Exercise C

Exercise C: Sequencing

Make a VCV Rack patch that uses one or more sequencers to generate loops consisting of pitch changes.

Instructions

Create a patch that uses an envelope to produce separate notes. Test it with keyboard input.

Then drive this patch from a sequencer instead of a keyboard. Sequencers have a series of states, called steps, that change to produce a regular rhythm. The series normally loops indefinitely. Sequencers have at least one CV output and either a gate or a trigger output. You would use a CV output to set oscillator frequency and the trigger output to start the envelope for each step. You can use other CV outputs of the sequencer to control additional parameters, such as filter cutoff frequency.

A gate signal produces a high voltage when the gate opens and a low voltage when the gate closes. For example, if using MIDI, a gate opens when it receives a note-on message and closes when it receives a note-off message.

A trigger signal simply produces a brief high voltage in response to a note-on input, but it ignores any note-off inputs.

Use a PULSES module hooked up to a SCOPE module to compare these two types of signal.

VCV Rack comes with one sequencer, called SEQ-3, that has three rows of knobs, with 8 knobs per row. Three jacks — CV1, CV2, and CV3 — carry the CV outputs for the three rows. The TRIG output carries a trigger signal that makes a brief high voltage at the start of each step.

A sequencer module in VCV Rack

Sequencers generally have a built-in clock. But most also have the ability to take an external clock input instead, allowing you more flexibility in the duration of the clock signal and its timing. Note the “Clock generator” and “Clock modulator” tags in the module picker. You can also use an LFO pulse wave as a clock signal.

Regardless of your clock source, the RUN button must be on for the SEQ-3 module to do anything.

Other sequencers to try include any in the JW-Modules and Bogaudio brands.

Submission

  • Save your rack to disk as “Exercise C.vcv,” and submit this in Canvas.

Grading Criteria

This assignment will be graded pass/fail. You may ask for help with it during tutorial before submitting it on Thursday night.