GRP Synthesizer V22 Analog Vocoder User manual

Grp Synthesizer V22 Analog Vocoder Rev 1.3
GRP SYNTHESIZER®
V22 ANALOG VOCODER
OWNER’SMANUAL
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
CONTENTS
1. WELCOME
1.1 OPENING AND INSPECTING
1.2 FEW SIMPLE SAFETY RULES
1.3 PROPER USE
2. WHAT IS A VOCODER
2.1 ANALYSIS
2.2 SYNTHESIS
3.0 VOCODER IN ACTION
3.1 WORKING WITH SPEECH/MODULATOR SIGNAL
3.2 WORKING WITH CARRIER SIGNAL
3.3 IMPROVING QUALITY OF VOCODER SIGNAL
3.3.1 VOICED/UNVOICED SELECTION
3.3.2 ADDING SPEECH HIGH PASS SIGNAL
4. FRONT PANEL - REFERENCE
4.1 MIDI SECTION
4.2 SPEECH IN SECTION
4.3 PREAMPLIFIER SECTION
4.4 COUPLING SEZIONE
4.5 SLEW SEZIONE
4.6 VOICED/UNVOICED SEZIONE
4.7 HI PASS SEZIONE
4.8 LFO SEZIONE
4.9 MAIN OUT SEZIONE
4.10 CONNECTIONS
4.11 MIXER SEZIONE
4.12 ANALYSYS - ENVELOPE FOLLOWER OUTPUTS
4.13 SYNTESIS - VOLTAGE CONTROLLED AMPLIFIER INPUTS
5. REAR PANEL - REFERENCE
5.1 MIDI IN CONNECTOR
5.2 MIDI OUT/THRU CONNECTOR
5.3 USB CONNECTOR
5.4 DC 24V-1.66A CONNECTOR
CREDITS AND CONTACTS
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
1. WELCOME
Welcome and thank you for purchasing the Grp V22 Analog Vocoder. Your device is a refined analog Voco-
der equipped with a rich configuration of 44 analog filters -24dB/Oct for performing all the classic opera-
tions that we are used to considering indispensable in a good Vocoder and much more, guaranteeing you
years of tonal satisfaction.
1.1 OPENING AND INSPECTING
After opening the box, check inside for the presence of:
• Grp V22 Analog Vocoder.
• Dedicated external power supply.
• Cable for external power supply.
•Two metal rack ears for mounting the Vocoder into a standard 19” rack cabinet.
WARNING! To rack mount the Vocoder using the metal rack ears, it is mandatory to use the supplied
screws. If you use the screws that hold the wooden side panels in place to anchor the rack ears, you’ll
run the risk of damaging the internal electronics boards. Grp Synthesizer is not responsible for dama-
ge caused by the use of screws other than those provided and recommended.
TIP: Keep the original packaging and all its parts in case you need to ship the Vocoder.
1.2 FEW SIMPLE SAFETY RULES
GRP Synthesizer's environmental policy limits the use of polluting materials (lead, solvents, etc.) to the mi-
nimum. According to current EU legislation, it is necessary to dispose of the GRP Synthesizer V22 in accor-
dance with local regulations on the disposal of electrical and electronic waste. Under no circumstances
should you abandon the product in the environment: this action is punishable by law, as well as a long-term
source of pollution. In order to avoid the risk of electrocution and/or injuries, it is necessary to carefully fol-
low the instructions given in the manual and in the following notes.
•Do not open the Vocoder for any reason. The removal or disassembly of any panel involves exposu-
re of the operator to potentially dangerous voltages. For internal interventions, contact only Grp
Synthesizer and qualified technical personnel.
•Do not remove any screws on the external panels of the device.
•Do not expose the Vocoder to rain, water splashes, excessive humidity, steam, dust, metal particles
or any other material that can penetrate inside the ventilation holes.
•Do not insert any objects other than the appropriate plug into the rear socket of the device.
•Do not expose the device to heat sources.
•Do not expose the device to excessive vibrations or shocks during operation.
•At the time of installation or use in hot and humid rooms following storage or transport at very low
temperatures, condensation can form inside and outside the device. It is therefore essential to wait
for this condensation to disappear before turning on the device.
•Always use standard and intact power cables. In particular, never interrupt the central conductor of
the plugs or sockets that connects the metal casing to the protective earth.
•Always check that the power supply conforms to what is written on the back of the device.
•Do not obstruct the ventilation slots with which the device is equipped.
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
•In the event of severe thunderstorms, avoid using the device and disconnect it from the power sup-
ply and other equipment.
•Disconnect the device from the power supply when not in use for long periods.
•In the event of a fuse blown as a result of non-extraordinary external events, such as sudden chan-
ges or violent power outages, thunderstorms, etc., do not try to replace it, but have the device
checked by qualified technical personnel.
•Do not force the adjustment travel beyond the limits.
•Even if you are a rockstar, NEVER place containers with liquids that could spill inside it near the de-
vice.
•The device must be placed on a stable surface or, alternatively, it can be mounted in a 19 "rack ca-
binet using the two metal rack ears supplied and the two special screws for anchoring them;
do not use the screws of the wooden side panels, otherwise you run the risk of damaging the
internal electronic boards.
1.3 PROPER USE
This device is designed exclusively to produce audio frequency signals. Any other use is prohibited and
voids the Grp Synthesizer warranty. Grp Synthesizer is not responsible for damage due to improper use.
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
2. WHAT IS A VOCODER
The Vocoder is an analog circuit conceived in the first half of the last century. Its operation is based on the
possibility of adapting the harmonic and energy content of a spoken signal called Speech or Modulator to a
second electronic signal - indifferently monophonic or polyphonic - called Carrier; in this way, at the output
of the Vocoder you will be able to hear the voice message expressed by the Speech and adapted over the
Carrier that becomes “speaking". The Grp V22 is an Analog Vocoder that starts from the classic circuits of
the last century and offers an enhanced version in full compliance with analog technology.
For properly work, the Vocoder simultaneously needs two signals identified as Modulator and Carrier; the
information contained in the Modulator is used to re-equalize the harmonic content of the Carrier in real
time; the latter, according to the taste of the musician, can be a signal generated internally in the Vocoder
circuit or received from the outside world. The operations with the Modulator and Carrier signals take place
in two separate stages of processing defined as Analysis and Synthesis.
2.1 ANALYSIS
In the signal analysis phase, the Vocoder circuit extracts from the Speech/Modulator spoken signal the
energy activity present within the different frequency bands. To do this, a bank of Band Pass filters is built
whose number and center-band frequencies are properly chosen to accurately document the spoken signal
(in Grp V22 there are 22 Analysis filters covering from 185 Hz to 7040 Hz: twenty Band Pass -24dB/Oct fil-
ters comprised between a Low Pass -24dB/Oct and a High Pass -24dB/Oct.
The Modulator/Speech signal received at the microphone input, or reproduced from a previous recording,
is then analyzed by the Band Pass filters and sliced into a number of slices corresponding to the number of
available Band Pass stages: the higher the number of bands analysis, the higher the quality of the signal
produced by the Vocoder; a good size analog circuit can have from 15 to 22 analysis bands; the Grp V22
has - obviously - 22 simultaneously operative analysis bands.
The received audio signals from each of the analysis filters include any active signal portions - band by band
- within the analyzed signal; in this way, if the Speech signal contains a sibilant or a confricative, it will be
easy to find more energy in the medium-high analysis bands rather than in the low ones; a vowel “o” emit-
ted by a male baritone voice will engage mainly the low and medium-low analysis bands.
The output of each analysis filter is connected to an independent Envelope Follower module, which tran-
sforms the slice of audio signal into a control voltage whose amplitude and movement are proportional and
corresponding to the activity and energy present in the band analyzed; at the end of the Analysis stage, the
Modulator/Speech audio signal is transformed into a group of 22 parallel control voltages that document
the activity and energy distribution in the original signal.
2.2 SYNTHESIS
In the Synthesis section, a second signal called Carrier which can be indifferently monophonic or polypho-
nic, generated internally in the Vocoder or received by an external source, is subjected to the treatment of a
battery of Band Pass filters of number and frequencies in the center of the band identical to those used in
the Analysis section. In this way, the Carrier signal (which is hopefully chosen to offer a full and equally di-
stributed harmonic content, e.g. a sawtooth wave or a white noise) is sliced by 22 filtering sections which
will produce as many partial audio streams but parallel to each other. Unlike what was done in the Analysis
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
section, all 22 filters (as in the case of Grp V22) will simultaneously find full energy to process because the
Carrier source was properly chosen to offer a wide and constant range of energy activity, while the Modula-
tor signal/Speech can vary its content depending on what is said (the “message”) and the age/gender of
the speaker.
The signal slices processed by the 22 Synthesis filters are connected to the inputs of as many Amplifiers,
whose output levels are placed under the control of the 22 signals produced by the Envelope Followers of
the Analysis section; the sum of the outputs of the 22 Amplifiers is connected to a summation point (a real
Mixer) and is subsequently made available for listening at the Vocoder output. In this way, the harmonic
content of the Carrier signal is re-equalized in real time using on the harmonic content of the Modulator
Speech signal. If the latter is a male voice that counts "one, two, three and four", at the output of the Vo-
coder you will hear the Sawtooth wave oscillator used as Carrier recite "one, two, three and four" with its
own intonation (and polyphony, if available).
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
3.0 VOCODER IN ACTION
While a top level quality analog Vocoder like the Grp V22 works better than a cheaper structure, offering a
better quality signal, it is always possible to enhance the functioning of the original circuit by resorting to a
few simple behaviors.
3.1 WORKING WITH SPEECH/MODULATOR SIGNAL
To make the Vocoder circuit work as well as possible, the Speech/Modulator signal must be suitably adju-
sted to offer a signal level as homogeneous and constant as possible (it is therefore necessary to carefully
adjust the level of the microphone input signal to the circuit); for this reason, the Grp V22 features two
SPEECH IN and PREAMPLIFIER sections which offer, in addition to the volume adjustment with direct con-
trol on the Vu-meter, also COMP(ression) and NOISE GATE adjustments. It is advisable, especially during
the musical production phases, to send Speech / Modulator signals previously recorded and properly sub-
jected to level compression/normalization to the Vocoder. For live usage, it is recommended to use headset
microphones capable of maintaining a constant distance between the mouth and the microphone capsule.
3.2 WORKING WITH CARRIER SIGNAL
To engage the 22 Synthesis bands in a homogeneous way, the signal sent to them must be as rich as possi-
ble in harmonics and energy; from this point of view, a simple Sine wave is the worst choice you can make.
For this reason, analog Vocoders almost always offer one or two oscillators that produce Sawtooth and
Square waves, notoriously rich in harmonic content; Grp V22 offers an analog oscillator that produces Saw/
Square with PWM, coupled to a White Noise Generator (more details below).
The simply filtering behavior offered by the Synthesis section is indifferent to the monophonic or even poly-
phonic nature of the Carrier signal: for this reason, the most characteristic musical applications of the analog
Vocoder see equally used many full-bodied Saw/Square wave analog oscillators used to generate robotic
voices, and dense chords played on external polyphonic instruments used to generate complex harmonic
textures. As it is easy to imagine, for using of the external Carrier signal it is mandatory to recommend accu-
racy in adjusting the input level and in choosing a signal with a harmonic quality/complexity high enough to
be active on the different Synthesis bands.
3.3 IMPROVING QUALITY OF VOCODER SIGNAL
Even if today the Vocoder is considered a musical instrument for the production of Electronic Music, in the
original intentions of its inventor the most important point was the guarantee of intelligibility for the signal
produced and the possibility of recognizing what was being pronounced. For this reason, a top-quality qua-
lity analog Vocoder must provide two essential precautions: Voiced/Unvoiced selection for the Carrier signal
and the capability of recovering a variable portion of the Speech/Modulator signal processed through one
dedicated High Pass Filter.
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
3.3.1 VOICED/UNVOICED SELECTION
The Voiced/Unvoiced selection engine allows you to optimize the quality of the Carrier signal by smoothly
adapting it to the characteristics of the spoken signal received at the input of the Analysis section; when
pronouncing vowels or diphthongs, the Carrier must be sufficiently rich in acute harmonics, but must mainly
offer a good amount of energy on the frequencies normally used by human speech; when pronouncing
consonants - especially sibilants - the Carrier used must be much more active on the mid-highs. As it is not
possible to satisfy the two needs in a single carrier signal, it is necessary to automatically and safely alterna-
te two different analog signals optimized for their respective tasks: an oscillator that produces a rich tuned
waveform (Voiced portion of the Carrier signal) and a White Noise Generator that produces an energetically
rich signal of mid-high components (Unvoiced portion of the Carrier signal).
In this way, by pronouncing the word"sector", the Voiced/Unvoiced selection circuit will subject the recei-
ved Speech/Modulator signal (the word "sector") to a comparator that weighs the energy for the medium-
low portion against the medium-high portion of the signal spectrum: when there is more energy in the me-
dium-low part (the “_e__o_” sections of the word “sector”) the circuit opens for the Carrier Voiced signal
produced by the oscillator; when there is more energy in the medium-high part (the "s_ct_r" sections of the
word "sector") the circuit opens for the Carrier Unvoiced signal produced by the Noise Generator.
The transition between the two Voiced/Unvoiced components is regulated, in older projects, according to
the manufacturer's preferences; in Grp V22, it is possible to apply different transition rules (see in the Refe-
rence Section) to have very fast, fast or not-so-fast transitions applied independently in the two directions V/
UV or UV/V.
Furthermore, in Grp V22, it is possible to work with the traditional alternation SWITCHED (the two V/UV
signals are alternated mechanically by the internal circuit - the result is pleasantly robotic) or in MIXED
mode, providing for the simultaneous and miserable presence of the two V/UV components (which guaran-
tees greater fluidity, intelligibility and naturalness to the final result).
Still, in Grp V22, it is possible to disable the Voiced/Unvoiced automated selection by choosing to always
work only with the vocal portion of the Carrier Voiced signal (full bodied sound results, but without the hi-
gher average components that ensure intelligibility) or only with the noise portion of the Carrier Unvoiced
signal (useful for playing whispered voices, ghost voices, wind telling ancient horror stories, etc.).
3.3.2 ADDING SPEECH HIGH PASS SIGNAL
Even if a fairly high number of Analysis / Synthesis bands guarantees a proper intelligibility of the signal
produced by the Vocoder (with a consequent increase in the final price of the unit, sadly), the quality of
what is produced by the Vocoder can be made much clearer by mixing carefully on the output a small por-
tion of the original Speech / Modulator signal limited with a strong High Pass filtering to only the very hi-
ghest part of the harmonic spectrum. On the control panel of the Grp V22, the LEVEL control of the HI
PASS section regulates the amount of highs originally present in the Speech / Modulator signal that will be
granted in the final output of the Vocoder.
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
4. FRONT PANEL - REFERENCE
Below, the description of the controls and connections on the front panel of the device. On the Vocoder
V22 control panel there are different categories of controls: activity LEDs, knobs to rotate (controls), swit-
ches to be activated (with two or three positions), selectors for choosing a behavior, inputs and outputs.
The description proceeds section by section.
4.1 MIDI SECTION
Contains commands for MIDI behavior.
4.1.1 ACT LED
The LED lights up every time the V22 receives a MIDI messages transmitted from other devices.
4.1.2 GLIDE Control
Adjusts the Glide Time applied to the pitch of the Internal Carrier oscillator; in fully clockwise position, the
maximum Glide Time corresponds to 2.5 sec/oct.
4.1.3 MIDI TO CV Switch
In the ON position, this switch enables the pitch control of the Internal Carrier oscillator by the MIDI Note
On/Off messages transmitted from other devices. When the switch is in the OFF position, the frequency of
the internal oscillator can only be controlled with the VCO TUNE panel command and/or from the control
voltage received at the VCO 1V/OCT input port.
The Switch and the ACT LED perform multiple functions.
4.1.3.1 Setting the Vooder receiving MIDI Channel
When the Vocoder is turned on, when the MIDI TO CV switch is in the ON position, the LED starts flashing
indicating that the unit is waiting to receive any MIDI message to set the Vocoder to the MIDI channel of
the message itself. With the MIDI channel assigned, the LED stops flashing, indicating that the interface is
working properly; from that moment on, the LED works as a MIDI Activity viewer.
If the MIDI TO CV switch is in the OFF position when the Vocoder is turned on, the MIDI interface is not
activated and the LED does not flash. The internal VCO in the INTERNAL CARRIER section receives a de-
fault voltage equal to + 3V which sets its base frequency (you can change the Carrier pitch with the front
panel knob or with an external analog CV). As soon as the switch is turned ON, the LED starts flashing to
indicate the standby status of any MIDI message useful for tuning the reception channel.
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Grp Synthesizer V22 Analog Vocoder Rev 1.3
4.1.3.2 Changing receiving MIDI channel without turning off the unit
If you want to change the MIDI channel without turning off the instrument, first set the MIDI TO CV switch
to the OFF position and then move it to ON; the LED starts flashing indicating the start of the previously
highlighted MIDI reception/tuning waiting procedure.
4.1.3.3 Driving Vocoder pitch with MIDI
If you want use analog CV for control the Vocoder pitch generated by the CARRIER INTERNAL analog oscil-
lator, set the MIDI TO CV switch to the OFF position.
4.2 SPEECH IN SECTION
It contains the COMBO connector for the external Speech/Modulator signal and controls to optimize its
performance. The Speech/Modulator signal is essential for the correct operation of the Vocoder.
4.2.1 MIC/LINE INPUT Connector
The combo connector accepts XLR microphone signals or 1/4 ”TS/TRS format line signals. The signal at this
connector is used as a Speech/Modulator by the Vocoder circuit.
4.2.2 COMP Control
Clockwise adjusts the intensity of the compression applied to the input signal.
4.2.3 NOISE GATE Control
Clockwise adjusts the effectiveness of the noise reduction applied to the input signal.
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