Klavis Grainity Granular VCF User manual

Klavis Grainity user manual V1.0 Page 1of 17
Grainity Granular VCF
Digitally-controlled full-analog Granular + Multimode VCF
Introduction
The Grainity brings a unique and never-heard-before concept to the world of analog VCF.
While being based on analog filtering only, the Grainity expands and enriches the sound in
creating subharmonics, harmonies, unison, flanging effects and formant filtering all at once. The
module presents two sections, the Granular filter itself and a typical Multimode filter, each with
its own output. A third output offers a mix of both filter paths. Numerous controls and CV allow a
very wide palette of results.
Grainity Granular VCF
Detect
Klavis
Input
Struct Div Mix
G.VCF MixM.VCF
QFM
V/Oct
HP
BR
IN
LP2
Mix
Structure
LP4
Div
BP
F Q
Type inv
Track
TrackFrq
Features at a glance
•Unique concept of granular VCF
•100% analog audio path
•Two simultaneous filter flows, Granular VCF and
Multimode VCF, with separate outputs
•Mixing of both filter’s output to a dedicated out
•Phase inversion switching between the two filters
•Shared frequency and resonance controls
•Multimode filter with various types and poles
•Self-resonance capability
•Granular filter with unique controls:
oStructure selection from a predefined list
oDivision to extend the grains length
oPhase setting of the cycling point
oTracking and offset tuning of the cycles
•Detect input for cycling unrelated to audio input
•7 CV inputs to control all settings
•Current settings maintained over power cycle
•Firmware update via a simple audio file
•Scratch-resistant printed aluminum panel
•Compact and skiff-friendly module

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Installation and security
Purpose
This module is meant for installation in a Eurorack-compliant chassis.
It adheres to Eurorack Doepfer™mechanical and electrical specifications.
Do not attempt using this module in other mechanical or electrical contexts.
Installation
Before the installation, disconnect the mains power supply from your modular system. Some
power supplies are not safely isolated; there is a risk of injury!
See in the specifications if this module requires 5V from the supply rails. If 5V is needed and your
rack is not providing 5V, do not attempt connection! A Klavis NoDrain adapter can provide the
missing 5V rail.
Check that the current consumption requirements of this module, when added to your installed
set of modules do not exceed the available current from your supply. This is done by adding up
the current draw of all modules (mA) separately for each of 5V, 12V and -12V rails. If any of these 3
sums exceeds the available current of your supply for that voltage, do not connect the module to
your system; you need a stronger power supply.
The provided supply flat cable can only be inserted in the appropriate orientation at the back of
the module, so there is no risk of error on that end. However, you should pay attention to the
orientation of the cable in the socket of the supply PCB inside your chassis. Cheap sockets
without shrouding may allow you to plug in the connector the wrong way!
The red stripe on the cable should match a stripe printed on the supply board. The stripe also
indicates the -12V side. In case there is no stripe, a -12V marking is a safe indication of the
orientation.
Double check that the connectors are fully inserted and correctly oriented before switching on
the power supply. In case of an anomaly, switch off the power supply immediately and check
everything again.

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Firmware update
If needed, the product can be updated by playing an audio file such as “Grainity_1.00.wav”.
Check on Klavis.com that you have the latest firmware version for your product.
If there is none to be found, there is none needed ;-)
Procedure
•Connect a mono or stereo cable between your audio playing device headphone output
and the Grainity Struct input.
•Prepare to play the audio file
•Set the play level at two thirds
•While pressing the Track and Type buttons, switch on your modular case supply
•The display shows the current firmware version [Fxy], interpreted as “Firmware X.Y”.
•Start playing the audio file
If everything goes fine
•As the update is progressing, the display shows a value increasing towards 100
•When the blue Track LED flashes and the display shows the new firmware version, the
updated was successfull
•Press any button to restart the module
If the sound level is too low
•Stop audio playback
•Slightly increase the audio playback level
•Start audio playback from the beginning
If there is an error during the playback
The display will indicate [Err] and all red LEDs are flashing.
It is possible that the sound setting was too loud to begin with.
Diminish the sound level drastically and restart the procedure.
Playback error can also be due to various parasitic sound causes:
•Touching the cable
•Using sound-generating features of your phone or computer
•Some power saving feature affecting the audio playback
•Surrounding noisy modules, bad electrical grounding or modular supply noise
•Check that you have not created a ground loop (e.g. computer used as file player!)

Klavis Grainity user manual V1.0 Page 4of 17
What is the Grainity
Granular?
The word granular was chosen for this filter module in relation to the concept invented by the
composer Yannis Xenakis, and which is described as assembling small chops of sounds - he called
grains - according to a pattern. This is exactly what the Grainity does, no more no less ... but,
digital control allows doing it in ways that are decades away from what tape and scissors allowed
at the time.
Technology wise ...
In the granular section, the incoming sound cycle is determined in order to step through various
filtering and phase variations of itself according to predefined patterns. The controls allow
alterations to the phase, frequency offset and frequency division of the filters cycling. This comes
in addition to the usual filter frequency and resonance controls.
What the Grainity is not
Technology wise ...
Despite relying on a microprocessor, the Grainity is not a digital audio processor. At any time, the
sound remains in the analog domain and goes through analog circuits from in to out. The
onboard digital processor does not convert or generate audio signals; it is there to control the
analog circuitry and manage the interface and display.
Sound wise ...
Several digital modules offering granular processing rely on layering the sound grains, which
leads to blurry and cloudy textures. Layering of the grains is a late addition to the concept of
granular synthesis and is not a mandatory feature of the concept. The Grainity does not use delay
lines or sampling memory but is nevertheless true to the foundations of the granular synthesis
concept.
The granular VCF in the Grainity is unconventional in that, most of times, it is not filtering the
sound in the common expectation of removing something. Typically, the granular process adds
more than it removes by expanding both the lower range, creating subharmonics, and the upper
harmonic contents in multiples ways.

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Signal flow and overview
Here is a conceptual representation of the Grainity controls and connections.
Granular VCF
Multimode VCF
FM CV
V/Oct CV
Q (Resonance) CV
Freq
Type
Phase
inversion
Phase/Track
Division Structure
Detect
Input
Track
mode
Mix
Mix
Mix CV
Mix
M.VCF
G.VCF
CVCV
CV
Selection
Struct Div
Sum
Sum
F
Q
The incoming audio is feeding the Granular and Multimode sections. The granular filter has a
Detect input that allows replacing the incoming audio detection with any arbitrary cycling signal.
Each filter section has its own output and settings; only the usual VCF frequency and resonance
controls and their CV inputs are shared between both sections.
A dedicated Mix output with a knob and CV control allows balancing both filters.
A phase inversion setting between the two sections is useful when these are mixed; otherwise, it
has no audible effect. Inversion usually reduces the fundamental tone, usually resulting in a
thinner sound.
The output of the multimode filter is selected among various filter types.
The remaining controls are dedicated to the granular VCF and are explained further on.

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Panel overview –shared and section dedicated controls
Shared controls
The knobs and jacks inside the colored area are shared
between the two sections:
1. Audio input jack
2. Frequency fader
3. FM (Frequency) CV jack and its bipolar gain control
knob
4. V/Oct CV jack
5. Q (resonance) fader
6. Q CV jack and its gain control knob
7. Mix output jack, Setting knob and CV input
8. Phase inversion push button (long press)
Multimode VCF controls
9. M.VCF, multimode VCF output jack
10. Filter mode selection LEDs and button (short press),
with 6 options:
oLP2, 12dB/Oct lowpass
oLP4, 24dB/Oct lowpass
oHP, 24dB/Oct highpass
oBP, 12dB/Oct bandpass
oBR, 12dB/oct band rejection also called notch
oIN, the unaltered input signal; sometimes
useful to blend with the rich granular result,
especially using the Mix CV control
Granular VCF controls
11. G.VCF: granular VCF signal output jack
12. Detection input jack, for audio or trigger/gates
13. Structure: CV, selection encoder, and first two digits
of the display
14. Divide: CV, Pot and the right digit of the display
15. Track mode button and LED
16. Phase/Frequency: CV and pot

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Everything in detail
Shared settings
Overall frequency control
The V/Oct input (4), FM input (3), FM knob (3), and
Frequency [F] fader (2) control the cutoff frequency in both
filter sections simultaneously. The CVs from FM and V/Oct
are added to the fader position.
The FM knob (3) has its zero level at middle setting,
indicated by a small dot. From there, turning to the right
increases the amplitude of the modulation; going to the left
increases its inverted polarity. (e.g., an LFO saw wave can
be made rising or falling as needed)
The V/Oct input (4) is reasonably following a 2F/Volt ratio;
adequate for tracking filter purposes.
In use: Bring the V/Oct signal that drives your VCO to the
Grainity V/Oct input to have tracking filtering that follows
the melody.
Overall resonance control
The Q input (6) and fader control (5) the amplitude of the
peak at the cutoff frequency point. The Q input offers a
level control pot (6) for the modulating signal.
Mix knob
This knob (7) balances the multimode VCF (full left) and
granular VCF (full right) outputs being mixed to the Mix out
(7). In addition, the Mix can be voltage controlled (7).
When pressed long, the Type/inv button (8) inverts the
signal polarity between the two filter sections. A sufficient
long press is indicated by a LED blinking.
Inversion active is indicated by dark blips on the currently
selected filter mode LED.

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The multimode VCF (M.VCF)
Filter Type
Short presses on the Type button (10) scrolls through the 6
output options of the M.VCF. (9)
The IN option is essentially used to be mixed with the G.VCF
on the Mix output. (7)
The granular VCF
Here is the signal flow of the granular filter section
Detect
Input
Zero-crossing
detection Pitch detection and tuning
Analog
Granular VCF
Matrix G.VCF
Structures
description
Filters and phase control
Selection
Track/Phase
Division Division
The whole granular engine reacts to the cycle of the incoming signal. In practice, it detects the
zero-crossing of the signal going up. This generates a flow of triggering at audio rate.
Feeding a cyclic signal from a VCO is the basic usage. It means that the filtering defined in the
structure will change at audio rate. Triggering by clocks, sequencers etc, is allowed instead of
audio. This is done via the Detect input.
The Track and Phase functions only makes sense when driven by a cyclic audio signal. The Track
function allows retuning the triggering in a musical way. Its range goes from x1 to x2.01. When
not in Track mode, the knob adjusts the Phase of the triggering stream.
The Division setting reduces the rate of the triggering.

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The triggering steps trough the currently selected Structure in a loop. Structures are definitions
of filter and phase combinations.
Cycling
Simple VCO waves have usually one zero-crossing per cycle. A 1KHz note will step the granular
engine 1000 times per second.
Some sound sources will trigger the stepping more than once per cycle. It is highly recommended
to explore that domain as it leads to unexpected and interesting results.
•Additive synthesis waves have usually several zero-crossings per cycle. Moreover, the
number of zero-crossings can change as the waves builds up with additional harmonics.
•Due to the sliding of the phase/counterphase relation in their content, Unison sounds
present a permanently evolving zero-crossing behavior.
•Synced waves present another very interesting zero-crossing triggering as they
essentially combine two fundamental tones within each global cycle.
•Ring modulator audio sources lead to highly atonal filtering in addition to their inherent
inharmony.
•Polyphonic signal (chord of a given sound) can lead to harmonically related zero-crossing
with additional cycling highly dependent of the chord content.
•Mixed sound source and percussive sounds will usually lead to chaos, which is maybe
what you need. There are ways to tame things though; see Cookbook chapter.
Detect input (12)
This input drives the granular engine in place of the audio
signal at the main input (1). This allows a number of
interesting variations. The detect jack (12) accepts audio or
any triggering/LFO signal.
Signal at Audio input
Signal to experiment at Detect input
Polyphonic sound (chord)
One of the notes from the chord - usually the lowest
Atonal sound:
•Drums
•Mixed music
•Noise
Unrelated VCO to superimpose a tone/melody to the source
Multiple zero-crossing:
•Synced waves
•Additive synthesis
Derived simple wave from the same VCO for perfect tracking by
avoiding the multiple zero-crossing at the audio input
Anything tonal or not
Noise, ring modulated source, polyphonic sound, or anything
else. This will usually mangle the signal in an aggressive way
Triggers at BPM rate from an LFO, sequencer, ...
This is used to create low-rate filter sequences

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The (phase) /Frq knob (16) and the track
button (15)
Phase mode and Track modes are exclusive and depend on
the Track button + LED (15) being on/off.
Track button off = Phase control
With the pot (16) set to minimum, the cycling of the granular filter occurs as soon as a zero-
crossing is detected. Increasing the pot delays the phase position within each cycle. The cycling
delay adjusts automatically to the frequency of the incoming signal.
Audio input
Immediate change
Phase delayed
The phase setting usually offers subtle tonal variations typical of phasing and flanging effects.
Depending on the sound source, when phase is CV modulated, it sounds similar to a unison
effect. However, there’s a difference:
•With an actual unison sound, the beating rate accelerates as the pitch of the audio signal
gets higher (twice as fast with every octave)
•With a CV modulation of the phase delay, the shifting is unrelated to the pitch
Track button (15) on = Track control
Track control is another way of applying the filter cycling on the incoming signal. Instead of using
the audio signal’s zero-crossing as is, its audio frequency is determined, then the resulting pitch is
musically (de)tuned to become the cycling trigger. For example, entering a C pitched note and
detuning it to G will cycle the granular filer 3 times over the duration of 2 audio cycles of the
incoming sound. This 3:2 ratio will follow the incoming pitch automatically.
This Tracking function can be seen as some kind of virtual VCO. However, it doesn’t create any
sound; only its cycle triggering is used to control the filtering.
The tuning Frq knob (16) goes from unison up to one octave higher with every pitch in between.
The cycling can create all kind of harmonically related pitches through filtering while benefitting
of a unison-like fine detuning.
If the detection of the zero-crossing does not allow identifying a reliable frequency, the tracking
and thus the cycling could be unpredictable. It is however suggested to use chords, unison, etc,
for interesting results.