Klavis Flexshaper User manual

Klavis Flexshaper user manual V1.2 Page 1of 10
Flexshaper voltage mapper
CV-controlled voltage mapper and waveshaper
Introduction
The Flexshaper is a highly versatile module when it comes to modify evolving voltages in other
directions and levels. Five settings allow you to fold/expand/clip/compress/invert partially or
completely any CV or audio signal. The module can act as an envelope-shaping tool, frequency
multiplier, waveshaper, clipper, distortion, limiter, curve changer, and more. Five CV inputs offer
limitless control over the placement of the voltage points for dynamic signal sculpting.
Input
BipolarUnipolar
Bipolar
Flexshaper
Klavis
VC Signal Shaper
Gain
Clip
Ceiling
Mid-up
Mid-down
Halfway
Floor
Features at a glance
Process from DC to full audio range
Unipolar/bipolar input mode switch
Nominal & clip level LEDs
Output signal LED
Input gain knob for nominal level setting,
allows clean flat clipping when overdriven
Five manual voltage mapping potentiometers
Five CV control of the voltage mapping points
Simultaneously active unipolar and bipolar outputs
Firmware update via a simple audio file
Compact and skiff-friendly module

Klavis Flexshaper user manual V1.2 Page 2of 10
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!
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. (1000mA = 1
amp). 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.

Klavis Flexshaper user manual V1.2 Page 3of 10
Firmware update
If needed, the product can be updated by playing an audio file such as “Flexshaper_1.00.wav”.
Not finding any file on Klavis web product’s page means there is no update available.
Procedure
Connect a mono or stereo cable between your audio playing device headphone output
and the Flexshaper input.
Prepare to play the audio file
Set the play level of your playing device at two thirds
While pressing the Bipolar button, switch on your modular case supply
The yellow LED will flash
Start playing the audio file
If everything goes fine
The yellow LED will goes steady on
As the update is progressing, the output white LED will go brighter
When the white and green LEDs are flashing, the firmware is updated successfully
Press the button to restart the module
If the sound level is too low
The red, yellow and white LEDs will blink
Stop audio playback
Slightly increase the audio playback level
Press the button
Start audio playback from the beginning
If there is an error during the playback
The red and white LEDs will blink
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 affects the audio playback
Surrounding noisy modules, bad electrical grounding or modular supply noise

Klavis Flexshaper user manual V1.2 Page 4of 10
Birth of the product
The idea of the Flexshaper comes from a feature in the Oberheim® Matrix synthesizers called
Tracking Generator. This signal processor was part of the modulation matrix and meant to be
virtually inserted between modulation sources and destinations in order to change the shape of
the controlling signal.
The Flexshaper applies the same concept using the same 5 shaping points. However, it goes
beyond Oberheim’s implementation on two main aspects:
It goes fast enough to process signals at full audio rate
The 5 points are dynamically adjustable (CV) in real-time
Besides, the Flexshaper can process adequately bipolar and unipolar Eurorack signals.
Concept of voltage mapping
Input signal Output signal
min
max
Ceiling
Mid-up
Halfway
Mid-down
Floor
Note: actually the input and output lines should
superpose exactly; they’re here shown apart for
clarity.
Incoming voltages are divided in 4
consecutive ranges defined by 5 points. The
floor and ceiling points define the minimum
and maximum voltages processed. Voltages
beyond those limits will be considered at the
limit. Three other points are set equally
between the floor and ceiling points.
The knobs tell for each point’s default place
where the incoming voltage should go. In
other words, the knob “Halfway” defines
where a voltage entering at halfway will end
up.
When the knobs are set as shown, outgoing
voltages are replicating the incoming
voltages. The module does “nothing”. With
such default setting, we define that what
comes at the top should go at the top, and
so on for each setting point.
Unipolar and bipolar considerations
The Flexshaper handles unipolar and bipolar signals differently. To benefit from the entire control
range, it is better to select the appropriate unipolar/bipolar setting.
Whatever the input setting, both unipolar and bipolar outputs are simultaneously available. The
only differences between them are a voltage offset and the overall amplitude.
Nothing forbids you from entering a bipolar signal to use it as a unipolar result and vice-versa.
This might be useful for modulation signals such as a (bipolar) LFO you want to use as a positive
modulation only.
Here are examples of signal processing in both input modes.

Klavis Flexshaper user manual V1.2 Page 5of 10
Input signal Output signal Input signal Output signal
zero
max max +
max -
zero
Unipolar out Bipolar out
Ceiling
Mid-up
Halfway
Mid-down
Floor Floor
Mid-down
Halfway Mid-up
Ceiling
Module description
Input
Bipolar button and LED
Selects the type of signal you bring to the module. When the bipolar LED is off, you are in
unipolar input mode.
Gain button and level LEDs
To benefit from the best dynamics it is recommended to adjust the gain knob so that the green
LED goes regularly on. If you want to avoid clipping, the red LED should never go on.
NOTE about clipping
Since signals beyond the valid range are clipped, they could not be handled differently from
those reaching the top and bottom limits of the optimal range. Everything beyond a limit is
considered at the limit.
However, clipping can be done purposely in order to achieve interesting wave shaping results.
The Flexshaper clips the signal in a perfectly flat and clean way; this feature is useful to purposely
limit or flatten a signal.
Point setting knobs and CV inputs
The five setting knobs position the voltage for each level point. Default points are printed as
black dots around the pots. When the pots’ cursors match the dots, the output signal is identical
to the input signal (besides possible discrepancy due to bipolar<>unipolar in/out mismatch)
The CV inputs add up to the manual setting of the knobs. The knobs are an offset of the CV.

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Outputs and LED
Both outputs deliver the same signal with only the offset and gain being different. They can be
used simultaneously.
The bipolar output is typically used for audio signals or LFO; the unipolar output could be used for
envelopes or similar positive-only signals.
The output LED amplitude represents the unipolar signal. On the bipolar output, the LED off
represents maximum negative voltage, half brilliance is zero volt, and full bright corresponds to
maximum voltage.
Use tips
Shaping vs modulating CV signals –Setting the out level
Theoretically, the knob settings can modify a signal such as each setting point of the resulting
signal is not only at the right place among other points, but also at the right overall level.
In practice, defining the shape and out level in a single operation is difficult to do.
It is much easier to shape the signal on the Flexshaper using the full range of the pots and patch a
gain control on the output signal. Otherwise, one would have to tweak most Flexshaper pots
every time the modulation needs a gain adjustment.
What input signals give the best results?
Since the Flexshaper remaps the voltages, it is better to have signals that go through voltages
progressively and/or present several intermediate levels.
In this view, an audio square wave or gate signal are the poorest you can bring to the Flexshaper.
Given that there are only two different levels (one min and one max), all the Flexshaper can do is
change the overall level, offset and possibly polarity.
However, a simple audio/LFO triangle will allow creating various levelling effects given that a
triangle shape goes progressively through all levels between min and max.
The most interesting audio shapes to process are found in wavetable, additive synthesis, FM and
other VCOs offering shapes more complex than the ones in basic VCOs. Preprocessed or “final”
sound are also interesting audio sources.
For modulation signals, LFO’s sine and triangle are interesting enough to be remapped; even
better if they allow some waveshaping on their own. When using envelopes, non-zero attack,
decay and release times as well as a sustain level away from min or max allow more creativity.
Dynamic clipping for more waveshaping –Adding a VCA
When doing waveshaping, we suggest setting up a modulated VCA in front of the Flexshaper and
adjust the Flexshaper gain such as to clip deliberately. This will also change the relation between
the signal and the setting points which will all move at once, creating drastic changes.

Klavis Flexshaper user manual V1.2 Page 7of 10
Applications
The examples are deliberately “academic” to help you understand the logic of the system. Any
deviation from these examples and adding CV might result in more interesting results! 
Since the Flexshaper checks the various voltage levels to remap, waves with slopes tend to offer
more interesting results. This is why the examples rely on sine, sawtooth and triangle rather than
square or pulse waves.
Triangle to sine
Signal
Triangle
Mode
Bipolar
Gain
Very subtle clipping
Ceiling
Almost maximum
Mid-up
Just above default
Halfway
Default
Mid-down
Just below default
Floor
Almost minimum
Output
Bipolar
Result
Pseudo-sine
Altering the Ceiling and Floor settings inflects
the min and max voltages for a rounder shape.
A subtle touch of clipping finishes the rounding
off by shaving the top and bottom peaks.
If you can’t look at the wave on an oscilloscope
to fine tweak the settings, you can tell that you
tend to a sine wave when sounds gets softer.
Frequency doubling saw to triangle
Signal
Saw
Mode
Bipolar
Gain
Optimal (green)
Ceiling
Maximum
Mid-up
Minimum
Halfway
Maximum
Mid-down
Minimum
Floor
Maximum
Output
Bipolar
Result
Triangle 2x Freq
Alternating the settings to min and max all
along the slope creates a pair of perfectly
shaped triangles.
This processing is also useful to create a second
set of random levels behind a [sample& hold +
noise] patch doing random steps.
The derived signal will be in perfect time
relation but providing seemingly unrelated
levels.
Frequency doubling –triangle to triangle
Signal
Triangle
Mode
Bipolar
Gain
Very subtle clipping
Ceiling
Minimum
Mid-up
Mid setting
Halfway
Maximum
Mid-down
Mid setting
Floor
Mimimum
Ouput
Bipolar
Result
Triangle 2x Frq
The floor setting at the opposite of the
incoming wave makes the doubling. The two
mid knobs are put halfway to linearize the
slopes around the newly created triangle.

Klavis Flexshaper user manual V1.2 Page 8of 10
Frequency Tripling –sine/triangle to mixed wave
Signal
Sine or triangle
Mode
Bipolar
Gain
Optimal (green)
Ceiling
Maximum
Mid-up
Minimum
Halfway
Mid setting
Maximum
Mid-down
Maximum
Mid setting
Floor
Minimum
Ouput
Bipolar
Result
Mixed wave 3x Frq
By mixing slopes derived from doubling and
quadrupling we end up with a signal that
presents 3 cycles over the time of one
incoming cycle.
There are two variations with a different
timbre. By modulating the two related CVs with
inverted polarity voltages, the timbre change
can be automated.
Frequency quadrupling –triangle to triangle
Signal
Triangle
Mode
Bipolar
Gain
Optimal (green)
Ceiling
Maximum
Mid-up
Minimum
Halfway
Maximum
Mid-down
Minimum
Floor
Maximum
Ouput
Bipolar
Result
Triangle 4x Frq
Based on the Saw doubling example, both the
rising and falling slopes of the triangle will each
create two waves resulting in a triangle signal
at four times the incoming frequency.
Half wave rectifying
Signal
Any bipolar wave
Mode
Unipolar
Gain
Optimal (green)
Ceiling
Default
Mid-up
Default
Halfway
Default
Mid-down
Default
Floor
Default
Ouput
Bipolar
Result
Top of the wave
By pretending that the wave is unipolar, the
bottom half will be cut off.
The 5 settings will now apply to the remaining
positive half of the incoming signal.
On the bipolar output, the resulting signal will
be balanced around zero as a typical bipolar
wave.
Deriving a melody
When fed with the V/Oct signal from a sequencer, it is possible to remap the incoming voltages to
derive a second melodic line from the incoming one. If harmony needs be maintained, a melodic
quantizer is required.

Klavis Flexshaper user manual V1.2 Page 9of 10
Input and output can be used in unipolar or bipolar as needed.
Doubling a decaying envelope
Signal
Falling envelope
Mode
Unipolar
Gain
Optimal (green)
Ceiling
Maximum
Mid-up
Minimum
Halfway
Maximum
Mid-down
Minimum
Floor
Minimum
Ouput
Unipolar
Result
Dual falling
envelopes
This trick can be used for percussive sounds
where a single decaying envelope becomes a
pair of consecutive envelopes.
The peak level of the two envelopes can be set
independently by the Ceiling and Halfway pots.
Several variations are possible by using the 5th
pot and reassigning the role of the pots 2 to 5.
Flats (holds) or two stepped-decay are then
possible.

Klavis Flexshaper user manual V1.2 Page 10 of 10
Specifications
Mechanical
Dimensions
mm
inches
Eurorack compliance
Height
128.40
5.06
3HE
Width
30.00
1.18
6HP
Depth behind panel (without supply cable)
21.00
0.83
Supply
The supply socket is protected against reverse insertion.
Supply rail
Current draw
+12V
6 mA
-12V
7 mA
+5V
32 mA
Input/output
All inputs and outputs can withstand signals between -12V and +12V without harm.
Jack
Effective voltage range received or generated
Main input
Minimum 1V p/p for full range processing
CV control inputs
+/- 5V
Unipolar output
0 to 8V
Bipolar output
+/- 5V
Signals
Parameter
Values
Processing Frequency range
DC to 20KHz
Packing list
The box contains:
Flexshaper module
2x M3 black mounting screws + washers
Eurorack-compliant 16-pin supply cable
Quick setup notice
Klavis products, including PCB and metalwork, are designed and manufactured in Europe.