MIDI tracks and voice modes

Summary

MIDI 1 and MIDI 2 are two complete synths inside the Circuit Tracks: each track keeps sending MIDI and also sounds through its own engine, with up to 4 voices (6 in FM). The voice mode decides how notes are shared out among those voices: eight modes on pad 32 of the Preset view.

This document describes Beta 5.16, not tested on the device. Nearly all of it is already in RC4 and RC4.07; what is only in the beta is marked (Beta 5.16 only).

The voice mode has no CC or NRPN: it is chosen on the device and saved with the patch and the project.

Block diagram

A note takes two paths: it goes out over MIDI and, with the engine on, into the voice mode. Incoming MIDI only takes the second path.

Modulation acts on the engine's parameters, not on the note. With patch flip on there is no engine: the note goes out as a Program Change.

Views and menus

The Preset view is the centre of the track: that is where you choose the engine, the voice mode, the patch and the knob page. The other views deal with the pattern.

The step-drummer appears twice because there are two ways in: pad 30 of Preset, or repeating Note when it is already on.

Views

Pads of the Preset view

Menus on the pads

A menu takes over pads 9-24 while it is open; those pads stop loading patches.

Gestures with Clear, Shift and Duplicate

Engines

Each track has one engine out of seven, plus off, and the track keeps sending its MIDI with any of them. It is chosen on the row that pad 27 opens.

Oscillator

WAVE (K7 of page 2) is a continuous position between shapes: 0 sine, 42 triangle, 84 saw, 126 square. SHAPE (K2) acts differently on each shape; between two shapes it acts on both.

Saw, supersaw and pulse use PolyBLEP, with about 40 dB less aliasing on high notes. With pad 28, OSC 2 modulates OSC 1 with FM, ring, sync and bitwise modes. Two notes at once = paraphony in the mono modes with two oscillators.

VA-drum

The Sustain knob is the pitch decay and the Release knob the filter decay. The LFO speed gives the noise level, and the LFO is replaced by random values. In poly each hit has its own pitch and volume envelopes and its own noise: a new hit does not cut the earlier ones.

Granular

The note mode (Shift + K6 of page 2) changes what the notes do.

With Shift + K4 above 0, each grain goes to a random side. The track's pan decides the proportion. The source (Shift + K8) is the capture or a drum's sample.

Sample

C3 (note 60) is the sample as it was recorded; an octave up, twice as fast. The VCA stays open and the sample plays to its end. Samples are chosen in the expanded Note view, with a different sample per step (sample flip).

K7 of page 2 is the stereo width: each note plays the chosen sample on the left and a second one on the right. Shift + the chosen sample switches to picking the second. The note lasts as long as the longer one.

FM

The volume comes from the operators' envelopes: the VCA stays open and the ADSR of page 1 moves filter, pitch and brightness. SHAPE, Env → shape and LFO → shape change how much the modulators modulate (× 0.27 to × 3.7), so everything that moves those values moves the timbre.

Each operator is sustained or percussive: Shift + K1-K4 to the right gives attack, to the left its own decay. There is one release for all, longer the harder the note.

The starter sounds (pad 8 held): piano, electric piano, organ, pluck, harp, marimba, bass, bell, strings, pad, flute, clarinet, brass, kick, snare and hi-hat.

Voice modes

There are eight modes, a combination of two decisions: how many voices sound, and what a new note does with other keys held. A project that never chose a mode starts on poly.

The number is the menu's pad. Modes with the same name share a colour: retrigger green, legato yellow, glide teal. Uni always-glide is violet and poly magenta.

The mode shares the notes out among the voices; then each voice's level drops according to how many are sounding, and all of them go through the track's filter and effect.

How to choose

With the engine on, a tap on pad 32 opens the menu on pads 17-24, with the current mode bright. Touching a pad chooses the mode. Shift + pad 29 does the same without opening the menu: it steps through the eight in that order, and with Shift pad 29 shows the mode's colour.

With the menu open, two knobs adjust the modes:

What each mode does

In uni legato the envelopes of FM and VA-drum are not retriggered either.

Voices per engine

Glide works on oscillator, VA-drum and FM. Sample mode and the granular do not slide.

Each track has its own maximum; only FM voices are shared between the two. If the second track goes into FM poly or unison, the voices of both are cut at once to share out.

What belongs to each voice and what to the track

Voice stealing

With all voices busy, a new note takes the voice of the track's oldest note, with a 2 ms fade. A released note keeps its voice while its release sounds, so with long releases the voices fill up even if you play single notes.

Chord level

Each voice drops according to how many are sounding, so the sum does not clip. The factor is √(2 / n), and the unisons follow the same rule.

Voice limit

With two or more own voices sounding, the device turns voices off before the DSP runs out of time and a rattle is heard. FM is the engine that uses the most. With a single own voice the limit does not act.

1. 1. Every 2 ms it measures how much time the DSP has left.
2. 2. If it is tight, it turns off the lowest released voice, FM ones first. If none is released, it turns off the oldest held note.
3. 3. It turns off at most one voice every 12 ms, or every 4 ms if very tight.
4. 4. The track goes on with the voices that fit, 2 at least. A new note first turns off the lowest released one.
5. 5. Every 2 s without trouble it tries one voice more, up to the maximum.

Synth 1 and Synth 2 do not lose voices through this: with two or more own voices sounding, the device stops turning theirs off for lack of time. The ones that go off are the own synth's.

For more voices at once: shorter releases, fewer FM operators at a high level, or a single track on FM poly.

Saving the mode

The mode, the glide time and the detune are saved with the own patch and with the project. A patch without them leaves the current values.

Knob pages

With the engine on, pads 1-7 choose what the 8 knobs do, and Shift gives a second layer. Type knobs show the type's colour, with the brightness of the position inside the type. A type knob takes at least 16 clicks a type (Beta 5.16 only): the LFO shape, the FM algorithm and the granular's note mode go to 16.

Page 1: VCA-VCF

Page 2: OSC 1

On oscillator, VA-drum, sample and FM.

Page 2: granular

Page 3: OSC 2

Page 4: sequenceable knobs

These are the 8 values recorded as automation with Record + Play. By default: TUNE, Release, Env → level, Env → filter, Filter, Resonance, LFO speed and Effect.

Shift + knob chooses the destination among the 33 parameters, 4 clicks per parameter. While you choose, pads 9-24 show where the destination lives. Clear held and then Shift + knob restores the default.

Non-sequenceable knobs (Shift + pad 4)

Eight knobs with an assignable destination that are not recorded. Pad 4 shows pink. By default: Attack, Decay, Sustain, SHAPE, LFO → filter, Env → pitch, MIX OSC 1 / 2 and VCA gain.

A destination that is also on the sequenceable knobs is recorded, as from any page.

Page 5: modulation

With VA-drum, the LFO is still its noise.

Page 6: matrix

Eight modulation sources, in the next section.

Page 7: FM

A carrier's level is its volume; a modulator's, how much it modulates.

Modulation

The engine has its own ADSR and LFO, and the matrix adds eight sources that move any of 33 parameters. The matrix is added when sending: the parameter's saved value does not change.

LFO

K7 of page 1 is bipolar: right free, left synced. Shift + K8 of page 5 chooses the shape, with the LED in its colour: one step every 16 clicks (Beta 5.16 only; before, 4).

Modulation matrix (pad 6)

With K1 (velocity) at 0, the global velocity controls of the Setup view (K1 velocity → amplitude, K2 velocity → filter) take over: soft notes quieter and darker. (Beta 5.16 only)

The knob's position is both the destination and the amount:

• Fully left, off.
• Each destination takes 16 steps, 2 clicks per step. The first is the destination with no amount, with the LED dim.
• The LED's colour is the destination page's, and its brightness the amount.
• The sources note, random, LFO 2 and stepped random go up and down; the others only up.
• Several sources on one destination add up.

Modulation reaches the engine about 100-250 times a second, shared among everything moving on the track.

Sequence and performance

The track uses the stock pattern, and the mod adds engine automation, step-drummer, arpeggiator and per-step variations. All of it goes out through the same voices and respects the voice mode.

Automation

The 8 sequenceable knobs record with Record + Play into 8 lanes of the pattern. There are several per-step gestures:

In the snapshot, a parameter with no lane takes one whose parameter is at its initial value, and that lane is erased first. If they do not fit, the first ones in the matrix's order stay.

Step-drummer

The 8 knobs are 8 pairs of steps of the pattern: each pair offsets a destination only on those steps. The LED shows the amount: dim with no modulation, brighter the further away.

The toggle moves one degree of the scale every 8 knob steps, from −8 to +8 degrees. With the step-drummer on, TUNE and Release stop playing and recording as automation, because it uses their lanes.

FX sequencer

With this engine, each step-drummer knob chooses a slot of the bottom row of Master FX: none, pads 26-31 or random. A slot with no effect plays the effect at the top of its column.

Jump sequencer

The track's notes make another track's pattern jump to the step they indicate, on the note's own step. (Beta 5.16 only)

While it points, the track does not sound. Each note, from the sequencer, the pads or the arpeggiator, makes the other track jump. Saved with the project.

Pad 27 blinks in the target track's colour. Pointing turns the engine off and turning an engine on stops pointing: only one of the two at a time. When it starts pointing the track goes to steps 1-16, and Octave only moves between 1-16 and 17-32: the Octave that cannot move any further goes dark, both in the expanded Note view. With the transport stopped, a pad sounds that step of the target track while you hold it, with no jump (on the drums, with the chosen sample).

If the target and the MIDI track have the same length, one jump is only noticeable the first time: on the next passes the target is already on that step. To hear it on every pass the pattern needs two jumps: one to move it and one to bring it back.

Arpeggiator

It works per track and pattern, in Pattern Settings with Shift. Notes are arpeggiated in the order they were pressed.

Four sources reach the arpeggiator: the pattern's chords, held notes, a held step with the transport stopped, and the external keyboard if Setup's Note button is on. With Record the chord is recorded, not the single notes.

Per-step variations

Playing live

Each note of the chord goes through the voice mode: in poly it sounds up to the engine's maximum of voices.

Saving

The own synth lives in three places at once: the project, the pack's patch and the device settings. When a project that carries it loads, the project's wins; an older one leaves the sound as it was.

The Synth 1 / 2 patch file does not change: the own patch goes in the part of each record the original does not use.

What is saved where

What is lost at power-off

• Everything changed since the project's last Save.
• Latched notes and chords, and the chord screen's type and modifiers.
• The split keyboard and open views.
• The Octave semitone with Jankó.
• A patch waiting to be copied to another pack.
• The turn counters of frequency and fractal order, which reset on stop.

Limitations

• With no card, and on the S versions, the mod writes nothing of its own: patches are not saved and Save turns red. The project is saved.
• The CC editor saves in the template, not in the own patch.
• A patch from an old version loads without what did not exist yet: matrix off and default destinations.

MIDI control

Each engine knob sends and receives a CC or NRPN on the track's channel, with values 0 to 127 and 64 as the centre on bipolar ones. Voice mode, matrix, FM and knob destinations have no CC or NRPN.

All of it respects the CC Tx and CC Rx filters of the Setup view. Messages go out as the knob turns, with Clear too, and come in on the same number.

Notes and channels

With the engine on, the knobs send this map and never the template. With the engine off they send the template, editable with pad 25.

Selecting an NRPN

Send CC 99 (MSB), CC 98 (LSB) and CC 6 (value), in that order. The device remembers the chosen NRPN until the next CC 99 or 98. In the table, 4:13 means MSB 4, LSB 13.

Engine parameters

On granular, page 2 and part of page 3 use the same numbers with another meaning, in brackets.

Incoming CC and NRPN

Incoming CC and NRPN move the engine, but are not recorded into the pattern or forwarded over MIDI. Only the device's knobs write automation. With the engine off, the device does not take them.