SYNTHR SYNTHR4 User manual

Le SYNTHR4
4-channel paraphonic synthesizer with MIDI control,
arpeggiator, built-in sequencer, interactive step
sequencer, modulation matrix memory, dual effects
and stereo output.

SYNTHR4 Manuel V1.06 EN
Page 2

SYNTHR4 Manuel V1.06 EN
Page 3
User Manual

SYNTHR4 Manuel V1.06 EN
Page 4
TABLE OF CONTENTS
WELCOME _____________________________________________________________________________ 5
CONNECTIONS __________________________________________________________________________ 6
WARNING______________________________________________________________________________ 6
INTRODUCTION _________________________________________________________________________ 6
FIRST VISIT_____________________________________________________________________________________________ 7
MORE DETAILS __________________________________________________________________________ 8
THE SOURCES __________________________________________________________________________________________ 8
MIXER ________________________________________________________________________________________________ 9
FILTers_______________________________________________________________________________________________ 10
MODULATIONS ________________________________________________________________________________________ 11
OUTPUTS_____________________________________________________________________________________________ 13
USE OF THE MIDI CONTROLLER____________________________________________________________ 15
THE PLAY MODES_______________________________________________________________________ 16
MONOPHONIC MODE __________________________________________________________________________________ 16
PARAPHONIC MODE____________________________________________________________________________________ 17
CHORD Mode _________________________________________________________________________________________ 17
ARPEGGIATOR Mode ___________________________________________________________________________________ 18
Step SEQUENCER Mode _________________________________________________________________________________ 19
SEQUENCER MONO Mode _______________________________________________________________________________ 20
SEQUENCER CHORD Mode_______________________________________________________________________________ 21
Mode SONG Mono _____________________________________________________________________________________ 21
SONG Chord Mode _____________________________________________________________________________________ 22
PATCHES______________________________________________________________________________ 22
PARAMETERS __________________________________________________________________________ 23
DIAPASON ____________________________________________________________________________________________ 23
GLOBAL TUNING_______________________________________________________________________________________ 23
Autotune_____________________________________________________________________________________________ 23
BRIGHTNESS __________________________________________________________________________________________ 23
POLYCHAIN ___________________________________________________________________________________________ 23
THEME_______________________________________________________________________________________________ 23
Global SYNTHR4 _______________________________________________________________________________________ 24
Global conf MIDI_______________________________________________________________________________________ 24
SYSEX________________________________________________________________________________________________ 24
ABOUT_______________________________________________________________________________________________ 25
PANIC _______________________________________________________________________________________________ 26
APPENDICES ___________________________________________________________________________ 27
APPENDIX 1 : MIDI KEYBOARD____________________________________________________________________________ 27
APPENDIX 2 : HOW TO change filtEr _______________________________________________________________________ 28
APPENDIX 3 : REAR Face_________________________________________________________________________________ 29
APPENDIX 4 : EXTERIOR MAINTENANCE ____________________________________________________________________ 29
APPENDIX 5 : HARDWARE OPTION ________________________________________________________________________ 29
APPENDIX 6 : FIRMWARE EVOLUTION______________________________________________________________________ 30
PATCHES BOOK _________________________________________________________________________________31

SYNTHR4 Manuel V1.06 EN
Page 5
WELCOME
Thank you for purchasing the SYNTHR4, and thus supporting the French electronic lutherie.
This project follows the SYNTHR3 where I wanted to push the approach by using more modern components offering more
possibilities. Jean Luc LARTIGUE ( oZoe.fr) took the opportunity to push further the ergonomics via a small color screen and
brought a higher power that you will discover along this manual. Yves USSON has been associated to this project for the
programming of the effects.
I would like to thank Laurent Cartaux for his precious help on the SYNTHR4 skin.
And I will finish my thanks for my wife and yes once again who let me have full freedom on long hours of development and
tuning.
I strongly advise you to read this manual at least once if you don't want to have a surprise like not hearing anything on the
way out.
We wish you long hours of research and music for your greatest pleasure.
https:// www.synthr.fr
Rémy WASSELIN
The presets were developed with the use of a SEM filter in channel 1 and an LP 2144 filter in channel 2 by Kurtz Mindfield
and SynthR.
They are there to guide the user who can modify them, save them to a new location. The patches when loaded call the
operating mode with which they were made. You will find some patches that call the arpeggio mode, or paraphonic mode, or
sequencer mode, in which case the corresponding sequence will be loaded as an example. It is quite possible to modify the
sound of a sequence and make another patch out of it.
See the Patches Book at the end.
The demo sequences were developed by Kurtz Mindfield.

SYNTHR4 Manuel V1.06 EN
Page 6
CONNECTIONS
Back :
•Channel 1, Channel 2 outputs: 6.35 line level jack
•CV1, CV3, outputs: corresponding to VCO1 and 3. 3.5mm jack -1V to +7V with master tune at 440Hz or -2V to +6V or
0V to 8V, impedance 1Kohm
•VCA envelope gate, VCF 2 envelope gate, outputs: 3.5mm jack 0-5V impedance 1Kohm
•Clock: 3.5mm jack TTL compatible clock available in Arpeggiator and Sequencer mode, 0-5V, 1Kohm impedance
•USB type B MIDI socket: Processor firmware update and MIDI control by software
•USB type A socket called Host to connect a USB keyboard
•MIDI Polychain Din 5 pins : Used to connect several SYNTHR4 or SYNTHR3 to increase the polyphony. Also allows to
make MIDI Out and to send a MIDI clock.
•Mains socket: IEC - 240 V AC 50Hz only, equipped with a 315mA timed fuse or 500mA fast.
Front :
•MIDI IN Din 5 pins: keyboard or sequencer input
•MIDI THRU Din 5 pins: Repeat of the MIDI IN socket.
Dimensions : 625mm*485mm*225mm
Weight : 14 kg
Power consumption : 40 VA
WARNING
Although you can open the rear panel to change a filter, it is forbidden to intervene on the power supply, as the presence of
electrical voltage can cause risks of electrocution.
Use a standard power cord.
INTRODUCTION
The SYNTHR4 is an analog synthesizer with subtractive synthesis and MIDI controls.
The VCOs of the SYNTHR4 are controlled by a processor that adjusts the frequency on demand: Autotune function.
In a historical modular synthesizer, the patches are realized by cables that link the modules together. For the SYNTHR4, no
cables, but push buttons that connect the modules together. This makes the connections between modules more readable.
These push buttons are digital switches and can therefore be stored in profiles called "Patch".
Although pre-wired, the choice of modulations remains important.
The MIDI control is done through a MIDI to CV and Gate converter which receives a MIDI master keyboard.
To take advantage of the SYNTHR4 this keyboard should have: pitch bend, modulation wheel, aftertouch and velocity and a
sustain pedal.
The MIDI converter can also be controlled by a MAO software.
The Arpeggiator part and the Sequencer part of the SYNTHR4 will be able to receive a MIDI clock and the associated "Synch
24" commands via the DIN socket.

SYNTHR4 Manuel V1.06 EN
Page 7
FIRST VISIT
SYNTHR4 consists of from left to right:
•The oscillator section consists of 4 VCOs. VCOs 1 and 3 are identical as well as VCOs 2 and 4, they will be detailed
later.
•VCOs 1 and 3 each have a SUB oscillator and a Super SAW
•A modulation section with two LFOs, the LFO1 which can be MIDI synchronized and the LFO2 with more possibilities,
both digital with 16 modifiable waveforms including a Sample and Hold and a noise generator. These LFOs can be
frequency modulated by an LFO3.
•A Ring Modulator between the different VCOs.
•A white and pink noise generator.
•An independent portamento on each VCO.
•An effects section acting on each of the 2 output channels.
•An overall MIXER that allows you to send each of the 8 available sources to the VCF1 and/or VCF2.
•Underneath are the controls of a 3rd LFO, partly controlled from the screen.
•At the bottom we find a general volume.
•The filter section with a low-pass or multimode VCF1 and a low-pass or multimode VCF2*.
•Below we find 2 VCAs with automatic panning or not.
•3 envelope generators, one of which is used as a modulation for the VCOs and the LFO1, one for the VCFs and one
for the VCAs.
We have done the tour of the analog part and we arrive on the controller with its graphic screen which will allow us to
control the various modes of play, the MIDI channel if necessary, the Tuning fork, to save "patches" and to activate the
internal Arpeggiator as well as the Sequencers and many other settings. Equipped with seven buttons and a rotary encoder,
this controller allows all possible actions of the synthesizer. It has no effect on the audio synthesis.

SYNTHR4 Manuel V1.06 EN
Page 8
MORE DETAILS
THE SOURCES
The VCOs are based on the SSI2130 circuit of great integration which naturally offers a very good slope of 1V/octave over
several octaves. However, this synthesizer is equipped with an Autotune which allows to keep its accuracy on the tessitura.
VCO1 AND VCO3:
•Octave selector on + or - 2 octaves, by successive presses.
•Fine tuning on + or - 2 semitones to + or - 12 semitones, (configurable in the Settings
menu).
•Keyboard tracking via MIDI to CV including the pitch wheel of + or - 1 tone
(configurable in the Settings menu).
•Adjustment of the SuperSAW *intensity in the SAW. Potentiometer at 0 : Standard
Saw.
•Adjustment of the pulse width (PW) 10 to 90%.
•Frequency modulation by :
•Adjustable input 1: LFO1 or Modulation Envelope or Aftertouch (if the keyboard
delivers it).
•Adjustable input 2 : LFO2 or VCO2 (Cross modulation).
•Pulse Width Modulation (PWM):
•Adjustable input 1: LFO1 or Modulation Envelope.
•Adjustable input 2: LFO2 or VCO2 (Cross modulation)
•Simultaneous outputs possible : Sine, Triangle, Sawtooth, Pulse
* SuperSAW is an addition of original saw plus one saw moving at 0.1 Hz plus second one
animated by LFO2 if On
VCO2 AND VCO4:
▪Octave selector on + or - 2 octaves,
▪Fine tuning on + or - 2 semitones to + or - 12 semitones, (configurable in the Settings menu).
▪Keyboard tracking via MIDI to CV including the pitch wheel of + or - 1 tone (configurable in the Parameters menu).
▪Synchronization of VCO2 on VCO1 and VCO4 on VCO3
▪Adjustment of the pulse width (PW) 10 to 90%.
•Frequency modulation by :
•Adjustable input 1: LFO1 or Modulation Envelope or Aftertouch (if the keyboard delivers it).
•Adjustable input 2 : LFO2 or VCO2 (Cross modulation).
•Pulse Width Modulation (PWM):
•Adjustable input 1: LFO1 or Modulation Envelope.
•Adjustable input 2: LFO2 or VCO2 (Cross modulation)
•Continuously variable output: Triangle, Sawtooth, Pulse that can be controlled by the LFO2 or the modulation
envelope.
To perfect your knowledge of VCOs you can view the tutorial N°1, VCO at: Médias | SynthR or SynthR4 - Tuto 1
: Les VCO - YouTube

SYNTHR4 Manuel V1.06 EN
Page 9
SUB1 AND SUB2 :
•Output at octave -1 of VCO1 and VCO3: Triangle, Sawtooth, Square
•Output at octave -2 of VCO1 and VCO3: Square
NOISE
•White noise
•Pink noise .
RING MODULATOR
•Between VCO1 and VCO2 or VCO4 measurable or between VCO3 and VCO2 or
VCO4.
See tutorial N°3 for this section: Médias | SynthR or SynthR4 - Tuto 3 : Le reste de la façade gauche - YouTube
MIXER
•Each of the above sources can be sent to VCF1 and/or the VCF2.
If no VCF1 or VCF2 destination is engaged, there will be no output sound.
Depending on the game modes chosen, choices will be indicated and sometimes not
modifiable.
After pressing the " SHIFT " key below the screen, the VCF1 and VCF2 assignment buttons
change their role and become note activation buttons of the Step sequencer, as we shall
see later.

SYNTHR4 Manuel V1.06 EN
Page 10
FILTERS
The VCFs are either discrete circuits or integrated circuits (like the AS3320 or the SSI2144) using known schematics, but in no
case will they be clones of the components. It is therefore possible that some people will not find the grain, the fineness, the
harmonic range or even the known defects of these famous filters.
VCF1 AND VCF2:
Suggested choices see Appendix 2.
•Cutoff
•Resonance
•Keyboard tracking 0 to 120%. The 100% is between 8 and 9.
•Dedicated Envelope input
•Adjustable modulation input 1 : LFO1 or LFO2 or VCO1.
•Adjustable modulation input 2 : Aftertouch or Modulation wheel
•Low Pass, Band Pass, High Pass selection for multimodes only
From one filter to another, the cutoff and resonance potentiometers can have different
behaviors, especially at the end of the run.
- When a Low-Pass only filter is inserted the BP and HP buttons are inactive
- For some multimode filters, the mixing of modes is possible, for example LP and HP. This is valid for the so-called
SVF or state variable filters. Other multimode filter will not allow this mixing.