Analogue Solutions 4Voice User manual

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 1
Semblance / 4Voice user manual
english

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 2
Contents
Note About This Manual .............................................................3
SPECIFICATION...........................................................................4
INTRODUCTION...........................................................................7
APPLICATIONS............................................................................7
SAFETY INSTRUCTIONS ............................................................8
INITIAL TUNING...........................................................................9
CIRCUITS IN DETAILS.................................................................9
VCO1...........................................................................................10
VCO2...........................................................................................11
SYNC...........................................................................................12
NOISE GENERATOR..................................................................13
MIXER.........................................................................................13
VCF .............................................................................................14
Filtering External Sound Sources............................................16
ENVELOPE GENERATORS.......................................................17
EG1 ASR.....................................................................................17
EG2 ASR.........................................................................................
VCA.................................................................................................
LFO .................................................................................................
MIDI to CV CONVERTER...............................................................
EG2 ASR.....................................................................................18
VCA.............................................................................................18
LFO / Sample and Hold.............................................................19
REAR PANEL .............................................................................21
REAR PANEL DETAILS .............................................................22
REAR PANEL AUDIO CONNECTIONS .....................................23
NO SIGNAL? ..............................................................................24
QUICK METHOD FOR ZERO MODULATION............................24
EXPANSION................................................................................24
INTERNAL CALIBRATION OF VCOs........................................24
MIDI CONNECTIONS .................................................................26
LED Description.........................................................................26
Program Mode ...........................................................................26
To Set MIDI Receive Channel ...................................................27
4Voice Supplement Manual......................................................28

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 3
Note About This Manual
This manual is for the Semblance synthesiser, but includes a section for the 4Voice
version.
As the 4Voice is literally four Semblances in a rack with a few extras, it is not necc-
esary to duplicate the information. Instead we have just added an addendum to outline the
additional features of the 4voice. The main voice architechture of both are identical.
The main functional differences for the 4 voice are;
Polyphinc mode
Mono audio mixer
The main physical differences are;
13U rack mount case
Internal transformer type mains power supply.
Below; Semblance

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 4
SPECIFICATION
Brief Overview:
Semblance / 4Voice is a self contained TRUE analogue synthesiser. The voice cir-
cuitry is entirely analogue, using all discrete and op-amp components. There is no voice
DSP happening!
Semblance / 4Voice has a similar sound and specification to the classic Oberheim
SEM, but with many improvements such as MIDI, Noise, more modulation. Note however,
Semblance is not intended to be and is not a clone of the SEM. If you want a true SEM
sound, buy a SEM!
The 4Voice version has a Poly mode, to allow four the voices to be used as one big
4-voice poly synth!
Semblance / Single voice Specification;
VCO1
Fine Tune, Tune, PW Mod, FM, manual PW, Mod Source controls, Saw out, Pulse
out, Sync
VCO2
Fine Tune, Tune, PW Mod, FM, manual PW, Mod Source controls, Saw out, Pulse
out, Sync
VCF
Low pass filter, High pass filter, Band pass filter, Notch filter, variable Notch filter.
Cut-off, Resonance, ModulationAmount, Mod Source, MIDI Mod
Mixer
Audio source mixer
VCA
Mode switch, Output volume
EG1
ASR envelope with trigger LED
EG2
ASR envelope with trigger LED
LFO
Speed, Output Mode (Square, Triangle, Gate, External CV)
Noise Generator
White noise

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 5
Sample and Hold
For random modulation effects
MIDI to CV Converter
16 bit high resolution with auxiliary controller CV2 output
Many modulation possibilities.
Rotary controls:
24
Rotary switches:
6
Push button:
2
LEDs:
4
Jack sockets (6.35mm, mono);
3
MIDI Sockets;
2
Rugged steel contruction
4Voice Additional Features;
MIDI
Poly mode, to allow all 4 voices to be played as one poly synth.
Master Mixer
Mono audio mixer with master level, headphone and main output.
Intenal PSU
Internal filter mains transformer. Switchable 115V/230V.

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 6
Semblance Physical Specs;
Dimensions:
Height: 110mm Width: 242mm. Depth: 275mm
Weight:
2.3Kg
Power:
Uses external 15VAC, 500mA mains adaptor, 2.1mm DC type barrel plug.
Accessories:
Manual, Mains adaptor (230v UK or Euro type).
4Voice Physical Specs;
Dimensions:
Height: xmm Width: xmm. Depth: xmm
Weight:
xKg
Power:
115V 60hZ / 230v/50hZ, filtered internal power supply, IEC socket.
Accessories:
Manual, IEC mains lead (230v UK or Euro, or 115V USA).

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 7
INTRODUCTION
Congratulations on buying the Semblance synthesiser. Semblance is part of theAna-
logue Solutions range of analogue music equipment. Semblance is a precision electronic
musical instrument. It combines all the often needed music electronic circuitry to make a
music synthesiser in one compact module.
Nocompromisehas beenmadewith theconstructionof Semblance.Cheaperoptions
in parts have not been used;
Full rugged steel case - no plastic mouldings
Good quality smooth potentiometers, fully sealed against dust
Good quality knobs with spun aluminium caps
High grade double sided circuit board
All power and signal input/outputs have EM filters to remove external noise and im-
prove immunity
High Quality DAC - 16bit! (others use 12 or even 8 bit)
Very stable MIDI to CV conversion
Very stable analogue oscillators
Expensive blue and even more expensive white LEDs
Hand built by humans
Lasting quality and appeal with a life far longer than any software plug-in or DSP
synth
APPLICATIONS
SYNTHESISER
Semblance is for use any time you need analogue sound effects, fat basses, scream-
ing leads, beeps, tones, zaps, and all the other crazy sounds associated with analogue
synthesis. Use in place of your boring digital synths and DSP soft synths.
EFFECTS PROCESSOR
Semblance has an audio input socket, so you can feed external sounds into the on-
board analogue filters for analogue processing.

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SAFETY INSTRUCTIONS
Please read carefully before using:
• Semblance: only use the correct power adaptor - 230V (or 115V whatever your
country needs).
• 4Voice: ensure the correct voltage is selected on the bottom of the synth. 115V or
230V depending on your supply. Disconnect the power cable before changing.
• Never handle the adaptor/mains cable with wet hands
• Never excessivly bend the adaptor/mains cable or get it trapped or place heavy
objects on it. If the cable becomes damaged, replace it.
• Ensure the unit is disconnected from the mains before moving or cleaning.
• Always disconnect the unit from the mains if there is lightning in your area.
• Ensure Semblance is on a stable surface, and never place heavy objects on top of
it. The 4Voice must be rack-mounted.
• Never allow young children or animals to operate the unit or adaptor.
• Do not use excessive force when using the controls or inserting cables to the con-
nectors.
• Theunitshould notbeoperated intherain ornearwater andshouldnot beexposed
to moisture. If the unit is brought from a cold environment to a warm one, the unit should
be left to reach the ambient temperature.
• Keep the unit away from heat sources, such as radiators, ovens, heaters etc.
• Never allow the unit to get wet. Do not operate it near water, like pools, sinks, bath-
rooms etc. Do not place beverages on or near it.
• Never open the case or attempt to make repairs. Refer any servicing to a qualified
service personnel.
Preventing damage to other connected devices;
Semblance/4Voicehasaveryhighdynamicrange.Itiscapableof produceloud signals
of very high and sub-sonic frequencies that could blow inadequate speakers if played too
loud. It is recommended that input levels to external equipement (mixers, amp's etc.) is
kept low when first connected, and then sowly increased to a userable level.
Maintenance Instructions
Any cleaning of the Semblance/4Voice case should be done with a clean lint-free
cloth. DO NOT USE SOLVENTS OR CLEANERS, as this will deteriorate the exterior ap-
pearance of the equipment.
Mounting
Semblancemounting does notmean 'place onthe wall' or'to make love to' in this instance.
Place Semblance soundly on any stable surface so he cannot fall off or over, causing it
or yourself injury.
The 4Voice version should be mounted in a suitable instrument rack case (19" type). En-
sure you use all rack-mount holes.
POWER
Possible sources of US voltage mains adaptors for the Semblance (not tested);
www.radioshack.com p/n 273-1631 or 273-1690

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 9
The following sections apply to the Semblance specifically, but in gen-
eral also to the and single voice of the 4Voice too.
INITIAL TUNING
Once the MIDI and audio connections have been made it may be neccessary to tune
in the VCOs to the rest of your music set-up. Allow a five minute warm up time.
First set up the controls of Semblance to make a simple sound. It is usually best to
leave the VCA at ON. Turn VCO2 to zero volume so you can only hear VCO1.
Play, say middle C on the keyboard. Using a digital keyboard as a reference, adjust
the course or fine tuning of VCO1 until it plays in tune with your reference.
Finally, turn up VCO2 so both VCOs can be heard. Using the tune controls of VCO2,
tune it to VCO1.
CIRCUITS IN DETAILS
Here follows details on all the sockets and controls, with brief simplified explanations
of what the circuits do. We have not gone into technical details on how and exactly what
each circuit does but tried to explain each control's function and effect.
Anyone who has used synthesisers before should be familiar with the terms used and
therefore be able to predict their behaviour and how they affect the sound. The best way
to learn how to use Semblance is to go straight ahead and play with it. Reading of this
manual may only be neccessary for finer operational detail.

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VCO1
The voltage controlled oscil-
lators (VCOs 1 and 2) produce the
rawaudiowaveform usually used as
the initial source for sound creation.
Theyprovide cyclic audiowaveforms
that can be pitched. VCOs usually
receive treatment from the VCF to
turn their basic tones into pleasant
sounds.
FINE TUNE
Controlsfinepitchadjustmentof
VCO1.Use thistotuneVCO1to your
other instruments or VCO2.
TUNE
Controls the course pitch of
VCO1.Rangeisabout+/-2octaves.
Use this to tune VCO1 to your other
instrumentsor to shiftthe VCO pitch
up or down an octave compared to
the VCO2.
MODULATION
This controls the amount of modulation to either pulse width or pitch from the modula-
tion source selected by the SOURCE switch.
Turnthisknobclockwiseinincreasingamountstoapplypulsewidthmodulation(PWM)
to the square wave. This will have the affect of thickening up the VCO sound. Extreme
settings of modulation may result in the sound cutting out.
Turn this knob anti-clockwise in increasing amounts to apply frequency modulation
(FM) to VCO1. Use this for vibrato and trill effects on the pitch.
In a central position, there will be no modulation to either PW or Frequency.

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MODULATION SOURCE rotary switch
This selects the modulation source for either PWM or FM and is routed to the control
above.
The source options are;
EG1 for pitch sweeps. Good for percussion sounds
EXT1 for sound effects and additional modulation
LFO for vibrato and trill effects
VCO2 Square wave for frequency modulation effects
Select the source that you want to use to modulate PWM/FM.
PULSE WIDTH
This control allows manual shaping of the pulse wave output. It alters the pulse width
(duty cycle) of the pulse wave. In a central position a square wave is produced (50% duty
cycle). Try this control and listen to how the tone of the waveform changes. When using
Pulse Width Modulation, it is best to set the Pulse Width control to centre, otherwise the
sound may cut-out.
VCO2
FINE TUNE
Controls fine pitch adjustment of VCO2. Use this to tune VCO2 to your other instru-
ments or VCO1.
TUNE
Controls the course pitch of VCO2. Range is about +/- 2 octaves. Use this to tune
VCO2 to your other instruments or to shift the VCO pitch up or down an octave compared
to the VCO1.

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MODULATION
This controls the amount of modulation to either pulse width or pitch from the modula-
tion source selected by the SOURCE switch.
Turnthisknobclockwiseinincreasingamountstoapplypulsewidthmodulation(PWM)
to the square wave. This will have the affect of thickening up the VCO sound. Extreme
settings of modulation may result in the sound cutting out.
Turn this knob anti-clockwise in increasing amounts to apply frequency modulation
(FM) to VCO2. Use this for vibrato and trill effects on the pitch.
In a central position, there will be no modulation to either PW or Frequency.
MODULATION SOURCE rotary switch
This selects the modulation source for either PWM or FM and is routed to the control
above.
The source options are;
EG2 for pitch sweeps. Good for percussion sounds
EXT2 for sound effects and additional modulation
LFO for vibrato and trill effects
VCO1 Square wave for frequency modulation effects
Select the source that you want to use to modulate PWM/FM.
PULSE WIDTH
This control allows manual shaping of the pulse wave output. It alters the pulse width
(duty cycle) of the pulse wave. In a central position a square wave is produced (50% duty
cycle). Try this control and listen to how the tone of the waveform changes. When using
Pulse Width Modulation, it is best to set the Pulse Width control to centre, otherwise the
sound may cut-out.
SYNC
SYNC switch
This switch selects the routings for oscillator sync. The options are;
1>2 VCO2 slaved to VCO1
LFO>2 VCO2 slaved to LFO
OFF Off/no sync effect
2>1 VCO1 slaved to VCO2

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Oscillator sync is where the master signal will reset the waveform of the slave signal
each time the master waveform starts a new cycle.
Try the different settings and listen to their effect. Yo may have to modulate the pitch
of either VCO1 or VCO2 to enhance the effect.There is a balancing act between the pitch
of the two sound sources (usually the 2 VCOs) to get a good effect, once found you'll know
you've found it!
NOISE GENERATOR
Thenoisegenerator produces white noise.This is likethehiss you hear betweenradio
stations. The signal is available for filtering via the Noise/EXT1 mixer control.
Noise would be used for sound effects such as breath, wind, percussion, etc.
MIXER
The mixer is used to bring various audio source signals together for filtering. There
are 3 mixer controls;
Saw/Pulse VCO1 level
Turning the control clockwise in increasing amounts sends VCO1s pulse signal to
the mixer.
Turning the control anti-clockwise in increasing amounts sends VCO1s sawtooth
wave signal to the mixer.
In a central position no signal is sent from VCO1 to the mixer.
Saw/Pulse VCO2 level
Turning the control clockwise in increasing amounts sends VCO2s pulse wave signal

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to the mixer.
Turning the control anti-clockwise in increasing amounts sends VCO2s sawtooth
wave signal to the mixer.
In a central position no signal is sent from VCO2 to the mixer.
Noise/EXT1 level
Turning the control clockwise in increasing amounts sends the signal (if any) coming
in off the rear panel EXT1 socket to the mixer.
Turning the control anti-clock-
wise in increasing amounts sends
white Noise to the mixer.
In a central position no signal
is sent from the Noise generator or
EXT1 to the mixer.
VCF
The voltage controlled filter
(VCF) is used to alter the tone of
the VCOs/Noise and is the heart
of what gives an analogue synth its
character.
There are 4 types of filter avail-
able;Low Pass
High Pass
Band Pass
Notch Pass (variable between Low/High)
CUT-OFF
This sets the cut-off frequency, the point at which the VCF will start to filter-out har-
monics.

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RESONANCE
Resonance is a feature of adding feedback to the filter circuit. The output of the filter
is fed back into the filter input. Resonance sets the level of feedback. As the control is
increased to higher levels the filter will self-oscillate. The oscillation frequency is set by
the cut-off control.
Use Resonance to alter the tone of the filter effect. It can be used to create 'squiggy'
sounds and 'pulse hits'.
CV1/2 MODULATION amount
Turning the control clockwise will increase the amount that CV2 (MIDI controller/
velocity) will modulate the cut-off frequency.
Turning the control anti-clockwise will increase the amount that CV1 (MIDI note/pitch)
will modulate the cut-off frequency.
In a central position CV1 and CV2 will not affect cut-off modulation.
Filter Tracking (of pitch/keyboard note)
This can be achieved using CV1 (pitch) modulation of the filter cut-off as described
above.
MODULATION amount
Turning the control clockwise will increase the amount that the modulation source se-
lected by the MOD.SOURCE switch (outlined below) will modulate the cut-off frequency.
Turningthe control anti-clockwiseworks just likeclockwise except that the modulation
signal is inverted (negative).
In a central position the selected modulation source will not affect cut-off modula-
tion.
MOD.SOURCE rotary switch
This selects the modulation source that will affect the filter cut-off and is routed to the
control above.
There are 4 modulation sources;
EG1 EG1 is used as a modulation source. Use for tonal changes.
LFO The LFO is used as a modulation source. Use for filter sweeps (wah-wah).
VCO2 Pulse wave of VCO2 is used as a modulation source. Use for effects.
EXT2 Signal at the EXT2 socket is used as a mod source. Use for external filter

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 16
control.
NOTCH
This sets the relative mix between the low pass and high pass filters that is fed to the
FILTER TYPE selection switch NOTCH position (see below).
FILTER TYPE rotary switch
This selects the modulation source that will affect the filter cut-off.
There are 4 types of filter;
LOW PASS
LPF filter - signals above the cut-off frequency are attenuated 12dB/octave.
BAND PASS
BPF filter - signals above and below the cut-off frequency are attenuated 12dB/
octave.
HIGH PASS
HPF filter - signals below the cut-off frequency are attenuated 12dB/octave.
NOTCH
Notch filter - signals at the cut-off frequency are attenuated 12dB/octave.
Filtering External Sound Sources
External sound sources, such as vocals, guitars, mixer sends, samplers, etc. can be
sent through the filter for extra treatment. Note, mic's and guitars may need pre-amp'ing;
use if the signal is too quiet.
Simply plug the sound source into the rear panel EXT1 socket.
Turn the mixer control Noise/EXT1 to EXT1, and up to a suitable level.
You may wish to return the VCO1 and VCO2 mixer controls to their centre positions
so the VCOs cannot be heard.
Turn the VCA mode switch to ON. This will leave the VCA open so a constant signal
can be heard.
Finally, play around with the filter and modulation settings as neccessary.
The VCO signals can also be introduced, and use the various VCAmodes and enve-
lopes if you wish to contour the sound level and add additional effects.

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 17
ENVELOPE GENERATORS
Manual TRIGger button
Pressthis to manuallytrigger the envelopes(i.e. audition the synth).Thepitch applied
to the VCOs will be the last MIDI note received. (See MIDI for MIDI button use),
LED indicators
These will turn on each time the EGs are triggered.
EG1 ASR
EG1 is an ASR (attack / sustain / release) envelope generator. Use it to modulate
various parameters of the synthesiser. EG1 is generally assigned for use with modulating
VCO1 and the filter cut-off.
ATTACK
ControlstheAttack time.This is therate at whichthe envelope signalwill take toreach
full level when the MIDI note/key pressed.
DECAY
Controls the Decay or the Release time - the time it take the envelope signal to return
to zero when the key is released.

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 18
EG2 ASR
EG2 is just the same as EG1. EG2 is generally assigned for use with modulating
VCO2 and the VCA.
ATTACK
ControlstheAttack time.This is therate at whichthe envelope signalwill take toreach
full level when the MIDI note/key pressed.
DECAY
Controls the Decay or the Release time - the time it take the envelope signal to return
to zero when the key is released.
SUSTAIN
Controls the level the envelope will hold at when a key is pressed and the attack
cycle has completed.
VCA
The Voltage ControlledAmplifier (VCA) is the circuit
that is used to change the output volume. Normally an
envelope signal would be used to do this, so the sound
starts loud then gradually fades away. The filter audio
output is hard-wired to the VCA signal input.
MODE rotary switch
The VCA can be controlled in 4 modes;
EG2
WhenEG2 is selected, the envelope signal of EG2 is used to modulate theVCAlevel.
Use it if you require the VCA level to change over time. (Normal use).
MIDI/EG
When this is selected, EG2 is again used as the modulation source, but the overall

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 19
envelope level is in turn controlled by CV2 (MIDI). This allows velocity/controller dynam-
ics to change the volume. If CV2 source is MIDI volume (controller 7) then MIDI volume
changes can be realised.
GATE
When GATE is selected, the MIDI note on/off information is used to modulate the
VCA. With this, the VCA level is either off or full on. The audio envelope would be like an
organ's, with no attack or decay time.
ON
When ON is selected, the VCA is left permanently on at full level. Use this setting if
you wish to use the Filter as an effects processor, to process external audio fed into Sem-
blance via the EXT1 socket.
VOLUME
This sets the output volume of Semblance, i.e. the output level from the VCA that is
sent to the SIGNAL output socket.
On the 4Voice, the main output is fed directly at 1:1 level into the Master mixer. Level
adjustment of each four voices must be made using this volume control. The master mixer
has a main output level separately that controls the level of all 4 voices together (i.e. the
mixed signal).
LFO / Sample and Hold
The Low Frequency Oscillator (LFO) is basically identi-
cal to a VCO; it is another oscillator, except that it produces
periodic wave forms of low frequency, typically sub-audio.
These slow cyclic waveforms are used for modulating other
circuitparameters,forexample,for sweeping the filtercut-off
up and down, either slowly for a nice sweep, or faster for a
'wah-wah' type effect. It could be used to modulate the VCO
pitch for vibrato.
The LFO block is grouped together with the VCOs as
an LFO is an oscillator just like the VCOs are.
SPEED
This sets the frequency (speed) of the LFO.
SPEED LED indicator
This wil turn on each time the LFO signal is at a positive voltage, indicating the speed
of the LFO waveform.

analogue solutions Semblance/4Voice V2e&oe(c)21-10-2004 20
MODE
This sets the modulation source that is routed to 'LFO' points for modulation selec-
tion.
The options are;
SQUARE wave
TRIANGLE wave
MIDI control (CV2)
SAMPLE AND HOLD
Sample and Hold (S+H) is a flash term that in this instance basically means a modu-
lation is created that has a new random signal level each time the LFO completes a cycle
(each time the LFO LED lights up a new modulation level is set).