Eurorack

Oxidzr as a Eurorack sequencer

Oxidzr doesn't output control voltage itself. Pair it with a MIDI-to-CV module and it becomes a deep external sequencer for a modular: eight sequencers, nine modes, generative and polymetric parts, all in one iPad.

What you need

A MIDI-to-CV converter. A Eurorack module, or a standalone box, that turns MIDI notes into pitch (1V/oct) and gate, and usually controllers into CV and clock into clock and reset pulses. Some take USB MIDI straight from the iPad; others take 5-pin DIN MIDI.
A way to get MIDI to it. Plug a USB-host converter into the iPad, or use a USB MIDI interface with a DIN output for a DIN-only converter.
The standalone app for the shortest path. Choose the converter or interface under MIDI Out in the transport settings (tap »). See Sequence hardware synths for connections.

What a converter does with each message depends on the converter: how many voices it has, which outputs follow which channel, what its CV outputs respond to. Set it up from its own manual, then match Oxidzr to it with the steps below.

A pitch and gate voice

Set the converter’s first voice to listen on channel 1, and patch its pitch and gate outputs to an oscillator’s 1V/oct input and an envelope.
Sequencer 1 starts in Mono on channel 1: one note at a time, which suits a single CV voice. Write a line, or tap Random.
Press ▶.

Shaping it for a modular:

Range: use Octave in the controls row (−4 to +4) to move the whole line into the range your oscillator is tuned for.
Legato: Tie on a Mono note overlaps it with the next one. Converters that keep the gate open between overlapping notes then change pitch without retriggering the envelope.
Ratchets: step Repeats retrigger the gate quickly within a step.
Velocity: each step’s velocity goes out as velocity, for converters with a velocity CV output.
Glide: Oxidzr sends glide as MIDI portamento (CC 65 and CC 5). Many converters don’t slew pitch from those, so for slides in the rack, patch the pitch CV through a slew limiter.

More voices

Give each sequencer the channel of a converter voice: sequencer 2 on channel 2, and so on, up to as many voices as the converter has.

Chords on mono voices: in Poly, Chord, Domino or Saga, ChMx sends each note of a chord on its own channel. With Channel 1, Lo and Span 3, a three-note chord plays one note on each of three voices.
A harmonised bass: a Mono sequencer with Follow set to a Chord sequencer always lands on chord notes. Mute the Chord sequencer to hear only the bass move.

Drum triggers

Converters with trigger or gate outputs usually assign each one to a MIDI note. Use Multitrack mode:

Set Scale to Chromatic so each track’s Note can reach any key.
Set each track’s Ch and Note to the trigger output it should fire.
Write rhythms with pads, Euclidean Apply, or the Kick, Snare and Hat generators.

Each track has its own length, speed and order, so trigger patterns can phase against each other. See Polymetric sequencing.

Modulation CV

If your converter maps MIDI controllers to CV outputs, Oxidzr’s mod lanes become CV sequences: 8 per sequencer, each set to MIDI CC with the controller number the converter expects, on the lane’s own Ch.

Each lane has its own Div, length and order, so a CV sequence can drift against the notes.
Rise Slew and Fall Slew glide between values. Rise off and Fall at 100% snaps up and falls away, like a simple envelope per step.
Values are sent as 7-bit MIDI controllers (0 to 127), so the converter decides the voltage range.
Stochastic Attack and Decay send Expression (CC 11). Map it to a CV output and into a VCA for per-note swells.

Clock and reset

Set Clock to Send in the transport settings. Oxidzr sends 24 ticks per beat while playing, plus Start when you press play and Stop when you stop. Converters with clock and reset outputs typically derive them from these, so clocked modules in the rack stay in time and restart with Oxidzr. Oxidzr always sends Start, not Continue, because its patterns restart from the first step.

Oxidzr doesn’t follow incoming MIDI clock, so it should be the clock source for the rack.

Generative parts for the rack

The modes that suit a modular best:

Stochastic: a melody generator driven by probabilities. Capture a phrase you like and let it mutate slowly. See Generative sequencing.
Matriceal: four tracks of independent lanes, each on its own channel, for evolving parts that stay in key.
Saga: stages of any length, with Single, Multi and Hold gate types, and random pitch range per stage.
Accumulate: any note in Mono, Poly, Domino or Saga can climb or fall a little every time it plays.