Plankton Electronics SPICE User manual
PLANKTON ELECTRONICS
SPICE USER MANUAL
rev0
WARRANTY 3
ACKNOWLEDGMENTS 3
POWER 4
RACKING 4
FIRST STEPS 5
OVERVIEW 7
PATCHING SYSTEM 7
LED SYSTEM 8
INPUT 9
FILTER 9
DIGITAL 10
INPUT 10
FRACTIONAL BIT RATE 11
SAMPLE RATE 12
ENCODER 13
BIT MUTING 14
BIT INVERTING 14
BIT SWAPPING 14
POST FILTER 15
ANALOG 15
INPUT 15
ANALOG CIRCUITS 16
STATE VARIABLE FILTER 18
MIXER 18
FEEDBACK 19
ENVELOPE FOLLOWER 20
FINAL NOTES 21
WARRANTY
Plankton Electronics warrants this product to be free of any defect in the manufacturing
or materials for a period of one year from the date of purchase. This warranty does not
cover any damage or malfunction caused by incorrect use – such as, but not limited to,
power cables connected backwards, excessive voltage levels, or exposure to extreme
temperature or moisture levels.
The warranty covers replacement or repair, as decided by Plankton Electronics. Please,
contact our customer service for a return authorization before sending the module
([email protected]). The cost of sending a module back for servicing is
paid for by the customer.
Plankton Electronics implies and accepts no responsibility for harm to person or
apparatus caused through operation of this product.
ACKNOWLEDGMENTS
This machine has been designed by Àlex, Albert
, Miguel and Ivan for Plankton Electronics.
It has been possible thanks to the support of: Skye Klein, Aidan Taus, Uncertain
Proportions, Paul Boos, iSapien1956672, Destin LeBlanc, Daniel Browne, Casey Neiditch,
Corey Ackland, Conny Fornbäck, Brandon Ivers, jonathan scott, Olivier Ozoux, John Schussler,
eiji haruyama, Alex Brunori, Stega, Stanislav Shtin, Frédéric Folie, Aleix TVNO, Adam Lindsay,
Benedict Lee, Eldar Bikkinin, Jeroen Baekelandt, Frank Reimann, Ben D. Jones, Robert,
Swindger, Firehazrd, Ken Sheldon, Re8et, Jeffery Schenk, Greg Sterling, Daniel Browne,
SoundSweepsBy, Frieder G., James Devane, Jesús Leon, bothelbows, wtk.dwc, Philip Wise,
Nangu, Kymatica AB, Corentin Vercoustre, Martijn Pillards, Scott Silver, Rumblin Cynth
Rampo, Manu retamero, ANAL-blaster, Chris Meyer / Learning Modular, Schtickkicker, Nikki &
Madame, Lesinge, Spencer Kiss, Mike, NAOFUMI HASUIKE, Greg Cabrera, Jody Schaible, Rosa
Luxemburg, Michael Navarrette, Andrew Goodman, tgm, Mister Valentin, Frank Aponte,
Андрей Ф-П, Oliver Garcia-Borg, bpcmusic, Martin Brown, Eike, Wesley Hodgson, Martin
Daubenmerkl, Michael DeHaan, EDOUARD LOMBARD, David Eastman, Audiobender, Ian
Gowen, Aidann Bowley, Jonathan Snipes, Boyd Post, James Yanisko, Tara Stark, Nick Herman,
Saraf, Ben T. aka dyce., Jeff Farr, Rosemarijn van Westbroek, Sociopatch, G. Cantalapiedra,
Pauyl Morgan, Alexey Keller, Aziraphale, Stijn Leijte, KlemDyubua, Hiroaki Yutani, Robert
Hyman, Mark Lunney, Christopher Lutz, Nate R, Kyle, The Rosskonian, Zoundsman,
Lorenzo09, Kristoffer Larson, oliver scott, Mat Laibowitz, Hayden Nicholls, Daniel C Levler,
beat.imprint, Victor Jalencas, David LESPERON, k, Twinsun (Florent Risacher), t3hh, The
Guvnor, estemusic, Matt Lanham, Tyoma, Makeev, Apola Kipso, Jacob Carter, Roddy Graham,
Paul Deetman, Ektschn :], Clayton Grey, Peter Giles, synthfr, GDLK - Noah Murphy, Håkan Sjö
Ballina, soler, Maria Fernandez, King Heiple, Attila, Georgina, Alfredo (Can Electric), Pedro
Pina, Eloi, Befaco, Winter Modular, Endorphine.es, the Eurorack Barcelona group and many
others.
ABOUT THIS MANUAL
SPICE is modular distortion unit. It has 6 different functions that can work
independently or as a group. Think about different modules prepatched between them.
Some of the functions, like the feedback, can not be used on its own, they depend on
the other functions.
SPICE can be tricky to use. The first operation is simple. Sound destruction can be
achieved very fast by playing the controls randomly. To extract subtler effects from it, a
deeper knowledge is needed. Unless you’re an experienced user, reading this manual,
watching the Youtube videos at and reproducing the patches of the metapatch are
mandatory steps to master the machine.
Metapatch link: spice.metapatch.com
POWER
SPICE needs a 15V 1000mA DC center positive power supply. Be sure that you use the
correct power supply. Don’t mess it up!
As an eurorack module it needs 195mA on the +12V rail and 160mA on the -12V one.
RACKING
SPICE can be used in a desktop format or as a eurorack module. If you want to rack it
follow these steps:
1. Turn OFF the unit and unplug the power cable.
2. Unscrew the 4 screws on the corner.
3. Pull the unit from the case. This can be tricky. If you use a tool be careful to not
to scratch the panel. Use it only on the eurorack screw holes.
4. Disconnect the power cable from the case.
5. With the eurorack case turned OFF connect the eurorack cable to the eurorack
PSU.
6. Screw the panel to the rack.
7. Turn ON the power. Patch.
FIRST STEPS
Before reading the manual you will like to play the unit.This chapter may add some light
to the first contact with the machine.
First of all set up the unit like in the following picture. (You can also find this patch at:
http://spice.metapatch.com/patch/9492)
If you have patched it like in the picture you have to listen to some sounds now. Some
notes about this initial patch:
- Adjust the gain (“INPUT”) potentiometers on the “DIGITAL” and “ANALOG”
sections so they start to blink. If you’re using an eurorack signal they will start to
blink very quickly. With lower signals, like a guitar, you will need to turn up the
signal a lot.
- The “HP” fader must be at its lower position while the “LP” at its higher position.
This way you’re not filtering the sound.
- All the “FBACK” potentiometers must be turned down.
- The “BITRATE”, “SAMPLE RATE” and “POST FILTER” potentiometers on the
“DIGITAL” section must be fully open.
- The filter on the “ANALOG” section must be opened and on the LPF setting
(switch to the left).
Now follow this steps (go back before moving to the next step) :
- Turn down the “BITRATE” and “SAMPLE RATE” potentiometers.
- Move the “DRY” and “WET” faders and listen to the difference between the clean
and processed signals
- Select the different analog distortion circuits.
- Bypass the digital section by connecting a patch cable from the “FILTER OUT” to
the “ANALOG IN”.
- Add some resonance with the “BOOST” or “SATURATION” circuits and mix with
the result with the “DRY” signal.
- Try the different “ANALOG” filter settings (LP, BP and HP)
- Turn up the “HP” fader and see how it affect the different distortion circuits.
- Use a drum beat and connect the inverted output “INV” of the “ENV FOLLOWER”
to the the “DRIVE” CV input (turn up the attenuator).
- Repeat the above with the different CV inputs. Try the standard output “OUT” of
the “ENV FOLLOWER”.
- Patch the “ANALOG” “OUT” to one of the “CUTOFF” CV input. Turn up the
resonance.
- Invert the “ANALOG” and “DIGITAL” sections: spice.metapatch.com/patch/9489
- Turn up the “DRIVE” on the “ANALOG” section and turn up the different “FBACK”
potentiometers. At this point try these steps:
- Experiment with the different “ANALOG” circuits.
- Change the “FILTER” parameters.
- Change the gain (“INPUT”) of the “DIGITAL” and “ANALOG” sections.
Have you had fun? This is just the beginning. Let’s see how the machine works.
OVERVIEW
SPICE has different functions prepatched between them. These functions are (as
labeled in the unit):
-FILTER: a prefilter used to shape the sound being feeded to the distortion stages.
It has a high pass and a low pass filters with 2 CV inputs.
-DIGITAL: a low-fi digital section with fractional bit rate reduction, sample rate
reducing, bit muting, bit inverting, bit swapping, and a low pass filter. CV inputs
for the bit rate and sample rate functions.
-ANALOG: 7 distortion circuits followed by a resonant state variable filter. 2 CV
inputs for the “DRIVE” and the “CUTOFF” controls.
-MIXER: a two channel VCA to mix the DRY and WET signals with CV inputs.
-ENV FOLLOWER: An envelope follower with normal and inverted inputs. It takes
an audio input and convert it to an envelope.
-FBACK: a triple feedback section that takes signal of the ”WET IN” back to the
“FILTER”, the “DIGITAL” and the “ANALOG” sections.
PATCHING SYSTEM
SPICE is pre-patched (or half-normalled). This means that some inputs and outputs are
already internally connected. You can break any of these connections by connecting a
cable into the input (destination) of the half-normalled connection. By connecting a
cable at the output (source) you are splitting the signal so that output would be
available for another use while the normalled connection will remain the same.
The half-normalled routing is highlighted in the machine with the grey text. Below there
is a schematic with all the connections.
There are some internal connections (pink) that can’t be broken. These are:
- The “DRY IN”. It goes directly to “DRY” VCA of the “MIXER” section. It’s splitted to the
“MULT” output to be processed to any of the sections (or external modules).
-The whole “FBACK” section. It take the audio from the “WET IN” and sends it the input of
the “FILTER”, “DIGITAL” and “ANALOG” sections.
It’s important to understand that SPICE can be used in many different ways. The
prepatched system is just one of the possible configurations. Think about SPICE as 5
different modules that can be patched freely, independently or as whole, with or without
other modules. Think out of the box.
LED SYSTEM
There are two LED colors on SPICE. White and Pink:
White LEDs indicate a position, an state or a CV voltage. The 7 LEDs around the
encoder indicate the selected analog circuit. The LEDs on the “HP”, “LP”, “DRY”
and “WET” faders plus the “SAMPLE RATE”, “DRIVE” and “CUTOFF” ones indicate a
voltage. This voltage is the sum of the potentiometer and its related CV input.
Pink LEDs indicate an audio level. In the case of the the “ENV FOLLOWER” LED, it
indicates the audio level. This LED must blink in order to have a proper
envelope at the output. The “INPUT” LEDs at the “DIGITAL” and “ANALOG”
sections blink when the signal clips the input. They have to start to blink a little to have a
proper audio level.
INPUT
The “INPUT” section is an easy one. Usually you will connect the sound
source to the “DRY IN” connector. This will go directly to the “DRY” VCA
in the “MIXER” section. This way the DRY and WET signals can be mixed
at the end of the processing chain.
The signal is also sent to the “MULT” output. From here the signal is
seminormalled to the “ENV FOLLOWER” and the “FILTER” inputs.
An different use of this section could be: Connect the sound source to the “DIGITAL” “IN”
and then to the INPUT section. From “FILTER” “OUT” to “ANALOG” “IN”. This way you will
mix a digitized signal with it’s distorted version in the “MIXER” section.
FILTER
The “FILTER” section is formed by two 12dB filters in series. A high-pass filter and a low
pass filter plus its related CV inputs and attenuators. This section is made to provide a
prefiltering stage before the clipping sections. A proper filtering stage will determine the
desired distorted sound.
NEWBIE NOTE: “a high-pass filter (HPF) is an electronic filter that passes signals
with a frequency higher than the cutoff frequency and attenuates signals with
frequencies lower than the cutoff frequency” (Wikipedia wisdom).
A low-pass filter passes signals lower than the cutoff frequency and attenuates
signals with higher frequencies.
By default the “HP” fader will be at its lower position (about 20Hz) and the “LP” at
its top position (about 20KHz). At these positions they will not filter any sound.
The prefiltering stage is very important to get decent results at the distortion stage. It is
a basic tool to squeeze the machine and get the best of it. The most common use is to
roll off the bass frequencies before using intense distortions, like the “FUZZ” circuit. A
subtler effect is achieved by removing the high frequencies, reducing the total harmonic
content at the end of the process. This will help to fit the track in a mix.
An different use of the filter is to patch it after the “DIGITAL” or the “ANALOG” sections.
You can use it to remove some of the generated frequencies at these stages. Note the
difference between using it before and after the distortion stages.
By connecting the “INV” output of the “ENV FOLLOWER” to the “HP” CV input you will get
interesting results with drum loops. The HP will open and close according to the rhythm
of the loop. Move the fader and the CV attenuator to get the best results from it.
DIGITAL
The “DIGITAL” section is a 12 bit lo-fi audio processing where the signal is digitized and
processed in 5 different ways: fractional bit rate adjust, sample rate reducing, bit
mutting, bit swapping and bit inverting.
NEWBIE NOTE: “A digital representation expresses the audio waveform as a
sequence of symbols, usually binary numbers” (Wikipedia wisdom). Zeros and
ones. The audio signal is digitized with an analog-to-digital converter (ADC),
processed inside the microprocessor and sent back to the analog circuit through
the digital-to-analog converter (DAC).
INPUT
The input potentiometer controls the pre-amplifier stage of the “DIGITAL” section. It
must be adjusted where the clipping led starts to blink. At this point there is no clipping
yet. For eurorack signal it should be close to the zero point. For weak signals like an
electric guitar, it should be turned up.
If you’re rolling off some frequencies on the previous “FILTER” stage you will need to
readjust the “INPUT” potentiometer to get the optimal gain.
The main two functions of the “DIGITAL” section are the “BIT RATE” and the “SAMPLE
RATE”. They are accessible via the two potentiometers and its CV inputs.
FRACTIONAL BIT RATE
The bit rate is the number of bits of information on each sample. In the audio realm this
is traduced on how many steps we have to define the amplitude of the signal. A bit rate
of 1 means that there are only two states available, while a bit rate of 12 means that
there are 4096 steps.
The “BIT RATE” potentiometer and its CV input, changes the number of bits of the
digitized waveform. The 7 segment display will show how many bits are used: 1, 2, 3, 4,
5, 6, 7, 8, 9, 10 (“A”), 11 (“b”) and 12 (“C”). The dot “.” is reserved for special functions.
Usually, the systems that has the bit rate reducing feature only offer the number of
steps determined by the current bit rate. This means that for 12 bits you should have 2,
4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048 and 4096 steps available. SPICE uses a
different system called “fractional bit rate”. This means that when going from the bit 1
to the bit 2 there is a middle step (1.5) that uses 3 steps if sampling. From the bit 2 (4
steps) to the 3 (8 steps) there are several steps (5, 6, 7). And go on.
For practical reasons it makes no sense to cover all the available steps. At highest bit
rates no one can tell the difference between 1024 and 1050 steps. We kept the fractional
bit rate from the bits 1 to 8.
The 7 segment display will show only entire numbers. If the step 1.5 is selected the
display will show a “1”. Similarly, from the bit 2 to the bit 2.8 (7 steps) the display will
show a “2”.
When using the bit rate reduction function a lot of audio information will be lost.
Processing complex sounds with it will result in a noisy signal. Unless you’re looking for
extreme noise we recommend to use this feature (and the other bit features) with
purest or simplest signals that can be processed later.
An example of the above: connect a triangle wave of an oscillator directly to the digital
section. Take the output and filter into a VCF and to a VCA after that. Go back to the
SPICE and process the result with the “FILTER”, “ANALOG” and “MIXER” sections.
Demo patch: http://spice.metapatch.com/patch/9493 (“Triangle Wave Crushing”)
Do you want to add some complexity? Use the “DIGITAL” potentiometer of the “FBACK“ section to send
the result to digitized waveform and create a complex feedback loop between modules.
A variation on the previous patch could be to use the whole SPICE as (an almost) a
synth. Instead of using external VCFs, and VCAs you can use the ones on the SPICE. You
just need a basic wave and shape it with the help of external envelopes.
Demo patch: http://spice.metapatch.com/patch/9494 (“Almost a synth”)
If you have patched the previous examples you can see how SPICE can be used in many
different ways. Don’t stick to the post-processing tool!
SAMPLE RATE
Like the bit rate, the sample rate divides the audio signal in multiple samples. Each one
of this samples is represented by a value of 12 bits (or less if you have reduced the bit
rate).
At the maximum position the sample rate potentiometer will have a frequency
resolution of about 15 KHz. This resolution together wit the 12 bits makes the digital
section a lo-fi processing system. (A CD audio has a resolution of 22 KHz and 16 bit).
If you play white noise through the digital section and turn down the “SAMPLE RATE”
potentiometer, you will listen how the sample rate works very clearly.
ENCODER
Before going to the remaining digital functions we need to understand how the
encoder works. You can find this section on the “Quick Manual”:
The encoder can be used to control both the Analog and the Digital sections:
Analog
This is the initial mode (or analog mode) of the encoder. By turning it you can select one of the 7
distortion circuits of the Analog section. The internal memory of the SPICE will remember the last
selected state when the machine is powered OFF.
Digital
The digital circuit has 2 main functions: bit processing and sample rate reduction. The bit
processing includes bit rate reduction, bit muting, bit inverting and bit swapping. The bit rate will
always be selected with the potentiometer close to the 7 segment display and the “BIT RATE” CV input.
The three other available options are controlled through the encoder:
- The encoder function is set in the analog mode by default . In this mode the 7 segment display will
not blink.
- By clicking on the encoder twice (double click) you will enter the Bit Mute mode. The 7 segment will
blink. By turning the encoder knob you will be able to select the different bit numbers (from “0“ to “b”).
With a single click you will mute or un-mute each bit. A dot will appear on the muted bit. You can
mute as many bits as you want. A long click will reset the Bit Mute mode to its initial state where no
bits are muted.
- By clicking on the encoder with a double click a second time you will enter the Bit Invert mode. It
works as the Bit Mute mode. The blinking rate will be faster.
- By clicking on the encoder with a double click a third time you will enter the Bit swap mode. In this
mode you will not see numbers but different symbols. In this mode different bits will be swapped.
For example in the first step the bit number 4 will be swapped for the bit number 6. You can make as
many swaps as you want by doing a single click. A long click will completely reset the mode. The full
table of swaps can be found in the full manual.
- By clicking on the encoder with a double click a fourth time you will go back to the initial mode and
the encoder will be used to select the distortion circuits. If any of the digital modes is activated (i.e. a
bit mute at bit number 6) a dot will be displayed on the 7 segment display. By doing a long click it will
reset all the digital modes to its initial state. Turning OFF the unit will not reset the changed digital
modes.
BIT MUTING
The process of bit muting consists on muting one of the 12 bits. This means that the
muted bit will be equal to 0 no matter how is the sampled wave. Due the lost of
information the sonic result will be the addition of noise and sound artifacts.
Some notes about the bit mutting:
- The display will show which bit is to be muted. The bit “0” is the less important while the bit “b”
is the most important. This means that by muting the higher bit the audible effect will be more
dramatic.
- By muting all the bits there will be no sound at all.
- Muting the bits one by one starting from “0” and going up has the same effect as reducing the
bit rate
- Note that the bits are expressed here with its number, from “0” to “b”. In the bit rate section
the 7 segment displays shows the total number of bits used, this is from “1” to “C”.
BIT INVERTING
The process of bit inverting consists on inverting one of the 12 bits. This means that if
the inverted bit has a value of “0” it will be “1” and vice versa.
Some notes about the bit inverting:
- Like in the bit muting function, the display will show which bit is to be muted.
- By inverting all the bits there will be an inverted copy of the wave.
- The sound effect will be close the bit muting effect but with some differences.
- Note that the bits are expressed here from “0” to “b” while in the bit rate section they are
named by its natural number (from “1” to “C”).
BIT SWAPPING
The process of bit swapping consists on changing the value of one bit for the value of
another bit. If we have the 12 bit sequence “011100011111” and we have a swap
between the bits 0 and 11 the result will be “111100011110”.
The bit swapping function has 16 available swaps. You can select as many as you
can, none or all of them. The results can vary a lot from on to another.There are
more than 65.000 possible combinations.
On the next table you can see all the available swaps:
POST FILTER
Finally, after the digital process there is a simple low pass filter that can be used
to remove the high frequency content of the digital processing.
The “DIGITAL” section can add a lot of noise, specially on the high frequencies. By
removing them you can smooth the overall signal before sending it to the next
stage.
ANALOG
The “ANALOG” section is the core of SPICE. It is formed by a preamplifier, a distortion stage with
7 different analog circuits and state variable resonant filter.
INPUT
The input potentiometer controls the pre-amplifier stage of the “ANALOG” section. It
must be adjusted where the clipping led starts to blink. At this point the analog circuits
will work the best. For eurorack signal it should be close to the zero point. For weak
signals like an electric guitar, it should be turned up.
ANALOG CIRCUITS
There are 7 analog circuits:
BOOST
A clean circuit. It is used when you want to use the filter without any distortion. At high
gains it will clip the signal.
Very useful to filter the digitized signal, make some compressor like effects, or use the
feedback circuit with maximum gains.
SATURATION
A soft clip saturator. It adds a bit of harmonics to warm up your signals.
This is a classical design that uses 2 LEDs in the amplifier feedback loop to clip the signal
in a smooth and rounded shape. At low gains it will not clip.
HARD CLIP
Another classic circuit that distorts the signal but more intensely. It uses a pair of diodes
to clip the signal after the gain stage. The result is a clipped signal even at lower gains.
NU-TUBE
A tube distortion from the Korg Nu-tube vacuum fluorescent display. Amazing tube like
distortion. When the signal is distorted the light on the Nu-tube will turn off.
At lowest gains it will not distort the signal. Ideal for tube like controlled saturation.
NU-TUBE X2
Both channels of the Nu-tube for a higher gain tube distortion. At lower gains it will
distort
FUZZ
A discrete circuit based on transistors and a Germanium diode. A fuzz circuit for strong
asymmetrical clipped effects.
STOMP BOX
A filtered high gain distortion based on a very popular guitar pedal. It uses several
filters, a TL061 classic opamp and clipping diodes for a hard clip distortion.
Below there is a chart with a triangle wave processed with the different analog circuits:
The different analog circuits will not only shape the waves in a different way but
also other aspects of the audio like amplitude, frequency, and transient response.
Try different kinds of sounds with the different circuits to familiarize yourself with
all the circuits.
We recommend to skip the Digital section to learn how the Analog section works and
affect the sound. Use this simple patch to start: http://spice.metapatch.com/patch/9488
(“No Digital”)
STATE VARIABLE FILTER
The last step of the “ANALOG” section is the VCF. It is a resonant state variable filter with
low-pass, band-pass and high-pass outputs. The resonant circuit is based on the
classical SEM synth VCF.
The VCF can be used for many purposes: roll off the high end harmonics generated with
the distortion, keep only the high frequency content of a signal to enhance the DRY
signal, shape a distorted wave with an envelope, create movement with the envelope
follower, send a resonant audio to the “DIGITAL” section, etc.
A possible use of the filter is to use the “BP” to add some mid-frequency harmonics to a flat
synth signal. Instead of distorting the signal too much we add just a small amount of
saturation and sum the result to the “DRY” signal. http://spice.metapatch.com/patch/9495
(“Band Pass Spicing”).
Another possible patch may be created connecting the output of the “ANALOG” section to
the “CUTOFF” CV input. This will create a different form of feedback or X-modulation.:
http://spice.metapatch.com/patch/9496 (“Xmodulation”)
MIXER
The “MIXER” consists of two VCA channels that control the level of the “DRY IN” and “WET
IN” signals. The two signals are mixed together and are sent to the “MIXER OUT”. The
amplitude of each signal depends on the sum of the fader position and the voltage
applied at the CV input of each channel.
NEWBIE NOTE: “A variable-gain or voltage-controlled amplifier is an electronic
amplifier that varies its gain depending on a control voltage (often abbreviated CV).
VCAs have many applications, including audio level compression, synthesizers and
amplitude modulation.” (Wikipedia wisdom).
The “MIXER” section can be used in many ways. The most common way is to use it
setting a static value for each channel. But using an external envelope or the outputs
of the “ENV FOLLOWER” will give a new dimension to your sound processing
techniques.
If the desired result is a highly distorted signal, the way to go is to turn up the “WET”
fader and turn down the “DRY” one. But mixing both signals is a must if the goal is a
subtler effect.
FEEDBACK
The feedback section (labelled “FBCK”) consists of an internal routing (non breakable
and non patchable) where the signal at the “WET IN” is sent back to the input of the 3
other sections: “FILTER”, “DIGITAL” and “ANALOG”.
This situation creates audio feedback. The results are unpredictable and they will
depend on the input level at the “WET IN”, the input levels at each section, the kind of
sound used and settings at each section. Mainly it will provide some doses of chaos,
distortion and resonance.
It is very important to keep the “FBACK” potentiometers at the minimum position when
not using the function. A tiny increase on its position may affect totally the behaviour of a
whole section.
The signal sent to the “FBACK” will come from the “WET IN”. This is not relative to the
“WET” fader position, just by the signal previous to it. In a non-patched situation this
means that the output of the “ANALOG” section will be sent directly to the feedback.
ENVELOPE FOLLOWER
The envelope follower “ENV FOLLOWER” is a circuit that converts the amplitude of a
signal into an envelope. The resulting envelope is used to control the CV inputs.
The potentiometer of the “ENV FOLLOWER” sets de amplitude of the signal before being
converted to an envelope. For best results the light must blink ON and OFF.
The inverted output “INV” inverts the signal. This means that when at the “OUT” there is a
rising voltage, at the “INV” there is a falling voltage. The level at the “INV is always
negative. This means that to use it, the potentiometers related to the CV inputs must not
be at its minimum position to benefit from the “INV” envelope.
Despite of being a tiny section in the corner of the unit, the envelope follower is a
powerful function. When applied to the different CV inputs it will give movement to
the processed sound. It will make the difference between an static sound and a
dynamic one.
The “ENV FOLLOWER” input is prepatchec to the “DRY IN”. This means that it will
respond to the same signal that is being processed. But other signals different from the
input one can be used to generate envelopes. I.e.: a bass drum can generate a rhythmic
envelope which will be used to shape a synth line or a pad.
One of our most loved patches is to use the envelope follower to turn down the “DRIVE”.
This way a compressor like effect is generated. Use it with the Nu-tube distortion and a
drum loop. You can mix it with the “DYR” signal to make parallel compression.
http://spice.metapatch.com/patch/9497 (“Pump the beat”)
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