator, crush and distortion, and its own sends to a master delay and a master reverb. You choose a track on the top row of pads and play it on the keys. The other tracks go on sounding: held notes, latched notes, loops and sequencers keep playing while you choose and play another track.

The tracks start on FM, ANIMA, CALIGULA, HIVE, DRUID and BAYAREA (tracks 1 to 6), with a new sound each, on the OPEN path, in a scale and root drawn at random. Each track has a colour: 1 yellow, 2 cyan, 3 pink, 4 green, 5 orange, 6 lilac.

The panel

This manual calls each control by its Tonitor name. Several buttons carry another word printed on the SMK-37: the button printed SCALE is MACRO in Tonitor, and the button printed FX opens the SCALE page. The table gives both.

The two rows of six buttons glow dimly while idle, so they can be found, and light fully while what they control is on. SHIFT is lit while held. Faders 1 to 3 and the pedal input have no function.

The controls

The keys

All 37 keys play. With a scale chosen, every key, black or white, plays the next step of the scale, up from the root on the lowest key. The keyboard is one continuous run of the scale: a seven-note scale spans a little over five octaves. With CHROMATIC, the keyboard plays as printed, C3 to C6.

Each track's octave 0 places the 37 keys for the scale's length. A twelve-note scale (CHROMATIC) starts at C3. A seven- or eight-note scale starts an octave lower. A five- or six-note scale starts two octaves lower. OCTAVE− and OCTAVE+ move the chosen track from there, as far as every key stays in MIDI's range. A change of scale or root brings each track's octave back into range if it has to.

The keys answer velocity. GLOBAL SETUP's VELOCITY section sets the curve and the range (see Global setup and MIDI). The softest note a key plays is velocity 16, so a light touch is never lost on a sound that answers velocity strongly. A strike slower than 150 ms is taken as one of 60 ms.

Voices come from one pool of twelve shared by all the tracks (CALIGULA and RUSSOLO are one organism a track, outside the pool). A note takes a free voice, so a track has as many as its notes need, and a new note never cuts the release of the one before while voices are free. A key let go ends its note on the track it was played on, so a held note keeps sounding while you choose and play another track. See Voices and load.

Generative paths

Each track has a path that leans what HOME draws, on every engine. A path changes nothing already playing: it shapes the next sounds drawn on that track. Pads 7 and 8 show the chosen track's path.

The engines section gives each engine's families and what the paths do to them. Sessions keep each track's path, and the path each of its sounds was drawn on.

Macros

Press MACRO (lit while on) and the eight knobs stop being the track's mix and effects: they become eight macros that reshape the chosen track's sound while it plays, under a held note. The band under the engine says EDIT in red as long as the macros are on. Press MACRO again to give the knobs back.

Each macro turns from the middle, which is the sound as HOME drew it; either way transforms it. Each answers early in its turn (a quarter of the way gives half the change). While a knob turns, the whole screen is its dial, with the macro's name for this sound, the track and how far it is turned (+40 %, −25 %, AS DRAWN).

The macros are chosen for each engine, and for some by the kind of sound:

Each engine's section below says what its macros do. The mod wheel pushes the first macro up, on top of its knob. Each track keeps the macros of each of its eight sounds. HOME draws a new sound with its macros in the middle. Sessions and presets keep the macros with the sound. MIDI CC 16–19 and 20–23 set macros 1–4 and 5–8.

The macros act only in the track view. On a page (ENVELOPE, DELAY, REVERB, MOD, BALLSY, BRICKLAYER, REACT), the knobs are the page's.

Envelope

Press FADER BANK (lit while the page is up) to open the ENVELOPE page; press it again, or a track pad, to close it. The page shows ENVELOPE and the track's number, the amplitude envelope of the chosen track's sound drawn as a curve, and ATTACK, DECAY, SUSTAIN and RELEASE with their values.

As HOME drew the sound, the page reads the sound's own envelope and says AS DRAWN (in grey): for FM, the envelope of the loudest carrier; for CALIGULA, the average of its pairs' attacks and releases. CALIGULA and RUSSOLO have no decay or sustain stage (shown as 5 ms and 100 %).

The times are on logarithmic scales. K1 and K2 stay the track's level and pan. The value just turned is drawn black on white for a moment.

The first turn starts from the values shown and replaces the sound's own amplitude envelope with the track's: the attack is linear, the decay and release are exponential, the release ending 60 dB down. FM's carrier envelopes and ANIMA's envelope are then held at full; CALIGULA and RUSSOLO are kept playing through the release and then let go. Once the track's envelope is in use, turning the knobs also changes the notes that sound.

HOME (a new sound) or loading a preset gives the sound's own envelope back. Each track keeps an envelope for each of its eight engines. Sessions store them and copying a track copies them; presets do not.

The bottom row of pads

The bottom row of pads (9 to 16) plays no notes. It shows the page of the button that opened it, one page at a time: opening another replaces it. The pages stay up while you choose other tracks; they act on the chosen track.

The same gesture again (or, for LOOP, a second press) frees the pads (PADS FREE).

Chords

With chord mode on for a track, each key plays three notes: its own note and two more of the same scale. Every chord stays in the scale, and its quality (major, minor, diminished) is the scale's at that degree.

Press CHORD to turn the chosen track's chord mode on or off (CHORD lit while on). The screen says the form, or CHORDS OFF. While chord mode is on, CHO shows at the top left of the screen, with the form's abbreviation under it in grey.

Hold CHORD (0.6 s) to put the forms on the bottom row of pads; chord mode comes on with them. Press a pad to choose a form (its name shows on the screen). Hold CHORD again to free the pads. Turning chord mode off, or choosing a track whose chord mode is off, takes the forms off the pads.

One chord sounds at a time on a track: a new key lets the one before go. Chords follow the loops' moves along the scale like single notes, latch with SHIFT (all three notes), are recorded by the loopers as three notes, and apply to BALLSY's and BRICKLAYER's notes as to keys. Sessions keep chord mode, its form and the chords latched; copying a track copies its chord mode.

Latched keys

A latched note sounds on after you let go of its key.

• SHIFT held, then a key: the note latches at once.
• Keys held, then SHIFT: the keys held latch.
• A latched key pressed alone: it is struck again and stays latched. A struck sound that has faded, or a note that was cut, sounds again.
• SHIFT + a latched key: that latch is let go; its note ends as a released key's would.
• SHIFT tapped twice (within 0.35 s): every latched note on every track is let go (LATCH OFF).

Latches belong to the track they were made on. On another track the same keys play as usual, so a drone can be left on one track while you play another. A latched note keeps the velocity it was struck at, also when it is moved along the scale. Latched notes are never taken by a new note and never cut by the load protection (see Voices and load). Sessions keep the latches.

The loopers

Every track has its own looper of up to eight loops, and they are all free: no tempo, no grid, no quantising, not even between a track's own loops. Each overdub is a loop of its own, as long as you made it, going round in its own length over the others, so they drift in and out of phase. Each plays back what was played, to 0.73 ms, with each note's velocity (in 16 steps).

• Press REC to arm a new loop: REC blinks and the band under the engine flashes ARMED and the loop's number in red. Press REC again before playing to disarm it.
• The first note you play starts the recording: REC lights and the band shows REC and the number, white on red.
• Press REC again to end it: the loop is exactly as long as from that first note to this press. It plays at once, round and round (LOOP n). If the track's loops were stopped, they all start again with it.
• Press REC again while it plays to overdub: the same again, a new loop over the others.
• The ninth is refused: the screen says 8 LOOPS.
• REC held (1 s) empties the track's looper, all its loops (LOOP n / EMPTY). Emptying returns the loops to forwards, normal speed and VARY off, and takes away the track's own move along the scale.

A loop can last up to 12.7 minutes; it closes there by itself. A track's loops hold about 500 notes between them. A note still held when REC closes the loop is tied over its end: it sounds on unbroken as the loop goes round, so a drone stays one long note.

The keys go on playing the track over its loops, and the loops' notes and the keys' never cut each other's notes off. The looper records only what is played on the keys (and MIDI in): BALLSY's, BRICKLAYER's and REACT's notes are never recorded.

PLAY stops the chosen track's loops, or plays them again, each from its start. PLAY is lit while they play.

Bringing loops in and out. Hold PLAY (0.6 s; it does not start or stop anything): the chosen track's loops appear on the bottom row of pads, loop 1 (the first one recorded) on pad 9, each overdub on the next. Press a pad to take its loop out (its notes stop, the others go on) or to bring it back in: it comes in at once, from its start. While PLAY is held, the screen shows the loops (in the track's colour: in; a grey frame: out), and the keys from the lowest one up do the same as the pads: the lowest white key loop 1, the next white key loop 2, and so on. The pads stay up after you let go of PLAY; hold PLAY again to free them. With the loops stopped, this chooses which will play: take out all but one, press PLAY, and only that one starts; then bring the others in, one by one. Every loop is in when recorded. Sessions keep which loops are out.

Moving the loops along the scale. Hold SHIFT and press OCTAVE+ or OCTAVE−: every loop of every track moves one step of the chosen scale up or down, so each loop keeps its shape within the scale. Latched notes and the sequencers move with them. The notes sounding move at once, at the velocity they sounded at. The screen shows how far they are moved (TRANSP +2, TRANSP −1, TRANSP 0), up to two octaves of the scale either way. Choosing another scale or root while they are moved walks the new one. The keys move with them: on a track, they play the scale moved as far as that track's loops are, so what you add fits what is there, and an overdub recorded while the loops are moved plays back as you played it. MIDI notes are not moved. Sessions keep the move.

One track along the scale. Hold SHIFT, hold a track's pad, and press OCTAVE+ or OCTAVE−: only that track's loops, latched notes and sequencer move, a step of the scale at a time (TRANSP T3 +2). It adds to the move of all the loops. Holding the track's pad with SHIFT down never copies it. Emptying a track's loops takes its own move away; copying a track takes it along; sessions keep it.

Loop options

Press LOOP to put the chosen track's loop options on the bottom row of pads (LOOP lit; LOOP PADS); press it again to free the pads. Each pad is lit while its option is on and dim while off. The options apply to all the track's loops together, each within its own length.

REVERSE, PENDULUM and RANDOM exclude each other (none lit: forwards), as do HALF and DOUBLE (none lit: normal speed); pressing the lit pad again goes back. CLIMB DOWN and CLIMB UP exclude each other. STUTTER and the climbs are each on or off. All of them combine with the direction and the speed. The climb moves on each time the track's first playing loop comes round; its sounding notes are let go then, and a tied note is struck again.

Changing the direction while a loop plays continues from where it is. An overdub recorded at half or double speed, or while the loops play backwards, is stored so that it plays back as it was played. Sessions keep the options; copying a track copies them. The screen names each change (REVERSE, FORWARD, HALF SPEED, NORMAL SPEED, STUTTER, STUTTER OFF, CLIMB UP, CLIMB OFF).

VARY

SHIFT + REC turns the chosen track's loops' VARY on or off (VARY, VARY OFF; VAR at the top right of the screen while on). Each note the loops play gets a random level (from −10 dB to full) and a random length (50 ms to 1.5 s) instead of the recorded one. Now and then, at odds of its own, a note is changed or joined:

• dropped this time round (5 %);
• late by 5–40 ms (25 %);
• an octave up or down (8 %);
• replaced or joined by a note a step or two of the scale away, or a fifth (8 %);
• preceded by a grace note a step away (4 %);
• struck 2–4 times quickly (4 %);
• joined by a third or fifth above (10 %);
• echoed 1–4 times 120–400 ms apart, each quieter, sometimes climbing or falling a step each time (15 %);
• the notes of a chord strummed 20–60 ms apart (12 %).

Every note stays in the scale. The loops' pace is no longer steady either: it rises and falls slowly, and every few seconds on average it halts for a moment and resumes, bursts to 2–3 times for a moment, grinds to a stop and snaps back, or climbs to 2–2.5 times and drops suddenly (not while REC records). VARY applies to all the track's loops. Sessions keep it; emptying the loops turns it off.

PLAY, the sequencers and the looper

A track has one sequencer at a time: while its BALLSY is on, BRICKLAYER says NOT ALLOWED and changes nothing, and the other way round. The looper works beside either.

A sequencer turned on waits for PLAY. On the sequencer's page, PLAY starts and stops it (PLAY or STOP on the screen), and PLAY blinks while it plays. While the chosen track's sequencer plays, PLAY blinks on every page and stops it from there. When no sequencer of the chosen track plays and its page is down, PLAY is the looper's. So you can put a sequencer's page down, record loops over it from the keys, and start and stop the loops with PLAY. SHIFT + PLAY starts or stops every loop and sequencer of every track together.

The sequencers' notes play as a key's would: in the scale, with the loops' moves along the scale and chord mode. The looper does not record them. REACT, SHADOW and ARP hear them when they play on the guide track.

BALLSY

BALLSY turns on a physics sequencer of bouncing balls for the chosen track and shows its page; BALLSY is lit while it is on and blinks while it plays. Press BALLSY again to turn it off. The balls wait in the middle until PLAY (on their page) starts them; PLAY again holds them still where they are (their notes let go), and PLAY once more moves them on from there. Each track has its own, and they run at the same time.

Hold BALLSY (0.6 s) while it is on to put its page down or up. With the page down the balls keep playing, and the knobs, the screen and the other pages work as usual. A track pad or another page also puts it down.

One to eight balls move in a box on the screen. Each time a ball hits a wall, it plays a note on the track. Each note's length (50 ms to 1.5 s) and level (from −10 dB to full) are drawn at random; the level applies to FM, ANIMA, DRUID, BAYAREA and HIVE (CALIGULA and RUSSOLO play at their own level). Each bounce changes the ball's angle at random by up to 12°, kept between 15° and 75° from the walls, so the paths change and every wall is reached. Each wall holds the notes of the scale, one segment a step, and the segment hit lights up. The pitch rises clockwise all the way round, one octave a wall:

While the page is up, K3–K6 control the balls (K1 and K2 stay level and pan):

The screen shows the box, the walls' segments in the track's colour and the balls; the line above shows the number of balls, or the value just turned. Sessions store each track's balls and whether they are on and playing; copying a track copies them.

BRICKLAYER

BRICKLAYER turns on a step sequencer built a note at a time, for the chosen track, and shows its page; BRICKLAYER is lit while it is on and blinks while it plays. A short press while it is on turns it off (its notes are kept). It waits for PLAY (on its page), which starts it from its first step and, pressed again, stops it (its notes let go). Notes can be entered whether it plays or not. Each track has its own.

Hold BRICKLAYER (0.6 s) to put its options on the bottom row of pads (BRICKS PADS); if it was off, it comes on with them, its page up. Hold it again to free the pads.

On its page, REC is the entry, not the looper:

The notes play in the order they were added, spread over the sequence's length as evenly as possible (a Euclidean rhythm, the first note on the first step: 3 notes in 8 steps fall on steps 1, 4 and 7). Notes are kept as steps of the scale, so they follow the moves along the scale, the scale and the root, as latched notes do. Chord mode applies to them as to keys. Up to 32 notes.

BRICKLAYER's options on pads 9–16 are laid out as the loops' and work the same way on its steps:

With BRICKLAYER's page up, LOOP's pads set BRICKLAYER's options too, all eight: its direction, STUTTER, the climbs and its speed, as BRICKLAYER's own pads do.

The screen shows the steps as cells, eight to a row (up to four rows): a note's cell filled in the track's colour, an empty one as an outline, the step being played in white. The line above shows the notes and the steps (3 IN 8), REC and the number of notes while entering, or the value just turned. Each note lasts 70 % of its step (VARIATION spreads it). Sessions store each track's sequence, settings and options; copying a track copies them.

REACT, SHADOW and ARP

In these three modes the other tracks play along with the one you play. The chosen track is the guide. The tracks you take in listen to everything the guide sounds (its keys, latches, chords, MIDI in, loops, BALLSY and BRICKLAYER) and play their own sounds in answer, in the scale. Choosing another track makes it the guide.

• SHIFT + FADER BANK turns the mode on or off at once (REACT, REACT OFF; SHADOW, SHADOW OFF; ARP, ARP OFF). FADER BANK blinks slowly while it is on, and PLAY flashes with each note the guide plays (keys, chords, loops, BALLSY, BRICKLAYER, MIDI in), on every page but BALLSY's and BRICKLAYER's.
• FADER BANK held (0.6 s) puts its page up, with its pads on the bottom row. Held again while the page is up, both go down. A track pad also puts the page down; the mode goes on running, and its pads stay up.
• On the page, < and > choose the mode: REACT, SHADOW or ARP. Changing the mode lets go of the notes the tracks are playing.
• On the pads, pads 9–14 are tracks 1–6. Press a pad to take that track in or out (2 IN, 2 OUT): lit in the mode's colour while in, dim while out. At first no track is in. The guide's pad is dark; pressed, it lights red for a moment and the screen says GUIDE TRACK (a track cannot follow itself).
• K1 and K2 stay the guide's level and pan. K3–K6 (ARP: K3–K8) set the mode's values, 0–100.

The page shows the mode's name (in its colour while on, grey while off), the name of the knob turned last, its value large, and a bar for each knob. REACT is sea green, SHADOW pale blue, ARP lime.

The tracks taken in play their notes as a sequencer's: the looper does not record them, and they never play on the guide. When the guide stops, they stop. The modes, the tracks taken in and their values are not kept in sessions.

REACT

REACT improvises from a memory of everything the guide plays: its last 128 events (notes or chords), with their levels, lengths and the gaps before them, kept as steps of the scale. After François Pachet's Continuator, IRCAM's OMax and Somax, and George Lewis's Voyager.

Each track taken in improvises from that memory. From the event it played last, it goes on as the guide once went on, or jumps to another place in the memory where the guide played the same intervals (and rhythm), and goes on from there. So its lines are the guide's own, recombined: new phrases in the guide's style, never a pattern of its own. Its rhythm is the guide's, slowed or quickened by its own factor. Each choice is weighed by how it fits the harmony now (what the guide holds, and the pitch classes it played lately), and its notes are moved a third if that fits better. Every note is kept in the scale. When the guide's harmony moves, a long note that no longer fits lets go.

At each of the guide's phrases, and every 6 to 9 seconds of unbroken playing, the tracks regroup. Each takes a way to play, suited to its sound (a texture such as CALIGULA, RUSSOLO, drones and washes plays only slow, low, single notes), and a register of its own:

They start at DENSITY 50, COMPLEXITY 40, CONTINUITY 60, SPREAD 40. After a long silence of the guide, the tracks let go and wait.

SHADOW

The tracks taken in shadow what the guide sounds, each from its own distance behind, at its own pace. Now and then a shadow goes backwards or to and fro, rests and comes in again, its rhythm loosened, moved along the scale.

They start at DELAY 30, DRIFT 30, VARIATION 40, TRANSPOSE 30.

ARP

The tracks taken in break the guide's chord into arpeggios, each at its own pace, its own way and in its own octaves, and follow the chord as it changes. The chord is what the guide holds (a finger lifted, a note less); let go, the last chord goes on until the guide has been silent a while. A single note is arpeggiated over its octaves. A new chord, once it has stood 90 ms, is taken by each track at its next step, from the start of its pattern: never between two of its notes, the pulse unbroken. From silence, the first chord starts them at once. Textures arpeggiate four times slower. The page shows K3–K8 in two rows of three.

They start at RATE 50, RELATION 40, MOTION 40, MUTATE 20, RANGE 30, CHANCE 10.

Copying a track

Hold a track's pad until the screen flashes COPIED / TRACK n: the track is on the clipboard, and its pad blinks. Choose another track and hold its pad until PASTED / TRACK n: it now has the copied track's tone, sequencers and loops. The clipboard is then empty: the next hold copies again. Holding the copied track's own pad again copies it again (as it is now), pasting nothing.

What is copied: the tone (the engine, the sounds of all eight engines with their macros and envelopes, the filter, the granulator, the crush, the distortion, the delay and reverb sends, the octave, the path, the modulation and the chord mode), BALLSY and BRICKLAYER with their settings, and all the loops with their options and VARY, every overdub, those taken out still out. The copy is taken when you hold the pad: what the track does afterwards is not pasted. The track pasted onto keeps its level and pan; whatever it had before is replaced, and its latched notes are let go. The clipboard is kept in the flash beside the sessions (writing it may hush the audio for a moment); it is emptied when the keyboard is switched off.

Gesture loops

Besides its note loops, each track has eight gesture loops: recordings of your hands on the knobs and faders, played back round and round. They have nothing to do with the note loops: they run whatever else plays, held notes, latched chords, loops, sequencers, each at its own length, so they drift against everything else. A filter sweep made over the end of a phrase comes back, next time, over another part of it, and further along each time. That is the point: the gestures are not tied to the notes, and they bring the unexpected, even to you.

Press the sixth button of the top row (GESTURES; lit while it is up): the chosen track's eight gesture loops are on the bottom row of pads, 9 to 16, all glowing faintly sky blue even while empty, so you know the pads are theirs. Press it again to free the pads.

• Hold a pad (0.8 s) to arm it: it blinks red and the band says ARMED. Whatever it held is emptied.
• Move a knob or a fader: the recording starts with that move (the pad turns red; the band says G1 REC). Everything you move after it is kept, as long as you go on.
• Press the pad to end it: the gesture loop is as long as from that first move to this press, and it plays at once, round and round (sky blue).
• Press a recorded pad to switch it off (dim) or back on (lit; it starts from its beginning).
• Press an armed pad before moving anything to let it go (NOT ARMED).

What a gesture loop records: the track's filter (K3), granulator, crush, distortion, delay and reverb sends, level and pan, the eight macros (with MACRO on) of the sound it plays, and faders 2 and 3 (SPACE and the master filter). It records the track you armed it on; switching tracks while it records, the other track's knobs are not recorded, the faders still are. One gesture loop is armed or records at a time: arming another ends the one recording.

What it plays moves those values as your hand would: you can move them between its events, and it takes them over again at its next one. A fader's own position is left where it is until you move it again. All the gesture loops of all the tracks share one store of about a thousand moves; when it is full the screen says GESTURES FULL (empty one by arming it). Sessions keep them; snapshots and copying a track do not (yet).

The wheels and the master

The pitch wheel bends the chosen track up to 2 semitones either way. Every engine bends. The mod wheel adds a vibrato (5.5 Hz, up to 0.4 semitone) and pushes the first macro of the sound up, up to its full turn. Both act on the chosen track only; choosing another track lets go of them on the one left. The wheels calibrate themselves: the pitch wheel's rest is taken at power-on.

Fader 4 (the rightmost) is the master level. It sets what reaches the headphones and the outputs, not the USB audio (see USB audio).

The faders

Faders 1 to 3 are live controls over the whole instrument. They act on top of what is stored and are never saved: sessions, snapshots and presets keep what they kept before, and the faders act on them wherever they stand. While a fader moves, and a moment after, the screen shows its dial.

Fader 1, MORPH. A morph by hand between snapshots. Set the morph time (K3 on the SNAPSHOTS page) to MANUAL, its lowest setting, below OFF. Then a pad on the SNAPSHOTS page no longer recalls its snapshot at once: tapping it makes it the target (its pad and box blink; the screen says FADER 1 UP or FADER 1 DOWN), and nothing changes yet. Move fader 1 from wherever it stands to the end it is furthest from (the top; or, if it stands near the top, the bottom): levels, pans, sends, filters, macros and the other values that glide follow the fader from the snapshot you are on to the target; what has no in-between (scale, root, octaves, loops, latched notes, sequencers, engines) switches at the half-way, in either direction; a track whose sound differs goes down to silence there and comes back. You can go back and forth on the way. At the end the machine is the target exactly, and it becomes the snapshot you are on; the fader then does nothing until you tap another pad. Tapping another pad on the way starts again from whichever of the two the machine is nearer. With any other morph time, a pad recalls as before (at once, or over that time) and fader 1 does nothing (its dial says OFF, K3 TO MANUAL).

Fader 2, SPACE. At the bottom, everything as set. Pushing it up raises every track's reverb and delay sends together, lengthens the reverb's decay and adds repeats to the delay, towards a wash at the top. Pulling it back brings the mix back to dry. The values you set on the DELAY and REVERB pages and each track's sends stay as they are.

Fader 3, the master filter. One filter over the whole mix, after the delay and the reverb, before the master level (and in the USB audio's STEREO too). The middle is off, with a small zone either side so the fader finds it easily. Below, a low-pass comes down from 20 kHz to about 60 Hz; above, a high-pass goes up from 20 Hz to about 8 kHz; a little resonant towards the ends. It glides as the track filter does. Its dial reads LP 1.2K, HP 400 or OFF.

The faders act from where they are at power-on: fader 2 up means SPACE is already on, fader 3 away from the middle means the master filter is already on.

The screen

The screen is made for low vision: few words, very large type, high contrast.

From top to bottom, the track view shows:

• the track number, very large, in the track's colour; at the top left CHO and the chord form while chord mode is on; at the top right the battery (three bars green, two green, one amber, one red when low; a white bolt on a computer's USB power, when the reading is the supply's) and the track's octave to its left (+1, −2; nothing at 0), with VAR under them while the loops VARY;
• the track's engine, in white;
• the family of its sound, in the track's colour. When something changes (NEW, OCT +1, LOOP 2), a black-on-white message replaces it for a moment. While the looper is armed this band flashes ARMED and the loop's number in red; while it records it shows REC and the number, white on red. While MACRO is on it says EDIT in red;
• the track's level meter: a bar filling from the left in the track's colour as it sounds (−48 to +6 dB), and a white mark at the level K1 sets (red at the left when the track is off);
• at the very bottom, the track's pan: a block in its colour on a line from left to right, with a tick at the middle.

K3 to K8 (filter, granulator, crush, distortion, delay send, reverb send) each show, while they turn and for a second after, a full-screen dial: the knob's name and the track, an arc from 7 to 5 o'clock lit in the track's colour, a white pointer, and in large type what it does (LP 1.2 KHZ, DARK 40, BITS 6.5, SEND 40). The macros show the same dial. K1 and K2 say their value in the message band.

Saving, loading, emptying a looper, copying and pasting flash the whole screen for 1.5 s. The pages (SCALE, ENVELOPE, DELAY, REVERB, MOD, SNAPSHOTS, SESSIONS, PRESETS, GLOBAL SETUP, BALLSY, BRICKLAYER, the loops while PLAY is held, REACT) each take the whole screen and are described in their sections. On every page, the value just turned is drawn black on white for a moment.

If the chip's second core did not start, the screen says 1 CORE for a few seconds: the instrument plays, with half the room for voices.

Scales

One scale and root for the whole keyboard, saved with the session. At start, and in a new (empty) session, both are drawn at random. Press SCALE to open the SCALE page: K1 chooses the root (C to B, round the octave), K2 the scale. The page shows SCALE, the root very large, and the scale's name under it; what you just turned is drawn black on white for a moment. SCALE again, or a track pad, goes back.

Hold SCALE (0.8 s) to draw a new scale and root at random, as at start, from any page. The SCALE page shows them for 1.5 s, then the page that was up comes back. The loops and latched notes follow the new scale, as when you turn K1 or K2.

The root sits on the lowest key and the scale climbs from there across all 37 keys, black keys included (see The keys for where each scale starts).

The screen splits the longer names over two lines (MIXO- LYDIAN, HUNGAR- IAN MINOR, OCTA- TONIC, PROME- THEUS, CHROMA- TIC) rather than squeezing the letters together. MIDI notes are not quantised to the scale.

Presets

Each engine has 64 presets, P1 to P64, for the sounds you want to keep and bring back on any track. Hold SHIFT and press SCALE: the PRESETS page of the chosen track's engine opens (the engine's name over the slots), four slots a page. < and > step through them; a slot holding a sound shows its number in red and the sound's family numbered among that engine's presets of the family, in the order of the slots (BRASS 1, BRASS 2, STRINGS 1); an empty one EMPTY in grey. SHIFT + SCALE again, or a track pad, goes back.

• SCALE held (0.8 s), or SAVE held, saves the track's sound into the slot chosen. Over a sound already there it asks OVERWRITE? first, on NO until > turns it to YES (< back to NO); SCALE (or SAVE) answers.
• SCALE pressed, or SAVE pressed, loads the slot chosen into the track (which crossfades to it, as to a new sound) and goes back to playing. An empty slot says EMPTY.

A preset keeps what draws the sound again exactly (its seed, its family, its path and the generation of the generators that drew it), its level and its eight macros. A sound chosen by family (SHIFT + < / >, SHIFT + HOME) comes back the same from a preset or a session. It does not keep the track's envelope: a preset loads with the sound's own. A preset loaded draws the same modulation as HOME would with that sound. Saving erases flash, which silences the audio for a moment.

Snapshots

A snapshot is the state of the machine at one moment. Each session holds 16 of them, one on each pad.

Press SAVE (lit while the page is up): the SNAPSHOTS page opens, 16 boxes in two rows of eight, as the pads. A filled box holds a snapshot; the one last stored or recalled is white. While the page is up, the 16 pads are the snapshots, the top row 1 to 8 and the bottom row 9 to 16: they choose no track and no path. A pad holding a snapshot glows; the one last stored or recalled is lit; an empty pad is dark.

The keys go on playing while the page is up, and K1 and K2 stay the track's level and pan.

What a snapshot holds. The whole state of the machine. For each track: the engine it plays; the sound on every one of its eight engines, each with its eight macros and its envelope; level, pan, reverb and delay sends, filter, granulator, crush, distortion, octave, the track's transposition, its path, chord mode and modulation; its latched notes and chords, with their velocities; BALLSY's and BRICKLAYER's settings (BRICKLAYER's STUTTER and climbs too), BRICKLAYER's notes, and whether each plays; and its loops: which loops there are, where each stood against the others, which are taken out, whether they play, and their direction, speed, VARY, STUTTER and climbs. For the machine: the reverb, the delay, the scale, the root, the loops' transposition and REACT, SHADOW and ARP (on or off, the mode, the tracks taken in, the values on their pages). Not stored: the track chosen, MACRO and which page is up.

For example: record a loop and store snapshot 1; record an overdub and store snapshot 2. Snapshot 1 brings back the loop alone and snapshot 2 brings back both. Loops that are in both snapshots keep playing when you switch; a loop that comes back is placed where it stood against the others when it was stored.

A loop that a snapshot holds stays in memory even after you empty the looper (hold REC). It shares the looper's room with what you record: when the looper has no room left, REC says LOOPER FULL. Snapshots that share sounds, latched notes or loops store them once. If there is no room for a new snapshot, the screen says FULL; empty snapshots you no longer need (SHIFT + hold the pad).

Morph. With a morph time of 0 (OFF), a recalled snapshot is applied at once. With a longer time, the machine moves to it over that time; the snapshot's box and pad blink until it is reached:

• Levels, pans, sends, filter, granulator, crush, distortion, the macros and envelope of a sound that stays, the modulation amounts, LFO rates and fades, the reverb's DECAY, DAMP and MIX, the delay's REPEATS, DAMP and MIX, and the sequencers' speed, rate, harmony and instability change gradually.
• Everything that affects pitch changes at once, halfway through: scale, root, octaves and transpositions. So do the delay's TIME and the reverb's SIZE, the loops, the latched notes, chord mode, the sequencers and their notes, the loops' and BRICKLAYER's STUTTER and climbs, the modulation routings and LFO shapes, and REACT, SHADOW and ARP.
• A track whose sound changes fades out from a quarter of the way, switches sound halfway and fades back in by three quarters.

Recalling another snapshot during a morph starts a new morph from the current state. The morph runs in the main loop and adds no load to the audio.

Snapshots are saved in the flash with the session (hold SAVE, off the SNAPSHOTS page, to save). A new session has none; sessions saved before BUILD 33 load with none.

Sessions

The keyboard always starts with no session loaded. There are 64 slots, numbered 1 to 64.

A session is the whole machine: every track's engine and its eight sounds with their macros and envelopes, its path, octave, level, pan, filter, granulator (and the character it was drawn with), crush, distortion, delay and reverb sends, modulation, chord mode, latched notes, BALLSY, BRICKLAYER, and its loops (playing or stopped, each overdub in or out, with their options and VARY); the scale and root, the moves along the scale, the delay, the reverb, REACT, SHADOW and ARP, the 16 snapshots with the loops they hold, the morph time, and the track chosen. A session stores in full the sound of the engine each track is on, and the others as the seed that made them and their level, so they come back the same.

Choosing and loading. Press SHIFT + SAVE: the SESSIONS page opens, on the session loaded if there is one. < and > step through the slots. The number is very large: red when the slot holds a session, grey with EMPTY under it when it does not; the session loaded says LOADED. Press SAVE:

• on a slot holding a session, it loads (LOADING, then LOADED and the number);
• on an empty slot, it starts a new session there (NEW and the number): a clean slate, as when the keyboard is switched on. The loops and latches go, every track is on its starting engine with new sounds and its settings at their defaults, a scale and root drawn at random, and the delay, the reverb and the moves along the scale too. The session you were in stays saved as it was, and the next save goes to the new slot.

Either way the page closes. A track pad, or SHIFT + SAVE again, closes it without either.

Saving. Hold SAVE (0.8 s):

• with a session loaded or chosen, it saves over it at once (SAVING, then SAVED and the number);
• with none loaded or chosen (just after switching on), the first empty slot is offered (SAVE NEW): < and > choose NO or YES, SAVE answers (NOT SAVED on NO);
• on the SESSIONS page, SAVE held saves into the slot shown, whatever is loaded: the session loaded is saved over at once; an empty slot asks SAVE NEW; another slot holding a session asks OVERWRITE? in red, on NO until > turns it to YES; SAVE answers.

The sessions live in the keyboard's user flash area: 40 sectors of 4 KB, shared with the presets, GLOBAL SETUP and the clipboard. A typical session takes one sector; a session with long loops takes more. When there is no room the screen says FULL. The first save takes over the area where the stock firmware kept its own settings; if you go back to the stock firmware, it rebuilds them.

A session also keeps the seeds its sounds were made from, with the path and the generation of the generators that drew them. Every generation is kept exactly as it was, so sessions and presets saved under an older build load with the same sounds after an update that brings new generators. Erasing flash silences the audio for a moment: a save uses blank flash when there is some, and the keyboard blanks free flash by itself while nothing sounds.

Backing up. The backup page saves them to a file on your computer and puts them back, over USB MIDI: it lists, sends and receives the sessions, the presets and GLOBAL SETUP, each record checked whole before it replaces the one with the same number. As each one arrives, the screen shows RESTORED and its number.

Global setup and MIDI

SHIFT + SAVE held (0.8 s) opens GLOBAL SETUP, the keyboard's own settings, kept apart from the sessions. It has three sections, MIDI, VELOCITY and AUDIO. < and > move through the entries and SAVE goes into one. On a setting, SAVE puts the focus on its value (a white field), < and > change it, and SAVE sets it; SHIFT + SAVE leaves it as it was, or goes back a level, and at the top level closes GLOBAL SETUP. Each level below the top starts with BACK. A track pad also closes it. What changed is written to the flash when you leave.

MIDI in comes over USB only (the SMK-37 has no MIDI IN jack). A note plays every track whose IN channel it is on, and the chosen track on the AUTO channel, at its velocity (the VELOCITY settings apply to the keys only). The CCs a track answers to, on the same channels, and sends when SEND CC is on:

MIDI out goes over USB and out of the TRS jack together: every message sent over USB also goes out of the jack, with or without a computer, while TRS OUT is ON. With SEND NOTES on, each track sends the notes it plays (from the keys, the loops, BALLSY, BRICKLAYER, REACT, SHADOW, ARP and MIDI in) on its OUT channel. With SEND CC on, the values above go out when they change, whatever changed them. Both are OFF at the start: turn them on to drive other instruments. A jack with nothing that answers is left quiet; the keyboard never waits on it. There is no MIDI clock, transport or program change: Tonitor has no tempo or patterns.

Modulation

Each track has a small modulation matrix: two LFOs and four slots that move the track's own values while it plays. The third press of SEQ opens the MOD page, in the track's colour. < and > go through its six entries (LFO 1, LFO 2, then MOD A to MOD D), and K3–K6 set the entry's four rows.

The modulation moves the values the track already has (what the knobs set, or the macros) around where they are, and the whole track follows. It moves a value once a block, so it costs next to nothing. Sessions keep each track's modulation, and copying a track copies it.

SHIFT + SEQ throws the chosen track's modulation anew (MOD RANDOM): both LFOs (any shape, rate, mode and fade) and two to four slots, from any source to any destination, by amounts that may go far. It takes risks on purpose; press it again for another, or set what you like on the MOD page.

HOME draws a modulation with some sounds, by engine and family: mostly with the slow, sustained families of FM, HIVE, BAYAREA and DRUID (a slow LFO on the tone, sometimes a fade in, sometimes a second, slower one in the stereo field or the reverb); now and then a struck or plucked sound gets its brightness on the velocity; never ANIMA or CALIGULA, whose sounds already move by themselves. A new sound with none clears the track's modulation; a preset loaded draws the same modulation again.

The filter and the crush

K3 is the chosen track's filter. From the middle (off), left is a resonant low-pass coming down from 20 kHz to about 35 Hz; right is a resonant high-pass going up from 16 Hz to about 12 kHz. The further from the middle, the more resonant. Its dial reads the mode and cutoff (LP 1.2 KHZ, HP 400 HZ, OFF). The cutoff glides smoothly as you turn, like an analog filter's: each click of the knob moves it about a third of an octave, turned fast two clicks' worth, and the filter slides there over about 25 ms rather than jumping.

K5 is the chosen track's crush. The middle is off. Left takes the bit depth down from 16 to 1.5 bits (the sound coarsens, then breaks up, quiet tails gating out); right takes the sample rate down from 44.1 kHz to about 300 Hz (metallic aliasing, then a stepped buzz). Both follow curves that keep the first half of the way playable; the rate glides, it does not jump. Its dial reads BITS 6.5 or RATE 2.6K. It comes after the granulator, before the track's limiter.

Both are saved with the session.

The granulator

K4 is the chosen track's granulator. The middle is off (as it starts).

• Left, towards dark ambient: long, overlapping, slowly drifting grains (60–400 ms), pitched down now and then, reversed now and then, darkened, fed back on themselves, sometimes frozen (the buffer stops listening for a few seconds and the cloud turns over what it holds).
• Right, towards scattering: short, fast grains (40 ms down to 4 ms, up to about 650 a second), their timing, place, pitch and level jittered more and more, reversed, stuttered, full of holes, decimated at the far end.

The further from the middle, the more grains and the less of the track. Its dial reads DARK 40, SCATTER 25 or OFF.

Each track keeps the last half second of its own sound (at 22.05 kHz, 8-bit μ-law: a little grit is part of it) and plays grains out of it, after its filter. Each track's granulator has a character of its own, drawn at random when the keyboard starts and every time a session is loaded: the intervals its grains are pitched to, how often they reverse, stutter, drop out or freeze, the shape of its scattered grains, how far its feedback and darkening go, how it drifts. The knob's position is saved with the session; the character is drawn anew. When the track's notes end, its grains ring on for about two seconds.

The distortion

K6 is the chosen track's distortion (0–100; 0 is off). It comes after the track's filter, granulator, crush and limiter, and before its level, pan and sends, so the delay and the reverb receive the distorted sound. Its dial reads DISTORTION n and the amount.

• Two gain stages in series: the first symmetric (odd harmonics), the second asymmetric (even harmonics). The amount sets the drive into the first stage (×0.5 to ×32, up to +36 dB) and the second stage's gain and bias.
• A bias in proportion to the input's own level is added before the first stage, so the clipped wave stays asymmetric and keeps its even harmonics at any drive. At low amounts the second harmonic dominates; higher amounts add more harmonics.
• The highs are raised 6 dB before the stages and lowered 6 dB after, so the mids and highs distort more than the bass. The stages run at twice the sample rate to reduce aliasing. A low-pass after them goes from 16 kHz down to 6.5 kHz as the amount goes up.
• The output level is matched to the dry signal's level (measured over about 0.2 s), so turning the amount up changes the drive and the harmonics, not the loudness.

Stored in sessions and copied with the track.

The delay

A master delay, mono, placed before the reverb. Each track's delay send (K7, its dial reading DELAY n / SEND) feeds it; its echoes go to both sides of the master, and half of their level also goes into the reverb, so the echoes are reverberated. Its line holds 2 seconds at 22.05 kHz in 8 bits (μ-law, as the granulator's), so the repeats are slightly dark and grainy.

The first press of SEQ opens the DELAY page: the title and its four values in rows, each with a bar.

The delay's values and every track's send are kept in sessions; copying a track copies its send. The delay costs nothing while nothing goes into it and its tail has died away.

The reverb

A plate after Jon Dattorro (1997): a predelay, input diffusion, and a figure-of-eight tank whose two allpasses sweep slowly out of step, so the tail stays in motion and never rings. Each track sends to it after its level (K8, its dial reading REVERB n / SEND); the reverb's return is added to the mix before the master. The plate runs at 22.05 kHz, half the sample rate, with Dattorro's times and decay kept: its top is near 11 kHz.

The second press of SEQ opens the REVERB page.

The reverb's values are kept in sessions. It costs nothing while nothing goes into it and its tail has died away.

USB audio

Connected to a computer (or a phone or tablet that takes USB audio), the keyboard is also a USB audio input: choose "SMK-37 Tonitor" as the input in the recording program. It carries the master output, stereo, 16-bit, at 44.1 kHz (the rate Tonitor renders at; there is no 48 kHz). It is class compliant: no driver is needed, and MIDI goes on over the same cable. The stream is taken before fader 4, so the fader sets the headphones' level and not the recording's.

TRACKS. In GLOBAL SETUP, AUDIO > USB > OUT chooses what goes out: STEREO, the master as above, or TRACKS, six mono channels, track 1 on channel 1 to track 6 on channel 6, to record the tracks apart. Each track is taken after its level, before its pan and before the master delay and reverb. When you change it, the keyboard leaves the USB for a moment and comes back as the new device (with six channels, or two); the recording program may need to choose it again. The setting is kept, and the keyboard starts as it was left.

Voices and load

The six tracks are rendered a block of 32 samples (0.73 ms) at a time. Every sounding voice takes a share of that block. When the total passes 82 %, Tonitor protects the audio: it ends the quietest fading tails first, then the quietest voices, each faded over a few milliseconds so nothing clicks. A latched note is never ended this way. Below 82 % nothing is cut. What each engine costs, and how much you can stack, is measured in docs/smk37/engine-costs.md.

With all twelve voices busy, a new note takes the release tail that has rung longest (on any track), else the oldest note held on its own track, else the oldest held anywhere, never a latched one.

Every sound ends. Once its key is let go, a voice is faded out over 0.19 s when it has been 66 dB under its loudest for 0.2 s, when it has not fallen 1.5 dB in 2 s, or 30 s after its release began. Held and latched notes are not touched.

Starting, rescue and UBOOT

At power-on the screen shows TONITOR and the build (BUILD 31, for example), then the track view.

RESCUE. Hold OCTAVE− alone while switching the keyboard on: it starts in the rescue mode. The screen shows RESCUE, CONNECT USB, and RUN INSTALL (or UNKNOWN FLASH if it cannot read its flash). Connect it to the computer and run the installer: the rescue mode accepts a new package as the normal mode does. Nothing sounds and nothing is written in this mode until the installer writes. If Tonitor fails to start twice in a row, the keyboard starts in RESCUE by itself.

UBOOT. Hold OCTAVE− and OCTAVE+ together for 5 seconds while Tonitor runs: the audio stops, the screen shows UBOOT in blue, and the chip restarts into its own built-in updater (it appears on USB as WL82 UBOOT1.00). It is a way back whatever happens, and it is how the flash backup tool reads the keyboard (see docs/smk37/backup.md). Switch the keyboard off and on to leave it. Holding both buttons at power-on does not start RESCUE; hold them 5 seconds once Tonitor has started.

The engines

Each track plays one of eight engines, and keeps a sound of each. HOME draws a new sound on the track's engine, leaning to its path; SHIFT + HOME draws one of the same family; SHIFT + < / > draws one of the family before or after. Every sound is drawn from a seed, measured as it is made, and given the gain that brings it to one loudness. What each engine costs on the SMK-37's chip is in docs/smk37/engine-costs.md.

FM — six operators, DX7 style

The classic six-operator FM (msfa, the core of Dexed: 32 algorithms, rate/level envelopes, ratio or fixed frequencies, feedback, LFO, pitch envelope). FM plays from the shared pool of voices and is the lightest of the voiced engines. HOME draws a patch from one of the families of sound objects below.

GLISSE (glissandi: a pitch envelope travelling octaves) and RUBBER (low ratios, the pitch bouncing in at every note) are no longer drawn: WARP took them over, with their weight. A sound saved as a GLISSE or RUBBER under an earlier generation still loads as it was; SHIFT + < / > steps over them.

SHAPER, LADDER, REVERSE, CREEP and CLANG were learned from a collection of 9,606 DX7 voices: the idioms its programmers used that the other families do not make. Each draws one of its family's skeletons (algorithm, feedback, every operator's frequency and level, taken from the collection), an envelope shape for each operator, and the rest within the family's ranges: new sounds of that kind, never one of the collection's voices again.

Each patch is then shaped with care: modulators on high ratios turned down (their sidebands alias and scream), the brightness scaled down the keyboard so high notes are not shrill nor low ones muddy, rate scaling on the carriers. A patch may also be made plucked whatever its family, have a modulator moved to another ratio, or an operator detuned against the rest, and about half the patches are bent once more, gently. HOME draws several patches, measures each, and keeps one whose brightness suits the track's path (darker on AMBIENT, brighter on EXPERIMENTAL), avoiding the family the track had.

On AMBIENT, FM favours DRONE, SPECTRE, CHOIR, BOWED, HOLLOW, TIDE, MALLET, LADDER, REVERSE and CREEP, draws WARP seldom, and never draws BRUIT, IMPACT, FRICTION, SHARDS, STATIC or GLITCH; then softer attacks, long tails, darker modulators, slow LFOs, no sirens, often an octave down. On EXPERIMENTAL it favours WARP most, then GLITCH, BRUIT, FRICTION, SHARDS, STATIC, SHAPER and CLANG, brighter and bent more often, and never draws SPECTRE, CHOIR, BOWED or TIDE.

Macros.

ANIMA — a lo-fi synthesizer played by a simulated hand

ANIMA is the lo-fi engine: each voice runs at half the sample rate (22.05 kHz, so nothing above 11 kHz), its samples drawn out to the full rate by straight lines between them. Its pitches, rates and filters are scaled to sound where they would at the full rate; what goes is the top octave of air, and half of the chip's time.

A fixed-point port of the anima opcode from Vascular, rebuilt for Tonitor. While a key is held, a simulated finger rests on a virtual surface and drags one figure after another (orbits, figures of eight, scribbles, slow glides, now and then a flick), pressing in slow swells, and now and then lifting to land elsewhere. A ghost finger comes and goes on an irregular clock. Where the finger is, how hard it presses, how fast it moves and how long it has been down move the timbre, never the pitch.

The voice: two wavetable oscillators (24 band-limited single cycles), an FM pair, a stack of copies, a grain cloud, a filtered noise, a resonant filter, a wavetable tremolo; then the hand's chain: a downsampler, a waveshaper, a phaser, a second filter and a comb resonator tuned to the note. Each new sound is a design: which of these are in, on which waveforms, and for every parameter which gesture moves it, over what range, along what curve, plus a mod matrix of three to seven routes and Anima's eight sliders, drawn, often far from their middle.

Twenty-two kinds: HAZE, VOYAGE, GLASS, BELLS, GOLDEN (Anima's own) and BREATH, GRIT, SWARM, TIDE (waves of noise over a low drone), CHOIR (vowels, a formant the hand moves), SHARDS (glass grains scattered and crushed), BOWL (a beating inharmonic hum in a ringing comb), DUST (sparse crackle over a dark drone), MACHINE (a pulsing, folded mechanism), PLUCK (a burst through the comb tuned to the note, dying away), REED (nasal, through a formant the hand moves, a breath in it), FOG (a stack under fog, a slow phaser drifting through it), ORGAN (drawbars, a rotary tremolo, a little drive), BITS (pulses in few bits: the rate crushed and dragged about, folded), DRIFT (two saws drifting against each other, a chorus the hand moves), MURMUR (a dark cloud of noisy grains) and HOWL (noise through a resonance so sharp it whistles, swept by the hand).

The filter follows the keyboard, so low notes are not muffled nor high ones shrill; the second oscillator's interval suits the path (consonant on AMBIENT, anything on EXPERIMENTAL); and an AMBIENT sound nearly always has a resonant space to ring in. On AMBIENT, ANIMA draws mostly HAZE, GOLDEN, VOYAGE, TIDE, CHOIR, BOWL, FOG and DRIFT, never GRIT, SHARDS, MACHINE, BITS or HOWL, with a darker tone, more space, a slower hand, long releases and no crusher. On EXPERIMENTAL it draws mostly GRIT, SWARM, SHARDS, MACHINE, BITS and HOWL, never HAZE, TIDE, CHOIR, FOG or DRIFT, and makes them wild: the sliders near their tops, the resonance often screaming, a crushed sample rate, folding drive, a band of noise and scattered grains, often a fast tremolo, the comb ringing hard.

In Vascular a design plays up to six fingers, each a voice; here a voice has one finger on the sound. ANIMA plays from the shared pool of voices; PLUCK is the lightest kind, FOG and BREATH the heaviest.

Macros.

CALIGULA — an organism

After the architecture of SOMA's LYRA-8 as Miguel Moreno's LIRA-8 emulates it (BSD licence), rebuilt for Tonitor and bent towards dark, restless textures. Eight oscillators in four pairs on two sides; each a triangle that its pair's sharpness pushes towards a square; each with a sensor and an envelope, slow (a long swell, a longer fall) or fast; each pair frequency-modulated at audio rate by its partner, the other pair of its side, a pair of the other side or the total feedback (the whole organism, saturated, fed back in). A hyper LFO of two LFOs (alone, AND, OR, XOR) opens and closes the modulation and gates chosen pairs into irregular rhythms; a short modulated delay (two lines, ~35 ms) choruses, flanges or warps it; a drive.

A CALIGULA track is played like the others: the keys play the scale's notes, and it is silent until a key is down. A key wakes the organism at that note; a second key on top moves the whole organism to the new note at once (a snap, not a glide), and letting go of it goes back to the key still held; letting go of the last key lifts the hand and the organism rings out. It is rooted: tuned around the note played, in intervals of it (octaves, fifths, unisons and semitone clusters that beat, tritones, the depths). The hyper LFO moves timbre, never pitch: no sirens. It is one organism a track, outside the pool of voices: its cost is the same whatever the number of notes.

Nobody touches the eight plates: a simulated hand does, while a key is held. Each species has its own hand: how often it touches, how long a finger stays, how many fingers at most, its favourite plates, quick taps against long holds. The first finger stays down until the key is let go, so the sound never drops out under a held key. Around the hand the organism has a life of its own: the modulation depths and the sharpness wander, oscillators fire in bursts at irregular times, and now and then the feedback and the drive surge for a moment. A pair's envelope may be slow: a swell of seconds, a release of up to nine seconds after the key is let go.

The hand often has a phrase: two to four plates it keeps coming back to, varied now and then, often on a pulse of its own (long, short, short, longer), so it plays like someone rather than like chance. HOME draws a new organism from ten species, tuned on one of ten sets of intervals (pillars of octaves and fifths, semitone clusters, the depths, the harmonics, unisons, tritones, fourths, a minor seventh, open fifths, a quarter-tone cluster):

On AMBIENT, CALIGULA draws SPORE, VEIL and LITANY most, then UNDERTOW, CARRION and MOTH, sometimes RUST; tuned on roots, fifths, octaves, depths and unisons; slow swells, softer edges, fewer bursts and surges, a slower hand. On EXPERIMENTAL it draws WIRE, THORN, HIVE and RUST most, never VEIL or LITANY; semitone clusters and tritones; sharper, more driven, more bursts and surges, a quicker hand.

Macros.

RUSSOLO — noise, logic and broken buffers

RUSSOLO re-makes the techniques of Robert Heel's Noisferatu (GPL-3.0) in fixed point, for the keys. It runs at a third of the sample rate (about 14.7 kHz) in 10-bit values, each held until the next (the grit of a small DAC), then reduces its bits and holds its samples further as the sound says.

A RUSSOLO track is played like the others and is silent until a key is down: the key opens an envelope and sets the pitch (the oscillators' frequency, the speed a buffer is read at, the rate noise is sampled at); a second key on top moves it there at once; letting go of the last key lets it fade. Like CALIGULA it is one organism a track, outside the pool of voices; more notes cost nothing more. It is the lightest engine. HOME draws one of seventeen kinds:

Its level is measured when it is drawn, and never raised so far that its loudest click could clip. On AMBIENT, RUSSOLO draws CHORD most, then DUST, CRACKLE, BLIPS, WALK and WANDER, never the logic kinds (NOR, XOR, RING, CASCADE, CLANG), JUMP, BEND or QUAD; clean (9–10 bits), slow attacks, long releases, calmer chance, no major chords. On EXPERIMENTAL it draws NOR, XOR, CLANG, BEND and QUAD most, never WALK or CHORD; crushed to 4–9 bits, often sample-held, abrupt attacks and short releases, chance driving it hard.

Macros.

DRUID — strings and resonant bodies

DRUID is a fixed-point port of the resonators of Mutable Instruments Rings by Émilie Gillet (MIT licence). It plays from the shared pool of voices. Each kind is one of Rings' resonators and an exciter:

On AMBIENT, DRUID favours BOWED, HARP, DRONE, BELL and BOWL, with long decays that carry on after the key is released. On EXPERIMENTAL it favours RATTLE and PLATE, with shorter decays, faster dust, extreme positions and a stronger damping when the key is released. Releasing a key damps the sound by an amount set per sound, from ringing on to stopping short. Each voice's delay lines are 16-bit and use the memory an ANIMA voice would use: a string reaches down to about 29 Hz, and sympathetic strings that would not fit their shorter lines are tuned an octave up. HARP and DRONE (a string with three sympathetic strings) are the heaviest sounds of all the engines.

Macros.

BAYAREA — a West Coast voice

BAYAREA is a fixed-point port of the bayarea opcode of Vascular, contributed by its author. It plays from the shared pool of voices. Each voice has:

• an oscillator that morphs from sine through triangle and square to saw (SHAPE), its frequency modulated linearly, through zero, by two sines at ratios of it (0.66 and 3.3 by default, other ratios on some sounds), each ratio wandering slightly and slowly;
• a wavefolder (FOLDS), reflecting the wave back into range;
• a 12 kHz smoothing low-pass and a trace of noise;
• either a low-pass gate, where a resonant low-pass and an amplifier are struck together by one-shot envelopes (an attack of 2–3 ms and a decay), or a sustaining envelope over two resonant low-passes (an attack while the key is held, a release when it is let go). The filters sweep from 300 Hz to the sound's peak frequency, higher for louder notes;
• a saturating output stage (tanh, then a soft clip) with its own drive;
• a bank of three resonators (508, 270 and 1153 Hz, ringing for 1–1.4 s), mixed in by the sound's amount;
• an LFO (triangle, ramp, square or random steps) that moves the shape, the folds, the two FM depths, the attack, the peak, the decay and the resonator mix, by amounts drawn with the sound.

Changed from the opcode: the square and saw are band-limited with polyBLEP instead of being summed from 44 partials (too costly for this chip), and the opcode's reverb is replaced by the track's sends to the master delay and reverb, keeping only its resonator bank.

On AMBIENT, BAYAREA favours BONGO, CHIME, SWELL and DRONE. On EXPERIMENTAL it favours PLUCK and FOLDED, with more drive and folding and other FM ratios more often. The percussive kinds (CHIME, FOLDED, BONGO) end quickly and free their voices.

Macros.

HIVE — a swarm of oscillators

HIVE is a port of the SWARMER machine of DigiRust, contributed by its author, extended here with inharmonic and textural kinds. It plays from the shared pool of voices. Each voice has seven oscillators, and each sound draws, for every one of them:

• its place relative to the note: the note itself, an octave or a fifth, a step of a cluster (quarter-tones, seconds), or an inharmonic partial (the modes of a free bar, a bell's partials, a stretched harmonic series, or ratios at random);
• its share of the spread that DETUNE sets (symmetric, clustered, to one side, at random, or in pairs);
• its wave, a position along sine, triangle, saw and square (neighbouring waves crossfaded);
• its level, and which of three LFOs moves its pitch and its level, and at what phase. The LFOs' rates are drawn too, from about 0.02 Hz to a few Hz depending on the kind; MOVEMENT scales their depth.

The seventh oscillator is the main one, set against the other six by MIX. Each voice also has a slow noise on every oscillator's pitch; how closely it follows the key (fully for the melodic kinds, partly or hardly at all for the textural ones); noise; a ring modulation of the first oscillator by the main one; a 4-pole filter (two state-variable filters, low-pass, band-pass or high-pass) whose cutoff follows half the key's movement and is swept by its own envelope and by the first LFO; an ADSR envelope on the level; and a drive (tanh).

Changed from DigiRust: the waves are computed as they play (the sine from its table, the triangle directly, the saw and square band-limited with polyBLEP) instead of read from band-limited tables, which would not fit in RAM here; the filter, envelopes and drive are Tonitor's own. Silent oscillators are skipped; with three HIVE voices or more sounding, oscillators 12 dB under the loudest are skipped too, to save the chip's time.

CLUSTER, METAL, SPECTRA, GROUND, AIR and TIDES are meant for non-melodic, textural use. On AMBIENT, HIVE favours PAD, DRONE, WASH, SPECTRA and TIDES, and makes the LFOs slower, the sound darker and the attacks longer. On EXPERIMENTAL it favours STAB, CLUSTER, METAL, GROUND and AIR, and adds more noise to the pitches, more drive and, sometimes, a ring modulation. AIR is the lightest kind; LEAD the heaviest.

Macros.

OBRADOR — an analog polysynth

An analog polysynth voice after the Oberheim SEM and the two-voice Oberheims, written for Tonitor with OberVave (an Oberheim-style firmware for the FM-1, by zvenson) as its frame of reference; the same engine as Tonitor's on the FM-1, with four more macros here. It plays from the shared pool of voices. Per voice: two oscillators (saw, pulse or both, band-limited), the second detuned or an interval away, hard-synced or cross-modulating now and then; in the lush kinds a second voice card, detuned against the first; a drive into the SEM's 12 dB filter, its output morphing from low-pass through notch to high-pass, its resonance soft-limited; a second low-pass stage for 24 dB, or the band-pass; filter and amplifier envelopes on analog curves; an LFO that comes in after a delay; and each card's own small offsets of tune and cutoff with a slow drift. The pitch wheel bends it.

On AMBIENT it is softer, slower and darker, and favours STRINGS, PWM PAD, DRONE and SWELL. On EXPERIMENTAL it is harder (more drive, more resonance, cross-modulation now and then), and favours SYNC, NOTCH and METAL.

Macros.