Ritual Electronics Altar User manual

Ritual Electronics
Altar

2
Summary
03................Warranty
04................Installation
05................Overview
06................Controls
07................Character
08.................Color
09................1V/Oct
10................Self patching
11................Patch ideas

3
Altar
Thank you for purchasing Ritual Electronics Altar.
Your module has been assembled with care in our
studio in Marseille, France.
You can find your module on Modulargrid:
https://www.modulargrid.net/e/ritual-electronics-altar
For any remarks and informations, contact us at:
[email protected]
For video demos and patch ideas check:
https://www.instagram.com/ritualelectronics/
https://www.youtube.com/c/ritualelectronics
Limited warranty
Ritual Electronics warrants this product to be free of defects in
materials or construction for a period of one year from the date of
purchase.
Malfunction resulting from wrong power supply voltages, backwards
or reversed eurorack bus board cable connection, abuse of the
product or any other causes determined by Ritual Electronics to be
the fault of the user are not covered by this warranty, and normal
service rates will apply.
During the warranty period, any defective products will be repaired
or replaced, at the option of Ritual Electronics, on a return-to-Ritual
Electronics basis with the customer paying the transit cost to Ritual
Electronics. The return of your module is on us.
Ritual Electronics implies and accepts no responsibility for harm to
person or apparatus caused through operation of this product.

4
Installation
Always turn your eurorack case off before plugging
or unplugging a module.
Do not touch any electrical terminals when attaching any
Eurorack bus board cable.
Ritual Electronics Altar requires:
35mA on +12V
30mA on -12V
0mA on +5V
You will need 12HP of free space in your Eurorack case to
install Altar. The module is 25mm deep.
Connect the included ribbon cable to the module. Connect the
other end of the cable to the bus board connector of your case.

5
Overview
Altar is a modern voltage controlled 3-pole, 18dB/
octave state variable filter.
The configuration of the filter can be smoothly crossfaded
from BP to LP to HP. This unusual filter type arrangement
brings out very nice harmonics and nuances. It is really
suited for CV control.
Resonance is under voltage control with attenuverter as
well allowing for great timbre modulations. It is particularly
useful to recreate accent patterns à la 303.
There is a gain at Altar’s input to beef up your signal which
then distort the filter core.
The filter tracks 1V/oct for 4-5 octaves and can turn into a
very sweet sine oscillator.
Altar is a completely original filter design by Mathieu
Fröhlich (creator of Squarp’s Hermod).

6
Frequency knob
Sets the cutoff
From sub-audio (≈2.5Hz anti clockwise)
to ultrasonic (43.5kHz fully clockwise)
Frequency attenuverter knob
Going left the CV input is subtracted
from the Frequency knob value. To the
right the CV input is added.
Resonance
Controls the resonance peak
Gain knob
Attenuate or amplify the input to
generate different filter responses
Out
Outputs filtered signal
Color & Res[onance] CV inputs
External control for each parameter
Audio input
Usually everything starts here
Color knob
Changes the state of the filter from
band-pass to low-pass to high-pass
Color & Resonance attenuverter knobs
Going left the CV input is subtracted
from the Color/Resonance knob value.
To the right the CV input is added.
Altar controls
1V/Oct
Use the 1V/Oct calibrated input for
pitch tracking
Freq[uency] CV input
External control for the filter frequency

7
Character
Patched very simply Altar is a relatively smooth
filter. It is not what you would expect from a noise
worshipping company.
If you keep the gain relatively low, crank the
resonance up a bit, you’ll find throat singing like
harmonic series hidden in the simplest square waves.
One of the filter’s quirks is the frequency range. It
goes from sub audio (2.5Hz) when all the way down
to ultra sonic (43.5kHz) when all the way up. Keep
this in mind while experimenting.
The resonance stays in control and only self oscillates
at the very last degrees of the pot. This way you can
get nuanced frequency bumps!
If you want to unlock wilder timbres, self patching
and audio rate modulations are your friends, as
usual. More on this in the following pages.
Do not underestimate the gain knob. Its neutral
position is around 2 o’clock.
This very knob changes the character of the filter
quite a lot. Specially for resonance.
Be aware that less gain can result in less than the
standard 10Vpp waveform. But it’s worth exploring
these sounds too!

8
Colors
The Color act as a three input crossfader.
It transitions smoothly from band-pass to low-pass to high-pass.
This unusual BP-LP-HP filter arrangement is very suited for voltage controlled
transition giving a more pleasant sweep than the usual LP-BP-HP.

9
1V/Oct
Altar’s 1V/Oct input allows for filter tracking and
sine oscillator functionality.
It tracks over 4-5 octaves. You can adjust the tracking
using the onboard vertical trimmer, located on the
right side of the PCB.
Calibration procedure
You’ll need a way to measure frequency. The
spectrum analyzer or tuner in your DAW can help
you if you don’t have an oscilloscope or a multimeter.
Patch a stable 1V/Oct source in the input and play
octaves. If the upper octaves are flat, turn the trimmer
clockwise. If they are sharp, turn counter clockwise.
Usually the knob fully clockwise has given the best
results!

10
Self patching
New tones can be unlocked by patching the input or
the output of the filter to its different CV inputs.
As all our modules, Altar shines when self patched.
Try patching its output in the Colour input to add
thickness to the sound.
Use multiples and stackcables and experiment!
Auto oscillation self patching trick
Altar does not provide a 10Vpp sine across the
whole frequency range when oscillating. You can
however patch the output in the input to get a higher
output. Prefer the low pass mode for such use and
ride the gain. Careful, in band-pass you can go as
high as 22Vpp using this technique!
See Patch Idea #2 on page 12 for more.

11
Patch ideas
Patch notes
Oscillator, Out Square/Saw ------------ Altar, In
Altar, out ------------ VCA, In
VCA, Out ------------ Miasma, In
Oscillator, Out Triangle ------------ Altar, Color CV
Anima, Out ----------- VCA, CV In
Anima, Out ----------- Mixer, In I
Accent gate ------------ Mixer, In II
Mixer, Out ----------- Altar, Freq CV
Accent gate ---------- Anima, Decay CV
Accent gate ----------- Resonance CV
Coarse
Fine
1V/Oct Lin FM
Exp FM PWM
Anima
Attack
Curve
Decay
_+
_+_+
_+_+_+
Attack
Curve
Decay
_+
Unipolar
Bipolar
Attack I Curve I
Out I
Out I
EOC I
EOC I
Decay I
Gate I 1V/Oct I
Attack II Curve II
Out II
Out II
EOC II
EOC II
Decay II
Gate II 1V/Oct II
_+ _+
_+
Out
Out
1V/OctFreq CVIn
Feedback
Gain
Level
Miasma
Blend
_+_+
Fdbk CV
Fdbk Out
Fdbk Out
Out
Out
InGain CV
Fdbk In
Mix
In I
In
In II
In III
O
u
t
O
ut I
O
ut III
O
ut II
Ø I
Ø II
Multiple
II
I
VCAOscillator
Out I
Out I
Out II
Out II
CV A
CV B
CV I
In I
CV II
In II
Patch #1 - 3Ø3
Using the Resonance attenuverter you can use a gate as a
resonance accent. Mix it with the cutoff enveloppe to brighten
the filter too. You can also patch it to the Decay CV of your
enveloppe to make it slightly longer as in the original machine.
Try using the triangle waveform of your oscillator to modulate
the Color CV of Altar for a slightly fizzier timbre.
Send this overly complicated mess to your favorite distortion to
finish it off.

12
Patch ideas
Patch #2 - Supersonic modulator
Use the 10Vpp self oscillation trick described page 9. From
≈3 o’clock to 5 the filter’s frequency is supersonic (20kHz to
43.5kHz). Use this to FM an other oscillator for incredible
frequency sweeps!
Pro tip: one can also use the self oscillation compensation to
have a 10Vpp emergency LFO out of Altar. It goes down to
2.5Hz. There are better uses of the filter though.
Patch notes
Altar, Out ------------ Altar, In
Altar, Out ------------ Oscillator, Lin FM In
Try using one of the oscillator’s outputs to CV the Color or Freq
on Altar for a slightly chaotic behavior
_+ _+
_+
OutOut
1V/OctFreq CV
In
Coarse
Fine
1V/Oct Lin FM
Exp FM PWM
Oscillator

13
Patch ideas
Patch #3 - Pseudo phaser
Right in between the Low Pass and High Pass lies a pseudo
All Pass filter. It doesn’t filter that much but it shifts the phase at
the cutoff point. Add in resonance to taste to hear the effect.
LFO the frequency and voilà, pseudo phaser for your Schulze
needs.
Patch notes
Anima, LFO Out ------------ Altar, Freq CV
Pay attention to the knobs positions
Anima
Attack
Curve
Decay
_+
_+_+
_+_+_+
Attack
Curve
Decay
_+
Unipolar
Bipolar
Attack I Curve I
Out I
Out I
EOC I
EOC I
Decay I
Gate I 1V/Oct I
Attack II Curve II
Out II
Out II
EOC II
EOC II
Decay II
Gate II 1V/Oct II
_+ _+
_+
Out
Out
1V/OctFreq CVIn

14
Patch ideas
Patch #4 - French filtered house
We dared. The high pass filter in Altar is sooo good you need
to try filtering your favorite disco loops and 909 beats at least
once.
Get that old sampler out or use one of the great eurorack
ones. A touch of envelope following can add to the patch.
Keep it simple, with a healthy dose of resonance to achieve
this great silky dance sound.
Cocorico.
Patch notes
Sampler, Out ------------ Envelope Follower, In
Envelope Follower, Out ---------- Altar, Freq CV
Sampler, Out ------------- Preamp, In
Preamp, Out ------------- Altar, In
Music sounds better with you
SAMPLER
Gain
In
Env Gate
Out
_+ _+
_+
OutOut
1V/OctFreq CVIn