Volca Modular Tutorial

Intro

Korg Volca modular is a semi modular synthesizer that features 8 modules and a 16 step sequencer.  The synthesizer is inspired by the “west coast” synthesis approach.

West coast synthesis

West Coast synthesis is an approach to musical synthesis and electronic musical instrument design developed by Don Buchla starting in the 1960s. West Coast synthesis favours experimental approaches to music-making, often bringing into question the nature of a composer/performer's interaction with their instrument, as well as the "rules" by which music is organised.

Many say that West Coast synthesis hinges on the use of complex oscillators, wavefolding, lowpass gates, and dynamic depth FM

That adds up as if we look at the modules we see we have an fm style oscillator setup with a carrier and a modulator, and we have a fold function as well as modulation amount and ratio.

The other modules included are woggle (which is basically a sample & hold). Two functions (or envelopes), two low pass gates (which contain lpf), split (which is like a mult), a space reverb effect and a utility module.

Sequencer

So the first thing I’ll explain is the sequencer. Pressing the play button will start the sequencer running and from there you can start exploring the different functions.

Memory

The sequencer can store 16 patterns in memory, to access a slot just hold the memory button and select one of the slots by pressing the key.

Scale

You can also quantise the sequencer to lock to a scale. Press function & 1 which will light up the available options which can be seen written along the bottom, select the scale you want and press function to exit.

Tonic

You can also change the tonic (or root note) to quickly transpose your sequence.

Microtuning

Microtuning allows you to adjust the pitch of each note in the selected scale. Pressing function 3 will bring up the notes on the keyboard. You can then select a note and use the microtune dial to adjust the pitch with a range of +100c and -100c. Function 4 will clear those settings.

Octave

You can change octave up or down on the keyboard with function 5 and 6.

Randomize

The randomize section lets you randomize either the notes in your sequence, the active steps or the microtuning.

Gate

Function 10 changes the gate from short too long.

Mode

Bounce makes the sequencer run back and forth instead of repeating from the start every time.

Stoch essentially randomizes every note. The manual says, In stochastic mode, at each sequencer step the next step will be decided randomly among four choices: one forward, skip one forward, one backwards, or repeat same step. Each time stochastic mode is enabled a different probability will be assigned to each choice.

Motion

Motion, when enabled, let’s you record automation on any dial. There is also an option here to clear those recordings.

Clear

Finally, the clear option allows you clear out any active step settings or all settings you’ve edited.

Recording

Live recording 

To live record all you have to do is press play and record and play in any notes you want. 

Step recording

To step record you will press function and the record button. These will start flashing and you will see step one is waiting for you to choose a note. Once you choose a note for step one it will proceed to step 2. If you want to enter a rest, just press the play button to progress to the next step without entering a note.

Module default routing

So let’s take a look at the modules and how they are routed by default. It’s important to understand how the signal is passed around as this will make it easier to make your own patches.

If you look at the front panel you can see how each module is connected by default. If you look closely you can see these lines that show the default routing.

We can see that the output of the oscillator goes to the signal input of the low pass gate. The output signal of the low pass gate goes to the space out which is the final output.

In order to hear the sound of the oscillator we have to open the gate to let the sound through. This is done by playing a note from the sequencer which sends a trigger to the sequencer module which then sends a trigger the the function (envelope) the result of which is sent to the low pass gate which opens and closes again depending on how you set your attack and release.

The Volca Modular comes with this handy card which shows you all of the patch point connections that are available. If we look at the key we can see inputs are transparent and outputs are in blue. We can also see audio signals will have a rounded edge where as cv (control voltages) are square.

If you're new to modular the basic idea is if I wanted to modulate this dial (demonstrate space effect) I could use another module's output to send cv messages to this input, which would be the same as me manually turning it up and down. So if I take the woggle output and go into the amount input on the space effect we can hear it’s now being controlled by the random values being sent by the woggle (sample & hold) module.

You do have this motion automation record option so you don’t really need to patch anything like this as you can just record your movements, but the patching method will produce a much more random result that changes every time, whereas your recording will be the same every time. So the point of this device is to be more experimental which is inline with west coast synthesis. 

Sequences

Inputs: clock offset 

Outputs: fourth, third, half, gate, pitch 

This module is the interface to the internal sequencer. The pitch output is the pitch of the current step. A gate signal is sent to the gate output when a note should be played for the current step. A gate will also be sent to the other outputs according to a gate counter: • /4 (fourth) : once every four gate • /3 (third) : once every three gate • /2 (half) : once every two gate The clock offset input can be used to modify the sequencers tempo by +/- 20BPM.

Source

This module consists of a pair of triangle VCOs (voltage controlled oscillators), one called the carrier, and the other the modulator. The signal generated by the modulator is used to vary the frequency of the carrier, this process is called frequency modulation (FM). Frequency modulation allows users to create sounds with very rich harmonic content, and often with a metallic characteristic. The output signal is then passed through a wave folder circuit, controlled by the FOLD knob, which inverts the wave shape at certain thresholds in order to further increase the harmonic content.

• Additionally, the oscillator’s overall tuning can be modified by holding the FUNC button and using the RATIO knob (+/- 50 cent).

Functions

This module consists of two distinct function generators (often called envelope generators). 

AHR generator (left) 

Inputs: gate, attack, release 

Outputs: positive, inverted, end trigger 

This is a three phase generator: attack, hold, and release. It generates a signal that rises according to the attack time at the start of a gate signal, holds until the end of the gate, then falls for the duration of the release time. When the release time is reached, a trigger is sent to the end trigger output. 

Rise-Fall generator (right) 

Inputs: trigger, shape, time 

Outputs: positive, inverted, end trigger 

This generator only has two phases, rise and fall. The shape determines the balance between the rise and fall time, whereas the time determines the overall length of the rise-fall cycle. When the cycle ends a trigger signal is sent to the end trigger output. 

LPG

DUAL LPG (Low Pass Gate) 

Inputs: signal, level 

Outputs: signal 

These are two individual low pass gate circuits, which consist of the combination of a low pass filter and voltage controlled amplifier. The level input determines both the gain of the input signal passed to the output, but also the frequencies that are let through. This means, a high level will give a loud and bright sound, whereas a low level will give a quiet and muffled sound. The maximum cutoff frequency of the low pass filter is determined by the CUTOFF knob.

Woggle

Inputs: sample, trigger 

Outputs: stepped, smooth 

This module is a sample and hold circuit that defaults to sampling a pink noise source. A sample and hold circuit samples a voltage when triggered, and holds that voltage until triggered again. The sample input can be used to override the noise source and sample any signal. Everytime a trigger signal is received on the clock input, the value of the sample input is remembered and sent to the stepped output. The smooth output will look similar to the stepped output, but changes of value will glide smoothly instead of jumping immediately to the next sampled value.

Utility

Inputs: a, b, c 

Ouputs: a+bxc, a-bxc 

This module allows to combine and attenuate signals in various ways. “c” is used to attenuate input “b”, and the result is then added or subtracted from input “a”. All inputs can be either polar or bipolar, and both control and audio signals are supported. Additionally, when there are no connections to input “b” it defaults to 3.3V, in which case a fixed voltage offset can be applied to “a” by controlling the value of “c”.

Split

Inputs: input 1, input 2 

Outputs: output 1-A, output 1-B, output 2-A, output 2-B 

This module duplicates an input to two different outputs, so that a signal can be split and connected to more than one output. Using this module backwards is also possible, in which case it becomes a passive signal mixer, combining two control or audio signals into one.

Space Out

Inputs: audio, amount 

Outputs: audio 

This module applies a digital spatial effect to the input audio signal and outputs the audio to the headphone jack, and the internal speaker. The output can be used to patch the resultant audio to another input.