Cwejman S1 MK2 User manual

S1 MK2 User’s Manual
(Guide/Handbook)

Table of contents page
Certification.............................................................................................. 1
Warranty and Assistance........................................................................ 1
Limitation of warranty............................................................................. 1
Before using this Synthesizer................................................................ 2
Checking Accessories....................................................................... 2
Environmental Conditions................................................................. 2
Safety Symbols..................................................................................
3
Grounding Requirements.................................................................. 3
Rack Installation................................................................................ 3
Installation of Instrument Stand (optional)......................................... 3
Repackaging for Shipment................................................................ 3
Introduction.............................................................................................. 4
Master Controller............................................................................... 6
Oscillators.......................................................................................... 9
Oscillators CV.................................................................................... 10
Mixer.................................................................................................. 11
Ring Modulator.................................................................................. 12
Noise Generator Outputs and Oscillators Outputs............................ 12
LFO.................................................................................................... 13
Low Pass Filter, Audio Input Mixer.................................................... 14
Multi Mode, Audio Input Mixer........................................................... 14
Low Pass Filter.................................................................................... 15
Multi Mode Filter................................................................................ 18
Envelope Generators......................................................................... 20
Rear Panel......................................................................................... 23
Calibration................................................................................................. 24
Oscillator scale................................................................................... 24
Master scale & Analog CV................................................................. 25
MIDI............................................................................................................ 26
Startup............................................................................................... 26
CV1 and Gate1/Trigg1....................................................................... 26
Gate2/Trigg2...................................................................................... 27
CV2.................................................................................................... 28
CV3.................................................................................................... 28
CV4.................................................................................................... 28
CV5.................................................................................................... 28
CV6.................................................................................................... 28
How MIDI Messages are Handled..................................................... 29
Program Change............................................................................... 29
Hold Pedal, Legato Pedal.................................................................. 29
All Notes-Off Message....................................................................... 29
All Sound-Off Message...................................................................... 29
Reset All Controllers Message........................................................... 29
Omni On/Off Messages...................................................................... 29
Warm up time.................................................................................... 3
Connections............................................................................................. 4
Getting started.......................................................................................... 5
Patchbay........................................................................................... 6
Master Amplifier................................................................................. 21
Oscillator range................................................................................. 25
Filters................................................................................................. 15

Reset Message Received................................................................. 29
CV Gate/Trigg Configuration............................................................. 29
Setting for CV Outputs...................................................................... 30
Setting Parameters........................................................................... 30
Routing the CV Outputs.................................................................... 31
Parameter Values, Table 1............................................................... 32
Upgrading Software.......................................................................... 33
Possible Routing of CV Outputs....................................................... 33
MIDI Implementation Chart...............................................................
Inside the Synthesizer.............................................................................
Oscillators......................................................................................... 34
Sine Waveform.................................................................................. 34
Triangle Waveform............................................................................ 35
Sawtooth Waveform.......................................................................... 35
Pulse Waveform................................................................................ 36
Triangle + Pulse Waveform............................................................... 37
Sync, Frequency and Amplitude Modulation..................................... 37
Noise generator................................................................................. 39
Ring Modulator.................................................................................. 39
Low Pass Filter................................................................................... 40
Multi Mode Filter................................................................................
Master Amplifier................................................................................. 45
Envelope Generators......................................................................... 46
33
34
44
Overdrive........................................................................................... 48
LFO.................................................................................................... 47

CERTIFICATION
Cwejman certifies that this instrument was thoroughly tested and inspected and found to
meet its published specifications when it was shipped from the factory.
WARRANTY AND ASSISTANCE
All Cwejman products are warranted against defects in materials and workmanship.
This warranty applies for 1 years from the date of delivery. We will repair or replace products,
which prove to be defective during the warranty period provided they are returned to Cwejman.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate
maintenance by buyer, unauthorized modification or misuse, accident or abnormal conditions of
operations. No other warranty is expressed or implied. Cwejman specifically disclaims the
implied warranties of merchantability and fitness for a particular purpose. Cwejman shall not
be liable for any special incidental or consequential damages, whether in contract, tort or otherwise.
Copyright 2005 by Cwejman . Printed in Sweden. All rights reserved.
No part of this manual may be reproduced in any form without written permission of Cwejman .
1

Before Using this Synthesizer
Checking Accessories
Upon receipt of this instrument, run the checks shown below:
Run visual checks against any and all damages or imperfections.
Check the quantity and rating of standard accessories to assure their conformance with
the table below.
Should there be any flaw, or damage, or missing or insufficient materials,
contact the dealer or the sales and support office.
Power cable
1
Interconnection cables, 3.5mm
6
Rack holders
2
Rack Holder screws, M5
4
The Instruction manual
1
Environmental Conditions
Do not expose this unit to direct sunlight, corrosive gas, dust or vibration. The ambient temperature
must be +15 to +30
°C and the relative humidity must not be greater than 85%. The storage
temperature of this unit is 0 to +50
°C.
This unit is designed with the affect of AC power supply line noise taken into consideration. However,
it is recommended that it be used in a place where there is minimum noise. If noise is unavoidable,
use a noise suppresser or the equivalent.
CAUTION! Before turning this unit on, check the supply voltage switch on the Rear Panel
for proper position.
Voltage selector in 115Vac position.
2
115

Safety Symbols
The WARNING sign denotes a hazard. It calls attention to a procedure, practice or the like which,
if not correctly performed or adhered to, could result in injury or loss of life. Do not proceed beyond
a WARNING sign until the indicated conditions are fully understood and met.
The CAUTION sign denotes a hazard. It calls attention to an operating procedure, practice, or the like,
which, if not correctly performed or adhered to could result in damage to or destruction of part or all of
the equipment. Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood
and met.
Grounding Requirements
The synthesizer is equipped with a three-conductor power cord which, when plugged into an appropriate
receptacle grounds the instrument. The offset pin on the power cord three-prong connector is the ground wire.
Rack Installation
This instrument can be rack mounted by using a rack mounting kit.
Rack Mounting kit; 2 brackets that are attached to the sides of the instrument by 4 M5 screws.
Installation of Instrument Stand (optional)
An instrument stand can be attached to the unit using the instrument stand kit.
Instrument stand kit: 2 stands (right, left) that are attached to the sides of the instrument by 4 M5 screws
(same screws as for rack installation).
Repackaging for Shipment
The following is a general guide for repackaging for shipment.
NOTE: If the instrument is to be shipped to Cwejman Sound for service or repair, attach a tag to the
instrument identifying the owner and indicating the service or repair to be carried out, include the serial
number. Place the instrument in its original container if available. If the original container is not available
wrap the instrument in heavy paper or plastic before placing in an inner container. Use plenty of packing
material around all sides of the instrument and protect panel faces with cardboard strips.
Place the instrument and inner container in a heavy carton or wooden box and seal with strong tape or
metal bands. Mark the shipping container DELICATE INSTRUMENT or FRAGILE.
Warm up time
After start up the unit requires 5 to 10 minutes to allow circuits to stabilise.
Specification
The following is an account of the entire unit and the technical performance of each individual module.
In addition there is a more detailed description of the characteristics of the unit's functions including
descriptions of the modules, measurements of waveforms, spectrum analysis, frequency response, etc.
3
WEIGHT 5 kg
DIMENSIONS 440mm (L), 215mm (H), 70mm (D)
POWER 115/230Vac ± 10%, 20VA

The S1 is a semi-modular, analogue monophonic synthesizer. It is easy to get started with since it is pre-
patched for optimal use of its sound producing possibilities and eliminates the need for external connections
between modules during use. Each module can be disconnected and used separately, e.g. to control or be
controlled by other instruments. This flexibility enables and simplifies experimentation with creation and
reproduction of sound.
We can mention some important features of the S1:
* Three oscillators with seven basic waveforms
* Ring modulator
* Noise generator with two three noise shapes
* Low pass filter with selectable 4 / 6 poles and quasi band pass mode
* Multi mode filter with selectable 2 to 6 poles and three modes
* Wide range envelope generators
* Master amplifier with build-in overdrive stage
* LFO with seven basic waveforms and wide rate range
* Extensive modulation of, virtually, all synthesis parameters
* Build-in MIDI to CV/gate converter with 16-bit resolution
Several parameters can be voltage controlled by external signals and, simultaneously, control external devices
by the build-in MIDI converters voltage outputs (see Rear Panel). The S1 is a stand alone instrument and the
possibility with patching and integrating it into an external modular (or semi-modular) synthesizer makes it
extremely flexible.
Introduction
4
Connections
Power; Connect the included power cable with a 115/230Vac outlet.
BEFORE YOU TURN ON THE MACHINE, BE SURE TO CHECK THE VOLTAGE SELECTOR POSITION
ON THE REAR.
AUDIO
Connect the INSTRUMENT OUTPUT of the S1 to your audio system. Use a single-ended or balanced
output cable, depending on what your audio system has to offer. For best audio performance, use the
balanced output. Please refer to your audio systems instruction for reference.
MIDI
If you want to play the S1 via MIDI, connect S1's MIDI IN to the MIDI OUT of your MIDI controller.
Select the corresponding MIDI channels on both the S1 and your MIDI controller.
All MIDI functions of the S1 are explained in detail later in this manual. Please also refer to the instructions
of your MIDI system/controller.
CV/GATE
If you want to play via CV/GATE equipped devices, please use the ANALOGUE INPUTS on the S1 rear panel.
Connect S1's CV IN to the CV OUT (1 Volt/octave) of your analogue sequencer or keyboard and connect
the GATE and/or Trigger or S-Trigger to the appropriate output of your analog controlling device.
MIDI INTERFACE MIDI IN (and programming), MIDI OUT (only program verification)
and MIDI THRU
MIDI OUTPUTS
CV1 Fixed: main pitch, 0 to 10 Volts (10 octaves)
CV2 Factory preset: Note on Velocity, 0 to 5 Volts
CV3 Factory preset: Control Change #05,
Modulation Wheel, 0 Volt ± 5 Volts
CV4 Factory preset: Channel After Touch, 0 to 5 Volts
MASTER CV CV1 incl. all controllers in the Master Controller
GATE1 +15 Volts active
TRIGG1 +15 Volts active
GATE2 +15 Volts active
TRIGG2 +15 Volts active
S-TRIG Inverted gate, short circuit active
MIDI CHANNEL MIDI channel selector
ANALOG
INPUTS
CV Main pitch, 1 Volt/ octave
GATE Envelope generator gate, 1 Volt threshold
TRIGG Envelope generator trigger, 1 Volt threshold
S-TRIG Inverted gate, short circuit active

5
CALIBRATION
OSC1, OSC2, OSC3, SCALE; 1 Volt/octave
OSC1, OSC2, OSC3, RANGE; ’RANGE’ octave steps
MASTER, SCALE; general scale sensitivity calibration
MASTER, ANALOG CV INPUT; 1 Volt/octave
MAINS INLET
Power cord inlet
115/230 V
SELECTOR
Switch for mains voltage selection
INSTRUMENT
OUTPUTS
BALANCED, 16 dBVmax @ 600 ohm (rear panel)
SINGLE ENDED, 10 dBVmax (front and rear panel)
GETTING STARTED
We guess that the first of all, you want to hear how the S1 sounds. Before you get deeper into this manual
and all the functions of the S1, please take a short tour and make yourself familiar with some of the S1 basics.
Before you power up the S1, turn down the output level knob. The S1 can produce high output levels and
you should make sure not to burn your valuable preamp, speakers or even more, your valuable ears.
FIRST power up the S1 and then turn on your audio system.
Now please bring the controls of the S1 to a simple basic setting:
You can also use this setting as an initial "reset"-patch to where you can go back to as a starting point for
new sounds.
As soon you press a key on your keyboard (or start your sequencer), you should hear the sound of a simple
bass-lead. You may also copy the picture on next page and fill in your own settings.

6
Now begin to experiment:
- Turn the FILTER MIX knob in the MASTER AMP section in position LPF or MMF to hear signals of all
oscillators.
- Change the waveforms and tunings of the oscillators.
- Change the setting of the LPF- and MMF sections (CUTOFF, Q-PEAK, POLE, MODE) and move
the FILTER MIX knob in the MASTER AMP section. See how timbres are changing?
- Turn up the CUTOFF MODULATION (CM) knobs and experiment with the ENVELOPE GENERATOR
settings to add dynamic timbre changes to the sound.
Experiment with the parameters and try to become familiar with the S1. If something might behave
unexpectedly, please be patient. All related issues will be explained in this manual and with some practice,
you will soon be able to manage the S1 and create a universe of great sounds.
Patchbay
Master Controller
The Master Controller section determinates the master frequency and/or modulation depth to all modules
coupled to it, such as oscillators and filters. The four knobs are easy to understand:
MODULATION LEVEL is pre-patched to the LFO output and determinates the master modulation depth being
aplied to the incomming pitch CV (CV1), hereby modulating all oscillators and filters connected to the master
CV bus.
GLIDE determinates the time to glide from one note to another in 5 octave span.
TRANSPOSE is the master octave setting (± 3 octaves).
FINE TUNE (± 3 semitones).
The three MASTER CV switches disconnect the corresponding
oscillator from the incomming pitch CV. The oscillators are not
tracked anymore by an e.g. keyboard, thus allowing the creation
of sounds that are not related to a tonal scale.
All oscillators FM LEVEL (controlled by knobs) are calibrated (1 Volt/octave) and can be controlled by an
external sequencer or other CV source with calibrated 1Volt/octave signal.
MODULATION INPUT sockets; the inputs for individual
frequency control of the three oscillators are internally pre-
patched to the LFO's output, OSC1's output and OSC2's
output (as you can see on the labelling of these sockets).
The LFO's output is also pre-patched to the modulation
input for the master controller.
As we mentioned before, the S1 is a semi-modular system. All modules inputs and outputs are pre-patched
and can be altered or added by the use of patch-cords. To make the use of the patching capabilities most
easy as possible, there is a specific legend used on all sockets:
- Audio and CV outputs are revealed by red surround.
- Inputs are labelled in white text.
- Where an input is pre-patched internally, its source
is labelled red in a white box. These internal patches
are bypassed as soon as you insert a plug.
Since all outputs all short circuit protected,
there is no danger to couple output to output.

7
This allows you to individually modulate the frequency of each of oscillator and the master controller just by
moving the FM LEVEL knobs in the oscillator section. The same aplied to the MODULATION LEVEL knob
in the MASTER CONTROLLER section. The MODULATION INPUT sockets breaks these pre-patched
signals and allow you to redirect any other signal to frequency control of the oscillators and the master tuning.
The MIDI CV OUTPUTS sockets provide four different control voltages generated by the internal MIDI-CV
converter of the S1, corresponding to incomming MIDI data.
The MIDI-GATES & TRIGGERS sockets provide the gate and trigger signals that are internally connected
(sent) to the envelope generators. Gate and trigger signals, generated by the internal MIDI CONVERTER are
pre-patched to these inputs and can be overriden by inserting patch-cords.
The three corresponding TRIGG & GATE switches determinate the activating of the envelope generators
to received MIDI messages and/or trigger/gate signals, selected MIDI channel (1) or selected
MIDI channel+1 (2).
The first (left) switch selects the trigger signal starting ENVELOPE GENERATOR 1 and the third switch
does the same for ENVELOPE GENERATOR 2. They choose between trigger signals (generated from note
on massages) at MIDI channel 1 or MIDI channel +1 (2) OR " no trigger" (in the middle position).
The second switch selects the MIDI channel for activating of the ENVELOPE GENERATOR 2;
selected MIDI channel (1) or selected MIDI channel+1 (2).
The MASTER CV TRACKING knobs control the cutoff frequency tracking, and allow you to set the filters
to track the master pitch CV from 0% to 200%; you can e.g. make higher notes sound brighter than lower
notes, from no effect thru calibrated 1 Volt/octave (1/1) to extreme 2 Volt/octave (2/1).
Additionally, each filter has the individual CUTOFF MODULATION switch that allows CV3 (Modulation Wheel)
or CV4 (Aftertouch) to control the cutoff frequency.

8
Master modulation level
1 millisecond to 10 seconds, 5 octave range
-3 to +3 in one octave steps
±3 semitones.
Low-Pass Filter frequency corner tuning; amount of master control voltage
0 to 2 0ctaves/Volt, detent at 1Octave/Volt
Low-Pass Filter frequency corner modulation source selector;
CV3-off-CV4, 5 Octaves range
Multi-Mode Filter frequency corner tuning; amount of master control
voltage, 0 to 2 Octaves/Volt, detent at 1Octave/ Volt
Multi-Mode Filter frequency corner modulation source selector;
CV3-off-CV4, 5 Octaves range
FREQUENCY MODULATION
Modulation inputs for Oscillators and Master Controller
Pre-patched to LFO, 1 Volt/Octave.
Pre-patched to Oscillator 1 output, 1 Volt/octave
Pre-patched to Oscillator 2 output, 1 Volt/octave
Pre-patched to LFO, 1 Volt/Octave
MASTER MODULATION LEVEL
pre-patched to LFO
ENVELOPE GENERATOR 1 SELECTOR
TRIGGER 1, main MIDI channel
TRIGGER 2, main MIDI channel + 1
MASTER CV1 CONTROL
ON/OFF SELECTOR for
OSCILLATORS 1, 2, 3
ENVELOPE GENERATOR 2 SELECTOR
GATE 1, main MIDI channel
GATE 2, main MIDI channel + 1
ENVELOPE GENERATOR 2 SELECTOR
TRIGGER 1, main MIDI channel
TRIGGER 2, mani MIDI channel + 1
FREQUENCY CONTROL INPUTS
OSCILLATOR 1, pre-patched to LFO
OSCILLATOR 2, pre-patched to OSCILLATOR 1
OSCILLATOR 3, pre-patched to OSCILLATOR 2
MIDI CONVERTER CONTROL OUTPUTS
CV1 MASTER TUNING
CV2 VELOCITY
CV3 MODULATION WHEEL
CV4 AFTER TOUCH
(factory preset)
ENVELOPE GENERATOR 1
GATE and TRIGGER
EXTERNAL INPUTS
ENVELOPE GENERATOR 2
GATE and TRIGGER
EXTERNAL INPUTS
LOWPASS FILTER CUTOFF
MODULATION
selector CV3-off-CV4
MULTI-MODE FILTER CUTOFF
MODULATION
selector CV3-off-CV4
MULTI-MODE FILTER
MASTER CV TRACKING
0 to 2 octaves/Volt
LOWPASS FILTER
MASTER CV TRACKING
0 to 2 octaves/Volt
MASTER GLIDE TIME CONTROLLER
1 millisecond to 10 seconds
MASTER TRANSPOSE
6 octaves in 1 octave steps
MASTER TUNING
± 3 semitones
MASTER CONTROL INPUT
pre-patched to LFO
MODULATION
LEVEL
GLIDE
TRANSPOSE
FINE TUNE
LPF CUTOFF
MASTER CV
TRACKING
LPF, CUTOFF
MODULATION
MMF CUTOFF
MASTER CV
TRACKING
MMF, CUTOFF
MODULATION
OSCILLATOR 1
OSCILLATOR 2
OSCILLATOR 3
MASTER
CONTROLLER
CONTROLLER

9
OSCILLATORS
The Oscillators (OSC1-3) are the main sound sources of the instrument. They are identical, except
to their pre-patched frequency modulation sources and the fact that OSC1 can be switched to LFO mode.
Oscillators are equipped with seven waveforms, sync and different frequency and pulse width modulation
routes. Given that, the oscillators offer a great flexibility in wave shaping process.
The oscillator's frequency is controlled by RANGE, TUNE, MASTER CONTROLLER and FM LEVEL.
RANGE determines the octave range of the oscillators within six octaves respective to the coarse tuning of
OSC1 in LFO-mode.
TUNE finetunes the oscillators (± 6 semitones).
FM LEVEL determinates the intensity of frequency modulation. Frequency modulation for oscillators has
different modulation sources (see table on the page 10) for a maximal modulation flexibility. Frequency
modulation, by an audio signal, creates so called "side-bands" that consist of sum and difference of signals
frequencies. These additional frequencies do mostly have a non harmonic sound. Modulation, by low periodic
waveforms, such as LFO or envelope generator creates momentary pitch shift of modulated oscillator common
named vibrato (by LFO) or pitch bend (by envelope generator).
More interesting things happen as soon as both frequencies are in the audio-range. The fast modulation
of the frequency creates so called "side-bands" that consist of sum and difference of signals frequencies.
These additional frequencies do mostly have a non harmonic sound or (with extreme modulation) noise.
Experiment first with sine waves at different frequency ranges, and then go for more complex waveforms.
SYNC means that sync'ed oscillators frequency is tracked by the frequency of controlling oscillator;
OSC3's frequency is syncronized to OSC2's frequency, OSC2's frequency is syncronized to OSC1's
frequency. When the tuned frequency of sync-ed oscillator has the same or multiple of frequency of controlling
oscillator then sync-ed oscillators waveform has no or very little "glitch" which results in a sync-ed smooth
waveform (i.e. sinus waveform). The sync-ed waveforms (with additional FM modulation) are perfect for
cutting edge lead sound and hard, funky basses.
You want to know how to trigger oscillators at zero-crossing to get most natural and static drum sounds?
Simply tune the synced oscillator to a multiple number of cycles (i.e. OSC1 = 110Hz and sync-ed
OSC2 = 880Hz). Listen to the synced oscillator only with a sine wave only and tune it, until the tone sounds
most "pure".
PULSE WIDTH % adjusts the pulse width of the pulse wave from 5% to 95%.
WAVEFORM selects the waveform or a mix of waveforms from an oscillator. PULSE WIDTH control works
also on the waveform mixes where the pulse wave is included.
The different waveforms contain different harmonic structures respective to their overtone content.
Thus they sound different from each other and can be used as raw material for creating different types
of sounds.
This is a brief description of waveforms:
*Sine contains low order harmonics with low amplitude and sounds "dull" or "pure". It's very useful for
creating of whistles, flutes and other pure sounds.
*Triangle contains more high order overtones than sine and sounds still "dull" and "pure" but with more
"edge". It is great for flutes or vibraphone-like sounds.
*Saw contains many overtones and sounds "rich" and "cutting". It is especially useful for strings,
brass and vocal-like sounds
*Pulse depends on the pulswidth. A symmetric wave (PW 50%) contains only odd harmonics and is
hollow- sounding. The more it differs from the symmetric wave, the more it sounds "edgy" and "nasal".
It is very useful for woodwind-like, pads, bass and string-like sounds.
*Mixed triangle + saw
*Mixed triangle + pulse
*Mixed saw + pulse

10
OSCILLATORS CV INPUTS
These input sockets provide the use of external signals for amplitude (AM)- and pulse width modulation (PWM).
The LEVEL inputs provide amplitude modulation. Modulation of oscillator's level (amplitude) can be provided
by any low frequency- or audio signal, such as; LFO, Envelope Generators, Oscillators or any other signal
source. If audio signals are used, the resulting waveforms are complex and contain in addition to the carrier
frequency two inharmonic sidebands per spectral component. The sound character is familiar to the results of
FM and thus useful for generating of non harmonic sounds and noises.
The PWM inputs of OSC 1 and 2 are hardwired to the outputs of the MIXER described below. The pulse width
of all three oscillators can be modulated by any other signal.
OSCILLATOR 1
RANGE
AUDIO mode 0 (C2) to 6 (C8) in 1 octave steps.
RANGE
LF mode 8 seconds to 120 milliseconds.
TUNE ±6 semitones.
PULSE WIDTH 5% to 95%.
Waveforms Sine, Triangle, Saw, Saw+Triangle, Triangle + Pulse, Saw+Pulse,
Pulse: ±5 Volts.
OSCILLATOR 2
RANGE 0 (C2) to 6 (C8) in 1 octave steps.
TUNE ±6 semitones.
PULSE WIDTH 5% to 95%.
Waveforms
SYNC Hard synchronized to Oscillator 1.
OSCILLATOR 3
RANGE 0 (C2) to 6 (C8) in 1 octave steps.
TUNE ±6 semitones.
PULSE WIDTH 5% to 95%.
Waveforms
SYNC Hard synchronized to Oscillator 2.
Sine, Triangle, Saw, Saw+Triangle, Triangle + Pulse, Saw+Pulse,
Pulse: ±5 Volts.
Sine, Triangle, Saw, Saw+Triangle, Triangle + Pulse, Saw+Pulse,
Pulse: ±5 Volts.

11
CV, LEVEL
Amplitude modulation input, ±5 Volts wave @ 5Volts input CV.
CV, PWM
Pulse width modulation input, 5% pulse width/ 1Volt input CV.
Mixer
This is a two input / two output DC-coupled mixer with input level controls. The inputs are pre-patched to the
LFO triangle wave and to the ENVELOPE GENERATOR 1, but can be coupled to any other source.
The outputs deliver the sum of the attenuated input signals and its inverted signal (sum+ and sum-). These
outputs are pre-patched to the PWM inputs of OSC1 and 2 (see above). Especially when using the LFO signal,
this can be a useful choice since the mixers outs provide the LFO signal with opposite polarity to OSC1's PWM
respective OSC2's PWM. Consequently, the oscillators pulse width sweeps in opposite directions which
results in interesting sonic possibilities.
EXT INPUT1 Pre-patched to LFO triangle output, gain = 1.
EXT INPUT2 Pre-patched to Envelope Generator 1 output, gain = 1.
S+ OUTPUT Sum of input 1 and input 2, patched to
Oscillator 1, PWM input.
S- OUTPUT Inverted sum of Input 1 and Input 2, patched to
Oscillator 2, PWM input.
MIXER OUTPUT
pre-patched to OSCILLATOR 1
PULSE WIDTH MODULATION INPUT
MIXER OUTPUT
pre-patched to OSCILLATOR 2
PULSE WIDTH MODULATION INPUT
MIXER INPUT 1
pre-patched to LFO TRIANGLE MIXER INPUT 2
pre-patched to ENVELOPE GENERATOR 1
INPUT LEVEL CONTROLS

12
Ring Modulator
A ring modulator is a classic audio effect device and due to the non harmonic character of the output signal,
very useful to create metallic timbres such as bells, sweeping whistles and percussive sounds and tremolo
effects (modulated by low periodic signal like a LFO). Two input signals are needed and pre-patched to
OSC 2 and 3 sine wave outputs. Using the EXT INPUT sockets, any other signal (internal- or external signal
source) can be routed directly into the ring modulator. The AM input enables amplitude modulation effects
(see "Mixer"). The output signal of the ring modulator is routed internally into audio mixer of the Low Pass Filter
and Multi Mode Filter. The OUTPUT socket provide the ring modulator signal for other applications.
EXT INPUTS
Inputs, pre-patched to Oscillator 2, Sine Waveform,
and Oscillator 3 (sine).
OUTPUT
Multiplier output.
LEVEL
Amplitude modulation input, 0 dB gain @ 5 Volts.
Noise Generator and Oscillators Outputs
Low frequency oscillator.
In addition to the internal routing, these output sockets provide the oscillator signals and three sorts of noise:
- WHITE noise has a balanced level of all frequencies and can be used to create wind sounds.
- RED noise contains more low frequencies and can be used to create thunder- or ocean-like sounds.
- LOW is a random low frequency signal that can be used as a modulation source to achieve sounds with
random character.
NOISE GENERATOR
White noise, red noise, low frequency noise
OSCILLATOR OUTPUTS
OSC1, OSC2, OSC3 outputs
EXTERNAL SIGNAL INPUTS
pre-patched to
OSCILLATOR 1, 2 SINUS
RING MODULATOR OUTPUT
OUTPUT LEVEL CONTROL

13
LFO, Low Frequency Oscillator
The LFO provides a sub-audio signal for modulation purposes. It is used to achieve periodic modulations
like sweeps, vibrato effects or arpeggios.
RATE determines the frequency of the LFO and is indicated by the LED
WAVEFORM SELECTOR provides seven different waveforms.
The patch-section offers some more LFO functions:
The GATE SOURCE SELECTOR switch enables the LFO to start at a zero-crossing and thus to sync
the LFO to MIDI/GATE 1, MIDI/GATE 2 or to an external signal patched to the EXT GATE socket.
Additional sockets allow the modulation of RATE and LEVEL and provide the LFO-OUTPUT.
Some interesting results can be achieved when the LFO OUTPUT is fed back to the EXT GATE input socket.
RATE 60 seconds (0.016 Hz) to 16 milliseconds (62 Hz)
Waveforms Sample&Hold random (3 speeds), triangle, sawtooth (double rate),
inverted sawtooth (double rate), square, all waveforms ±5 Volts
FM Frequency modulation input, 1 Volt/octave
LEVEL Amplitude modulation input, 0 dB gain @ 5 Volts CV
EXT GATE Synchronization to external signal (1V threshold)
or ”Gate1/Gate 2”
LFO RATE
60 seconds to 16 milliseconds
(0.016Hz to 62.5Hz)
RANDOM
SQUARE
GATE SOURCE SELECTOR
MIDI GATE1/--/GATE2
LFO OUTPUT
EXTERNAL GATE INPUT
RATE CONTROL INPUT
AMPLITUDE CONTROL INPUT
WAVEFORM
SELECTOR
RANDOM
SLEW RATE 1
RANDOM
SLEW RATE 2
TRIANGLE
INVERTED
SAW TOOTH
SAW TOOTH

14
Audio mixer for oscillator 1, 2, 3, ring modulator and pre-patched multi mode filters output.
The output signals of the three oscillators, the ring modulator and the output signal of the multimode filter has
individual levels into the lowpass filter input. The red labelling indicates the saturation level of the filter's input
stage when one source is used. Using more than one signal source, leads to earlier saturation.
The output signals of the three oscillators, the ring modulator and pre-patched white noise has individual
levels into the multi-mode filter input. The thick scale indicates the clip level of the filter's input stage when
one source is used (with higf Q-PEAK setting). Using more than one signal source, leads to earlier clip.
Low Pass Filter Audio Mixer
Multi Mode Audio Mixer
MULTI-MODEFILTER AUDIO MIXER
OSCILLATOR 1, 2, 3, RING MODULATOR
and WHITE NOISE (pre-patched)
LOWPASS FILTER AUDIO MIXER
OSCILLATOR 1, 2, 3, RING MODULATOR
and MULTI-MODE FILTER (pre-patched)

15
Filters
The most important sound shaping device of every substractive synthesizer is the filter. It cuts off specific
and adjustable frequency ranges and thus overtones, which can result in drastic sonic changes of the
filtered audio material. In the following, you will find a brief description of a filter in general, more detailed
and technical information can be found on page 38 of this manual.
We distinguish between different TYPES of filters: low pass, high pass, band pass and notch:
*
Low pass filter cuts off high frequencies and let low frequencies pass.
*
High pass filter cuts off low frequencies and let high frequencies pass.
*
Band pass filter cuts off high and low frequencies and let a more or less broad frequency bandpass.
A band pass filter is a low pass and a high pass fliter in series.
*
Notch filters do the opposite and cuts out a more or less broad frequency band out of the frequency range.
A notch filter is a low pass and a high pass in parallel.
Low pass filters are the most common used for musicial applications and you'll find two in the S1.
To gain most extensive sonic capabilities, the S1 is also equipped with a multi mode filter, that can work as
low-, high-, and band-pass (see page 42).
Next to the filter type, the slope or NUMBER OF POLES defines the characteristics of a filter.
The slope defines how steep the filter cuts off the attenuated frequency range. It is measured in dB/octave
and one pole is equivalent to 6dB/octave. That means, that the most common 4 pole low pass filter cuts high
frequencies with an attenuation of 24dB/octave and more efficient 6 pole filter cuts 36dB/octave.
The steeper the slope, the more effective the filter works (cuts overtones or undertones). Since lower slopes
also produce very musical and sonically useful results, it makes sense to implement filters with switchable
slope. The S1's filters with its two corresponding 3-slope-settings are most versatile and musically useful.
The next basic parameter is the CUTOFF-FREQUENCY or corner frequency. It defines at which frequency
the filter starts to work, respective to attenuates frequencies. On the S1, the cutoff of both filters can be
adjusted from 16Hz to 16kHz (by CUTOFF knob) and has a total frequency range from 5Hz to 30kHz.
Lets have a look on Q-PEAK. This parameter is also known as "resonance" or "emphasis". It boost the
frequencies in the range of the cutoff and makes the tone sound more "cutting". From a certain level on,
the filter starts self-oscillating and works as a sine wave oscillator.
The configuration of LPF and MMF coupled in series and/or in parallel creates a formant filter for various
vocal like sounds.
LOW PASS FILTER
The Low Pass Filter, in 4 pole mode, emulates the familiar low pass filter in some analogue synthesizer.
S1's Low Pass Filter expands sonic potential by adding a unique designed 6 pole low pass mode and quasi
band pass mode.
LPF is characterized by a non-linear transfer function, so-called saturation mode that is affected by the level
of the incoming signal. In the audio mixer the red markings on the potentiometer scales show the level at
which the filter operates in the saturation mode (For more details see LOW PASS FILTER, page 40).
The design quality of LPF's and new features makes the LPF more flexible than any other low pass filter used
in analogue synthesizers and results in qualities, such as:
*
CUTOFF, Q-PEAK and output level are voltage controlled
*
4 and 6 poles low pass mode (24 dB/octave and 36 dB/octave)
*
Qasi Band pass mode (6dB/octave high pass on low side and 24dB/octave low pass on high side)
*
Saturable; from "warm" and "smooth" sound (at low to moderate level of incoming signal)
to heavy distorted "nasty" and "aggressive" (at high level of incoming signals)
*
Ideal as "effect filter" with external sound material
*
Low noise

16
FUNCTIONS
CUTOFF controls the filters cutoff- (or corner-) frequency.
POLE selects between 4 pole low pass, quasi band pass (that sounds different than the "true" bandpass of
the MMF) and 6 pole low pass.
Q-PEAK determines the boost of the corner frequency. From "9" on, the filter starts self-oscillating.
To create useful and interesting sounds, the cutoff parameter has to be controlled dynamically.
This is mostly done by the later described envelope generators and/or by modulating the cutoff with
a periodical signal e.g. an LFO- or an audio signal. This is done with the cutoff modulation section (CM).
CUTOFF MODULATION
CM 1 adjusts the corner frequency modulation intensity by ENVELOPE GENERATOR 1.
ENVELOPE GENERATOR 1 switch inverts the control voltage of envelope generator 1.
CM 2 adjusts the corner frequency modulation intensity by ENVELOPE GENERATOR 2.
ENVELOPE GENERATOR 2 switch inverts the control voltage of envelope generator 2
OSC1/LFO adjusts the corner frequency modulation intensity by the triangle waveform of OSC1 respective
to the LFO. Maximum sweep reaching over +/-5 octaves.
OSC1 LFO switch selects the triangle waveform of OSC1 or the LFO as modulation source.
AUDIO
In the patch section of the LPF you'll find the HI Z INPUT which is an additional and patchable input.
It is internally pre-patched to the audio output of the Multi Mode Filter. This level is adjustable in the LPF
MIXER section as described above.
OUTPUT socket allows the filtered audio signal be coupled to any input. It's destinated to
the audio input of the AMP-section (FILTER MIX).
CV
Here you'll find patchable modulation-inputs for the LPF:
CUTOFF can be used to provide other signals than the triangle waveform of OSC1 or the LFO (to which it is
internally routed; see above) as a modulation source for the cutoff frequency. Use the OSC1/LFO knob to
adjust the modulation intensity.
LEVEL can be used for gain-control respectively amplitude-modulation of the LPF output signal.
Q-PEAK enables the resonance to be voltage controlled. Again, using audio signals for cv duty can provide
interesting results.