Voyager Old School
User’s Manual
Table of Contents
FORWARD from Mike Adams ..................................
How to use this Manual .......................................
Setup and Connections ........................................
Overview and Features ........................................
Signal Flow ....................................................................
A. Mixer Section ........................................................
B. Oscillator Section ................................................
C. Filter Section .........................................................
D. Envelopes Section ..............................................
E. Output Section .....................................................
F. Modulation Section ..........................................
G. LFO Section .........................................................
H. Keyboard & LH Controllers .........................
I. Back Panel ..................................................................
A – Specifications .................................................................
B – VX-351 CV Expander ..............................................
C – Using the CP-251 with the Voyager .................
D – Synthesis Tutorial .........................................................
E – Service & Support Information ...........................
F – Caring for the Voyager Old School ...................
G – Accessories ...................................................................
GLOSSARY .......................................................................................
PATCH TEMPLATES .....................................................................
Page 3
Congratulations! You now own the Minimoog Voyager Old School, a successor to the synthesizer that Sonic State named the
number one synth of all time: the Minimoog Model D. A descendant of the original Minimoog, the Voyager Old School is an
‘instant classic’ that is destined to become another revered piece of synthesizer history, and it is truly yours!
We are so pleased to bring this product to you, and expect it to give you a lifetime of musical satisfaction. Of course, all
of the credit goes to Bob Moog, to whose specifications we still build instruments everyday. The release of the Voyager
Old School synthesizer pays homage to Bob as well as to the classic Model D Minimoog. The Old School has the analog
sound engine of the original Voyager, but without the digital elements of patch storage and MIDI control. It recaptures the
directness and simplicity of the Model D, but adds extended modulation and Control Voltage interface capabilities. If you
are a long time Minimoog player or have always wanted an original Model D, the Voyager Old School is the perfect solution
for you. For those looking for a full-featured centerpiece for their modular synth rig or for anyone craving a direct, hands-on
connection to their musical creativity, I believe you will find all of that and more with this exciting new product.
Before you power up and start exploring your new Voyager Old School, let me offer two brief reminders. First, please
register your beautiful new instrument via the Moog Music web site (alternatively you can mail in the
included warranty card), and let us know what you think in the ‘Comments’ section. We value every response that comes
to us through our warranty registration program. Second, start playing! And once you do, promise yourself you will go back
and read this User’s Manual. It was created to give you a complete understanding of how the Voyager Old School operates
and offers helpful suggestions for getting the most from the instrument.
Finally, thank you for sharing your hard earned dollars, euros, sterling, or rupiahs with us. We never take that for granted
and we want to encourage you to contact us for any reason - hopefully it will be to simply say “I love this machine.”
And, if you are ever near Asheville, N.C. USA, please come by the Moog factory. We’d love to see you!
Warm Regards,
Mike Adams
President, Moog Music, Inc.
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Voyager OS User’s Manual - The Basics
How to Use this Manual
This User’s Manual is organized into convenient sections to assist you in setting up, playing and exploring
your new Voyager OS.
The Setup and Connections section explains how to unpack, setup and connect the Voyager OS, and provides
a quick start to get you up and running with your new instrument.
The Components section offers detailed explanations of the Voyager OS components that create and modify
The Appendix provides additional information, such as technical specifications, service and support info, and
making connections to optional external equipment. First time users should read Appendix D, Synthesis
Tutorial, where you will find an explanation of sound and subtractive synthesis.
At the back of the manual, you’ll find a Glossary that defines important synthesizer terminology, and several
Patch Template pages for programming and documenting your favorite sounds.
Throughout the manual you will see icons that offer additional information. Here’s what they mean:
This icon indicates an important note concerning the operation of the Voyager.
This icon indicates a useful performance or programming tip.
This icon indicates technical information for the advanced user or the technically curious.
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Voyager OS User’s Manual - The Basics
Setup and Connections
In a perfect world, everyone would read the User’s Manual from cover to cover before connecting and
playing their new instrument. For those of you who don’t live in a perfect world and can’t wait to play your
new synthesizer (completely understandable), the following should get you set up and running quickly.
Note: You are encouraged to read the entire manual at some point to learn more about the
instrument and gain a better understanding of what you can do with the Voyager.
Check the contents in the shipping carton
The Voyager is shipped with the following items:
1. The Voyager OS Synthesizer
2. Power cord
3. User’s Manual
4. Warranty registration card
What you will need
In addition to the Voyager and provided accessories, you will need:
1. A stand or table sufficient to support the Voyager OS
2. A 1⁄4” instrument cable (for mono) or two 1/4” instrument cables (for stereo) and an
amplifier, or a pair of headphones
3. A properly wired AC outlet.
Set up
Make sure you have an adequate place to set it up. You will need a sturdy keyboard stand or flat surface
that will provide the proper support (the Voyager Old School weighs approximately 40 lbs.) and will not
easily topple. Use caution when lifting the Voyager out of the carton, and be sure to save the carton and all
packing material in case you need to ship the Voyager for any reason.
Connect to Power and Amplifier
Make the connections as shown below. Connect the Voyager’s power receptacle (on the back panel) to
a wall outlet using the supplied AC power cord. The Voyager’s universal power supply will operate with
a power source from 90 to 250 Volts AC, 50/60Hz. Do not switch on the power yet. Set the Voyager’s
Master Volume control to minimum before making the connection to an amplifier or headphones.
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Voyager OS User’s Manual - The Basics
Now Power up
Turn the Voyager OS power ON. The LFO RATE LED will be begin to blink at the rate set by LFO RATE
knob, indicating that the Voyager OS is ON.
Test for Sound and Set Levels
Play a few notes on the Voyager OS keyboard while turning up the volume of your amplification. Set the
volume to a comfortable listening level.
Start Playing
The sound produced by the Voyager OS is determined by the various knob and switch settings on the front
panel, along with the switches and controllers wheels in the left-hand controller section.
Creating Sounds
To create your own sounds from scratch, it’s best to start from a default patch configuration. This will give
you a familiar starting point and guaranty that sound will be produced. To set the Voyager OS to a default
patch, adjust the knobs and switches according to the light blue/grey markings on the panel. This will give
you a basic one-oscillator square wave sound that will act as a blank canvas for your sonic creations.
After you adjust the Voyager panel controls to the default settings, try the controls to the right of the Mixer,
one at a time, starting with FILTER CUTOFF, and notice how they affect the sound. Then try combining
different tones with the Mixer and Oscillators 2 and 3. Finally experiment with the Mod Busses to see
how different types of modulation affect the sound.
When working with the Voyager, keep in mind that many of the controls are interactive, so there is
frequently more than one way to control a single parameter. This may be a source of confusion at first.
For instance, if the SUSTAIN control of the Volume Envelope is all the way down, and the ATTACK and
DECAY knobs are set to zero, there will be no output. Similarly, if you have a sound where the AMOUNT
TO FILTER knob for the Filter Envelope is set to zero, then changing the Filter Envelope ATTACK control
will likely result in no audible change. To use your Voyager to its fullest potential, it is very important to
understand the workings of all the controls and how they interact in order to understand how a sound (or
lack thereof) is produced. Don’t get frustrated; simply work systematically until you know what each control
does and how it works with the rest of the Voyager.
If you are new to subtractive synthesis, be sure to read the synthesis tutorial that appears in Appendix D.
Warranty registration
Moog’s on-line warranty registration system is the best way to activate your warranty. Access the Moog
web site at and click on the “Product Register” tab. If you complete all the requested
information, Moog Music will send you a complimentary gift.
NOTE: The Voyager is recommended for an operating temperature between about 50 and
100 degrees Fahrenheit. It is safe to operate the synthesizer outside of this range (between 0
and 125 degrees F), but the Voyager’s voltage controlled oscilators (VCOs) may not remain in
It is recommended that a warm up period of about 15 minutes be allowed before using the
Voyager. The warm up period may be longer if the Voyager has been stored outside the recommended operating temperture range.
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Voyager OS User’s Manual - The Basics
Overview and Features
The Voyager OS is a monophonic analog performance synthesizer that is a successor to the classic Model D
Minimoog. Its sound sources are three analog, variable waveform oscillators, a noise source, and an external
audio input. Extensive modulation and filtering options give the Voyager OS an expansive sound palette.
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Voyager OS User’s Manual - The Basics
Back Panel:
The Voyager’s back panel offers connections for Power, Control Voltage
(CV) and Gate I/O, and Audio I/O.
There are 14 CV inputs and 2 CV outputs provided on 1⁄4“ jacks. Jacks identified with a red nut indicate a combination CV/Expression Pedal input, while
jacks identified with a blue nut indicate
a combination Gate/footswitch input.
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Voyager OS User’s Manual - The Basics
Signal Flow
To understand the signal flow of the Voyager OS, it’s helpful to consider the three types of signal routings in the system: the audio path, the control voltage path, and the modulation path.
Audio Path
The Voyager’s audio path includes all of the signal sources and signal modifiers that produce an audio
output. These include the oscillators, mixer, filters and amplifiers (VCAs).
The Oscillator section includes controls for selecting the octave and waveforms, adjusting the tuning of
the second and third oscillators, for setting the oscillator sync and linear FM functions, and for setting the
frequency range and keyboard control for Oscillator 3.
The Mixer section is where the oscillators and other sound sources (noise and external input) are
selected and mixed together. The output of the Mixer section is routed to the Filter section through a
Mixer Out/Filter In jack on the Voyager’s rear panel. This jack allows you to interrupt the signal routing
between the Mixer and Filter to insert an external effect, or take the output of the Mixer directly.
The Filter section is responsible for altering the harmonic content of the combined sound sources. The
Voyager’s Filter section contains two filters that work together in two different modes.: Dual LP and
HP/LP. Dual LP mode features two lowpass filters in parallel, while HP/LP (Highpass-Lowpass) mode
features a lowpass and highpass filter in series, creating a Bandpass filter response. In either mode, the
Filter Cutoff control affects the cutoff frequency of both filters, and the Spacing control is used to adjust
the difference between the cutoff frequencies. The outputs of the filters are routed to the Voltage
Controlled Amplifiers (VCAs).
The VCAs shape the volume level of the audio signal using time-varying control signals called Envelopes.
The Envelopes section (part of the control voltage path) contains one Envelope Generator to control
the Filters, and one Envelope Generator to control the VCAs. The Voyager’s audio path is illustrated
The Voyager OS Audio Path
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Voyager OS User’s Manual - The Basics
Control Voltage Path
When a key is pressed, a Gate and Pitch Control Voltage (CV) are produced. The Gate signal is used to
trigger both the Filter and Volume Envelope Generators (EGs). The Pitch CV is used to determine the
pitch of the Oscillators and can be applied to a varying degree to the Filters through the Keyboard Control
Amount knob. The basic control voltage path is illustrated below.
The Voyager OS Control Voltage Path
Modulation Path
Modulation is performed through the Modulation Busses. There are two separate mod busses labeled Mod
Bus 1 and Mod Bus 2, but both busses are identical in function and modulation options. For each Mod Bus,
a Modulation Source, Controller, Destination and Amount are selected. There are six modulation Sources,
six Controllers and six Destinations available. The Modulation Buss routing is illustrated in the figure on the
next page.
One of the modulation sources is a dedicated Low Frequency Oscillator (LFO), which offers triangle and
square waves as well as stepped and smooth Sample and Hold signals.
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Voyager OS User’s Manual - The Basics
The Voyager OS Modulation Buss
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Voyager OS User’s Manual - The Components
The Components
Now let’s take a look at the individual module components that make up the Voyager OS Synthesizer, starting
with the Mixer section. Then we’ll cover the Oscillators, Filters, Envelopes, and Output Sections, the LFO and
Modulation sections, the Keyboard and Left-Hand controllers, and the Back Panel.
A. The Mixer Section
The Mixer combines the main sound sources of the Voyager. It’s a good place to start when creating a new
sound from scratch, or figuring out how a sound is put together. All five of the Voyager’s sound sources can be
switched ON or OFF, and their levels can be individually adjusted.
The five sound sources are:
- External Audio Input
- Oscillator 1
- Oscillator 2
- Oscillator 3
- Noise Source
Each sound source in the Mixer has a dedicated ON/OFF switch and a level control.
The audio output of the Mixer is routed to the Filter through an insert jack on the
Voyager’s back panel. If an insert cable is plugged into this jack, the Mixer output can
be routed through an external effect and returned back into the Voyager OS signal
path. This jack can also be used as direct output of the Mixer if desired (see page 14
for more information).
Mixer Section Controls:
Oscillator 1, 2 & 3:
The OSCILLATOR controls in the Mixer allow each oscillator to be switched ON or OFF, and mixed
in any proportion. When the levels of the oscillators are set high, the output from the Mixer gently
overdrives the Filter section. This was one of the important features in the original Minimoog that gave it
its characteristic ‘fat’ sound.
The NOISE control is used to mix noise with the other sound sources. The Voyager’s Noise source is
a white/pink hybrid. It is useful for making ocean wave sounds, explosions, and wind sounds, or to add a
wind noise component to traditional instrument emulations, or for adding subtle coloration to a sound.
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Voyager OS User’s Manual - The Components
The EXTERNAL control allows an external monophonic audio source to be routed into the Mixer, where
it can be mixed with the Oscillators and Noise source (an “Ext Audio In” jack on the Voyager back panel is
provided for this input). The LED above the EXTERNAL control knob begins to light up as the input signal
overdrives the Mixer input. When the light is faint, a small amount of soft clipping is occurring. When the
LED is bright, the signal is strongly overdriven. Judicious use of overdrive can really fatten up a sound. The
External Audio Input can accept a signal from instrument level to line level.
Mixer Back Panel Connections:
Mix-Out Loop:
The jack on the back labeled “Mix Out/Filter In” is an insert point between the Mixer output and the Filter
input. Using a standard insert cable, an effect such as a moogerfooger® MF-102 Ring Modulator can be
inserted to add effects to the oscillator, noise source, and external audio in prior to the Filter stage. The
Mixer output signal appears at the tip of the insert cable jack as shown below. The return signal is applied
to the ring of the jack. A cable fully plugged into the jack breaks the connection between the Mixer and the
Filter, and unless the Return signal is sent to the ring of the jack, no signal will pass through to the Filter. The
level settings in the Mixer affect the output level, so keep this in mind as you try different devices in this loop.
The Mix-Out loop adds tremendous
flexibility to the powerful sound
creation abilities of the Voyager OS!
PERFORMANCE TIP: Got a few guitar stompboxes laying around? The Mix-Out loop allows
you to easily insert guitar pedal effects into the Voyager’s signal path. What to try? Nearly any
type of sound effect device or sound modifier is fair game (chorus, phaser, flanger, overdrive,
distortion, graphic/parametric EQ, tube preamp, exciter, etc.) and all are worth checking out.
As always, experimentation is encouraged!
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Voyager OS User’s Manual - The Components
B. The Oscillator Section
The Oscillators are the main sound source of the Voyager. The oscillators in the Voyager are all analog
Voltage Controlled Oscillators, or VCOs. They feature a temperature regulation circuit that provides them
with excellent tuning stability. The VCOs can produce a total musical range of 8 1⁄2 octaves! In addition, the
frequency of oscillator 3 can be set to the sub-audio range (<20Hz) for use as a second LFO.
Oscillator 1 performs as a master oscillator to which
Oscillator 2 and 3 are tuned. The timbres of the oscillators
are adjusted by their variable Waveform controls. In addition,
there are switches for Oscillator 2 sync to Oscillator 1;
linear frequency modulation of Oscillator 1 by Oscillator 3;
Oscillator 3 keyboard control ON/OFF; and Oscillator 3 Lo
or Hi frequency range.
The frequencies of the Oscillators are controlled by a number
of sources. The main source is the pitch CV generated
by keyboard. A glide circuit can be switched in between
the Keyboard CV and the oscillators to slow the changes
between notes, producing glissando. The Keyboard CV is
internally mixed with the Octave switch CV, the Frequency
control (Oscillators 2 and 3), the Pitch Bend Wheel, the Fine
Tune control, and the output of the Mod Busses when the
‘Pitch’ destination is selected.
Oscillator Section Controls:
Each Oscillator has a 6-position OCTAVE switch that selects the relative frequency range. To hear how it
works, turn off Oscillators 2 and 3 in the Mixer. Switch Oscillator 1 ON and set its level to 5. Play a note
on the keyboard and rotate the Oscillator 1 octave switch clockwise one click – the note will rise an octave.
You can use this control to change the frequency range that the keyboard controls. The panel markings
from 32’ up to 1’ are octave standards based on organ stops.
Oscillators 2 and 3 have a FREQUENCY control. When the control is in the center position, the oscillators
should be in unison with the frequency of Oscillator 1 (when the octave switches for all three oscillators
are in the same position). The Frequency control can change the pitch of Oscillator 2 or 3 a total of +/- 7
semitones relative to Oscillator 1. This allows more than one frequency to be played when a key is pressed,
or to get a swirly chorus sound when the oscillators are slightly out of tune.
NOTE: The Oscillator FREQUENCY controls have no calibration - sometimes unison tunings
are made with the controls a little left or right of center. Oscillator 1 does not have a Frequency
control because it is designed to serve as a reference oscillator for the other 2 oscillators.
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Voyager OS User’s Manual - The Components
Each oscillator features a continuously variable WAVE (waveform) control. The legend on the front panel
shows the standard waveforms that are available at certain positions on the dial: triangle, sawtooth, square,
and rectangular. The waveform is morphed gradually from one to another as the WAVE control is rotated.
Because the waveform is voltage controlled, this parameter can be modulated; this generates some very
interesting timbral changes. By limiting the modulation between
the square and rectangular waveform, you can get pulse width
modulation (PWM). Although the waveforms can be set from the
front panel individually for each oscillator, modulation through the
Mod Busses affects all three waveforms simultaneously. When using
modulation, it is possible to make the width of the rectangular wave
so skinny that it becomes silent.
1-2 Sync:
The 1-2 SYNC switch is one of four switches located at the bottom of the oscillator panel. In the ON
position, the 1-2 SYNC switch synchronizes Oscillator 2 to Oscillator 1. Oscillator sync is an effect caused
by resetting an oscillator waveform’s start point with another
oscillator as shown here (the effect is more noticeable if the synced
oscillator is a higher frequency than the reset oscillator). The main
frequency heard is that of the reset oscillator. As the frequency
of the synced oscillator is swept, it reinforces the harmonics of the
reset oscillator. Depending on how it is applied, the effect can be
aggressive or warm and vocal. This effect is much more dramatic
when Oscillator 2 is set to a higher octave than Oscillator 1.
3-1 FM:
In the ON position, the 3-1 FM switch turns on linear Frequency Modulation (FM) of Oscillator 1 by
Oscillator 3. When an Oscillator is used as a CV source for another VCO, it is called frequency modulation.
Frequency modulation effects can vary from vibrato or trill effects to clangorous inharmonic sounds to
rich timbres that evoke acoustic sounds. Linear FM is the kind of frequency modulation used in classic FM
3 KB Cont (Oscillator 3 Keyboard Control):
The 3 KB CONT switch disables keyboard control of Oscillator 3 when in the OFF position. By disabling
the keyboard control, you can use Oscillator 3 as a drone or as a modulation source whose frequency
doesn’t change with the key played. In addition to turning off the keyboard control of Oscillator 3, switching
to OFF increases the amount by which the Oscillator FREQUENCY control changes the frequency of
Oscillator 3.
3 Freq (Oscillator 3 Frequency):
The 3 FREQ switch selects the frequency range of Oscillator 3. When the switch is in the LO position,
Oscillator 3 operates as a sub-audio sound source (producing clicks) or as a modulation source (LFO).
When the switch is in the HI position, Oscillator 3 operates with the same available frequency range as
Oscillator 2.
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Voyager OS User’s Manual - The Components
Related Oscillator Controls:
Two other panel controls interact with the Voyager Oscillators: Fine Tune and Glide. These controls are
located in the lower left of the Voyager’s front panel
Fine Tune:
The FINE TUNE control is used to tune the Voyager’s oscillators +/ – 2 semitones
for matching an external reference pitch.
Glide Rate:
Glide enables a glissando effect between notes. The GLIDE RATE control adjusts
the rate of the glissando. The glide rate can vary from a very fast to a very slow
glide. It is switched on or off using the GLIDE switch in the Voyager keyboard lefthand controller section.
Additional CV Connections (Input)
The PITCH jack allows you to connect an external CV or expression pedal to control the Voyager’s pitch.
All three oscillators are effected by this connection. The effective input range is -5 to +5V, where a positive
CV will add to the oscillator dial settings, and a negative CV will subtract from the settings. If an expression
pedal is plugged in, the pitch can only be made to increase (the pedal connection supplies only a positive
The WAVE jack allows you to connect an external CV or expression pedal to control the oscillator waveforms. All three oscillators are effected by this connection. The effective input range is 0 to +5V, resulting in
a full sweep of the waveforms. A voltage applied to this jack will add to WAVE dial panel setting, making it
possible to force the width of the rectangular wave so skinny that it becomes silent.
Additional CV Connections (Output)
Keyboard CV (KB CV):
The KB CV jack outputs the keyboard pitch control voltage, allowing you to control external CV gear. The
KB CV output is 1V/octave.
Keyboard Gate (KB GATE):
The KB GATE jack outputs a gate trigger signal every time a key is pressed. The Gate signal is a +5V trigger
that can be used to trigger external envelope generators, sequencers, or other sources.
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Voyager OS User’s Manual - The Components
C – The Filter Section
Filters are used to adjust the tone color of an audio signal. Filters modify sounds by rejecting some
frequencies while allowing others to pass through. To understand the operation of filters and how they
process sound, there are a few important terms to know.
The first is ‘Cutoff Frequency’. The cutoff frequency is the point at which an audio
signal’s frequencies begin to be rejected. Then there are the different types of filters;
some of the most common and most musically useful filter types are ‘lowpass’,
‘highpass’, and ‘bandpass’. A lowpass filter behaves as its name indicates; it passes all
frequencies below the cutoff frequency and rejects frequencies above the cutoff. A
highpass filter does the opposite. It passes all frequencies above the cutoff point and
rejects the frequencies below the cutoff. A bandpass filter does a bit of both, since it
is created by combining lowpass and highpass filters. In the case of a bandpass filter,
the lowpass section defines the maximum frequency that will pass through, while the
highpass section defines the minimum frequency that will pass through. What’s left
is a band of frequencies that will pass through the filters unaffected, hence the name,
Another key filter term is the ‘Cutoff Slope’. The cutoff slope determines the amount
of attenuation that occurs above the cutoff frequency. The cutoff slope is specified
in decibels per octave (commonly written as ‘dB/oct’). The electrical design of a filter
determines the cutoff slope. You may have heard the term ‘pole’ as it refers to filters. A
pole is simply a design aspect of a filter, and each pole in a filter adds 6dB to the cutoff
slope. This means that a one-pole filter has a cutoff slope of 6db/oct, a 2-pole filter has
a 12dB/oct cutoff slope, etc. The classic Moog filter – the sound that started it all – is a
dB/Oct lowpass filter.
The last filter term to consider is ‘Resonance’. Resonance refers to a peak that appears at the cutoff
frequency. In synthesizers, this resonant peak is usually an adjustable parameter (called ‘ Resonance’ ) that
is part of the filter controls. When the resonant peaks of the lowpass filters pass through the overtones of
the sound being filtered, those overtones are reinforced. This gives the
filter a character that can sound vocal, quacky, or zappy, depending on
how it’s used. When the resonance is turned up past about 8 on the
dial, the filter begins to self-oscillate at the cutoff frequency, producing a
sine wave tone. The Keyboard Control Amount control sets how much
the filters’ cutoff frequencies track the keyboard note that is played. As
you play higher on the keyboard, the cutoff frequency goes higher, too.
In the original Minimoog, the Resonance control was called ‘Emphasis’. Many of
the current Minimoog emulations (both hardware and software) use the term
‘Emphasis’ instead of ‘Resonance’ in the filter section to preserve the authentic
vibe of the original hardware.
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Voyager OS User’s Manual - The Components
The Voyager has two voltage controlled filters (VCF’s) that can be configured either as dual lowpass filters
or as a combination of highpass & lowpass through a front panel switch.
Dual Lowpass Mode:
The Voyager’s Dual Lowpass mode provides two
identical lowpass filters which are routed to the left and
right audio outputs respectively, creating a stereo effect.
The CUTOFF knob controls the frequency cutoff of
both filters. The filters can be set to the same cutoff
frequency, or adjusted to different cutoff frequencies
using the SPACING control. When the two filters are
set at different cutoff frequencies and routed to two
different speakers, what you hear can be a fantastically
swirly and vocal sound – similar to a phaser effect. In
Dual Lowpass mode, the RESONANCE control affects
both filters identically.
Highpass/Lowpass Mode:
In Highpass/Lowpass mode, the Voyager’s filters are
configured as a lowpass and highpass filter in series,
resulting in a bandpass filter. In this configuration, the
output of the filter is routed to both outputs. As with
the Dual Lowpass mode, the CUTOFF control changes
the cutoff frequency of both filters, and the SPACING
control sets the frequency difference between the
Highpass filter and Lowpass filter. The spacing between
the two filters creates a variable passband. In this mode,
the RESONANCE control affects only the Lowpass
filter, thus making for some terrifically interestingly filter
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Voyager OS User’s Manual - The Components
Filter Section Controls:
The CUTOFF knob is the main filter control. This sets the cutoff frequency of both filters in Dual Lowpass
and Highpass/Lowpass mode.
In Dual Lowpass mode, the frequencies to the right of the indicator on the knob are the frequencies that
are filtered out. The frequencies to the left of the indicator are the frequencies that are allowed to pass
through the filter. This is why as you turn the control clockwise the cutoff frequency becomes higher and
the sound becomes brighter. Of course, to hear the effect of a lowpass filter it helps to have a signal rich
in harmonics which provides high frequencies to filter. A good example of a sound rich in harmonics is a
sawtooth waveform.
In Highpass/Lowpass mode, the combination of highpass and lowpass filters forms a bandpass filter. In this
mode, the CUTOFF control changes the center frequency of the passband.
The SPACING control is used to determine the difference between the cutoff frequencies of the two filters
in both Dual Lowpass mode and Highpass/Lowpass mode. The numbers on the legend around the control
knob refer to octaves. When the SPACING control knob is centered, the cutoff frequencies of the two
filters are identical and the filter sounds like a classic Moog Filter. Setting the SPACING control to +1 in
Dual Lowpass mode means that the right filter has a cutoff frequency equal to where the CUTOFF control
knob is set, and the left frequency has a cutoff frequency that is one octave higher than the right filter. This
means when the CUTOFF control is swept, two resonant peaks are heard, giving the filter a unique quality.
In Highpass/Lowpass mode, the SPACING control sets the difference between the cutoff frequencies by
shifting the Highpass filter cutoff frequency up or down. When the SPACING control is fully clockwise, the
cutoff frequencies of the two filters are the same, making for a very narrow bandpass filter.
The RESONANCE control causes feedback in the filter circuit that adds harmonic emphasis at the cutoff
frequency. This control affects the Lowpass filter(s) in either filter mode, but not the Highpass filter. When
the RESONANCE control is all the way down, the lowpass filters act as a tone control, rolling off the high
end (treble) as the CUTOFF control is turned down. As the resonance increases, the filter begins to form
a peak at the cutoff frequency. These peaks reinforce the harmonics of the signal being filtered, creating an
effect that can be described as vocal, nasal, or (at high resonances) zappy. As the RESONANCE control is
turned up the peak increases in strength until the control is set to about 8 or higher, where it begins to selfoscillate, creating sine waves with the same frequency as the cutoff frequency.
Keyboard Control Amount:
The KEYBOARD CONTROL AMOUNT knob allows the filter cutoff to follow the key played on the
Voyager keyboard. A higher key will cause a higher cutoff frequency. This allows a sound to retain its
brightness as it is played higher on the keyboard.
The filter MODE switch selects either the Dual Lowpass configuration (DUAL LP) or the Highpass/Lowpass
configuration (HP/LP).
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Voyager OS User’s Manual - The Components
Additional CV Connections
The FILTER jack allows you to connect an external CV or expression pedal to control the filter cutoff
frequency. Both filters are effected by this connection, regardless of the filter mode setting. The effective
input range is -5 to +5 V, where a positive CV will add to the filter cutoff dial setting, and a negative CV will
subtract from the setting. Note that if an expression pedal is plugged into this jack, the cutoff can only be
made to increase from the cutoff dial setting since the pedal connection supplies only a positive voltage.
D. The Envelopes Section
Musical sounds have a start, middle and an end. For example, a plucked string sound starts with an initial
burst of energy and then slowly fades out until it is silent. In synthesis terms, this progression is called an
envelope – a shape that defines the changes that occur in a sound over time. An envelope can define any
aspect of change in a sound – volume, timbre, or pitch. The circuits that create envelope control signals in
synthesizers are called Envelope Generators (EGs).
When triggered, EG’s produce a time-varying control voltage that has a
specific start, middle and end profile. The four parameters that define
this profile are Attack, Decay, Sustain and Release, sometimes abbreviated as ADSR.
Attack determines the character of the onset of the sound. The EG’s
ATTACK knob controls this parameter by adjusting the time it takes
for the envelope to go from zero to full value (in other words, the
fade-in time). The DECAY control adjusts the second stage in the
envelope’s evolution by determining the time that it takes for the signal
to drop from the full level to the level set by the SUSTAIN control.
The envelope will remain at the Sustain level as long as an envelope
gate signal is present (i.e. a key is held down). When the gate signal is
released, the RELEASE control determines the time it takes for the envelope to transition from the Sustain level to zero (refer to the ADSR
Envelope Signal figure below).
The Voyager has two identical EG circuits; one EG is dedicated to the
filter (to control the cutoff frequency), and one is EG dedicated to
the amplifier (to control the volume). Both EG’s can also be used as
a modulation sources or modulation control through the Modulation
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Voyager OS User’s Manual - The Components
Envelope Section Controls:
The ATTACK control sets the attack time of the corresponding envelope generator, from 1 msec to 10
The DECAY control sets the decay time of the corresponding envelope generator, from 1 msec to 10
The SUSTAIN control sets the corresponding level for the sustained part of the envelope.
The RELEASE control sets the release time of the corresponding envelope (the time for the envelope
to transition from the sustain level to zero), from 1 msec to 10 seconds.
Amount To Filter:
For the Filter Envelope, there is an AMOUNT TO FILTER control that adjusts the amount of the filter
envelope signal that modulates the filter. The AMOUNT TO FILTER control has both positive and
negative values. If it is set to a positive value (say ‘+2’), the envelope will add to the Filter CUTOFF dial
setting. If it is a negative value (say ‘–2’), the envelope will subtract from the Filter CUTOFF dial setting.
Envelope Gate:
Envelopes are triggered by a gate signal. The envelopes will sustain as long as a gate signal is present.
When the gate is off, the Release portion of the envelope is executed as shown below. The switch
labeled KEYB/ ON/EXT selects whether the envelopes are triggered from the keyboard, or from
another gate source. When KEYB (Keyboard) triggering is selected, the envelopes are triggered by
a gate trigger signal that is generated when a note on the keyboard is played. When the switch is set
for ON/EXT (On/External), the envelope gate source defaults to ON if nothing is plugged into the
ENV GATE jack on the Voyager back panel, and the envelopes will sustain at the level determined by
their respective SUSTAIN controls. This is useful for keeping the envelopes sustaining without holding
a key down, when you want to process an external audio signal through the filters with out using the
keyboard, or to create drones.
Envelopes sustain as long as a Gate
Trigger is present. The Release phase
starts when the Gate Trigger stops.
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Voyager OS User’s Manual - The Components
Related Controls
Release Switch:
The release time of the envelopes is set by their respective RELEASE control knob, but this control can also
be switched OFF. On the Voyager OS , there’s a dedicated RELEASE switch located in the left-hand control
panel for this.
NOTE: The Release function is actually a divider for the release time, so if the
RELEASE control knob is set to 10, the release of the envelopes will not be
absolutely abrupt with the RELEASE ON/OFF function switched off.
Additional CV Connections:
Gate (Envelope Gate Input):
The GATE jack allows you to connect a footswitch or input a CV gate signal to remotely trigger both
Envelope Generators. This input triggers the EG’s only when the front panel ENV GATE switch is set to
‘ON/EXT’. If the ENV GATE switch is set to ‘KEYB’, any input on the GATE jack will be ignored.
The RELEASE jack allows you to connect a footswitch or input a CV gate signal. Pressing the footswitch
or applying a gate signal (+5V) enables the Release phase of both Envelope Generators regardless of
the setting of the RELEASE switch.
Rate (Rate Control Input):
The RATE jack is a CV input for external control of the Voyager’s envelope time constants, using either a
CV or expression pedal. The effective input range is -5V to +5V and effects both envelopes. A positive
voltage applied to the RATE jack will decrease the attack, decay and release times from the envelope
panel knob settings, and a negative voltage will increase the
attack, decay and release times from the panel knob settings
as shown.
The envelope AD&R parameters
will expand and contract based on
the voltage at the RATE jack.
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Voyager OS User’s Manual - The Components
E. The Output Section
The Voyager has two audio outputs. There is a Voltage Controlled Amplifier (VCA) for each output, which
allows for stereo functions such as panning or the dual lowpass filtering. The main control for the volume is
the Master Volume control. The Volume Envelope Generator modulates the output VCAs.
Output Section controls:
Master Volume:
The MASTER VOLUME knob is the main volume control. Full-clockwise is
maximum output, full-counterclockwise silences the Voyager. .
Headphone Volume:
This HEADPHONE VOLUME knob controls the volume that appears on
the HEADPHONE OUTPUT jack. Full-clockwise is maximum output, fullcounterclockwise silences the Voyager.
Headphone Output:
The HEADPHONE OUTPUT connection is a 1⁄4” TRS jack that outputs the
Voyager signal to a pair of stereo headphones.
Additional CV Connections:
The VOLUME jack allows you to connect an external CV or expression pedal to control the output
volume. Both VCA’s are effected by this connection. The effective input range is 0 to +5V, where
0V = Volume OFF, and +5V = Full Volume.
NOTE: The Master Volume knob sets the maximum volume of the Voyager OS
output regardless of the signal applied at the VOLUME jack.
The PAN jack allows you to connect an external CV or expression pedal to control panning between
the right and left outputs. The effective input range is -5 to +5V, where -5V = Fully Left and
+5V = Fully Right. If an expression pedal is plugged into the PAN jack, the pedal will reach its full
positive effect over just half of its useful travel, since it gets +5V from the PAN jack. Note also that you will
not be able to pan left with the pedal without additional offset programming because the expression pedal
voltage does not go below 0V.
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Voyager OS User’s Manual - The Components
F – The Modulation Buss Section
Modulation is the heart of making interesting sounds with analog subtractive synthesis. The Voyager’s two
Modulation Busses open up a world of modulation possibilities that were not available on the original
The Modulation Busses allow you to select a variety of modulation
sources, destinations, modulation controllers, and amounts. The
two Mod Busses are labeled MOD BUS 1 and MOD BUS 2, and
are identical in function. The control of each mod buss is selectable
instead of being tied to a particular controller, and six controller
options are available.
Each Mod Bus can select from six modulation sources, six destinations
and six controllers. One of the available controllers is the MOD
1 input on the back panel. This input can accept either a CV or an
expression pedal like the EP-2. When an expression pedal is used, the
result is a foot controller that functions just like the Modulation Wheel
to fade in and fade out the desired modulation. If nothing is plugged
into the MOD 1 input when ‘MOD 1’ is selected as the Controller, the
bus AMOUNT control sets the total modulation amount.
The diagram below shows the configuration of a single Mod Bus, but
the controls and selections for both busses are the same.
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Voyager OS User’s Manual - The Components
Two controls modify the amount of modulation sent to the destination: the selected controller (set with the
CONTROLLER knob) and the AMOUNT control. When the selected controller is a performance control
such as the Mod Wheel or Key Velocity, the modulation can be selectively varied from 0 to 100%. When
the selected controller is an envelope, the modulation varies according to the envelope parameters. In both
cases, the AMOUNT control always sets the maximum amount of modulation.
To try out a simple modulation effect, make the following settings:
On the LFO:
- Set the RATE control to about 6 Hz
- Set the WAVE control to the Triangle wave
On Mod Bus 1:
- Set the SOURCE control to ‘LFO’
- Set the DESTINATION control to ‘PITCH’
- Set the CONTROLLER selector to ‘MOD WHEEL’
- Set the AMOUNT control to 2
These settings allow the Mod Wheel performance control to be used to fade in the modulation, which
should sound something like vibrato. This is a simple use of a Mod Bus. The flexibility of the two Modulation Busses offer a wealth of modulation possibilities which make the Voyager OS an incredible sound
design tool.
Modulation Bus Section Controls:
The SOURCE control selects the source of the modulation. There are six selections available:
- LFO (Low Frequency Oscillator)
- OSC 1 (Oscillator 1)
- OSC 2 (Oscillator 2)
- OSC 3 (Oscillator 3)
- ON/MOD2: If nothing is plugged into the MOD2 jack, this selection is ON
The DESTINATION control selects the destination of the modulation. The modulation destination is chosen in the same manner as the source. The modulation destination selections are:
- PITCH (the pitch of all three oscillators)
- OSC2 (the pitch of Oscillator 2 only)
- OSC3 (the pitch of Oscillator 3 only)
- FILTER (the Cutoff Frequency of the filter)
- WAVE (the waveforms of all 3 oscillators)
- LFO (the Low Frequency Oscillator)
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Voyager OS User’s Manual - The Components
The CONTROLLER dial selects from six modulation controller options. The Controller selections are:
- MOD WHEEL: This allows the modulation source to be controlled from the Modulation
Wheel in the left-hand controller section.
- ON/MOD1: This allows the modulation source to be controlled by a CV or expression pedal
plugged into the back-panel MOD1 jack. If nothing is plugged into the MOD1 jack
when this is selected, the Mod Bus AMOUNT control will set the total amount of
- VELOCITY: This allows the modulation source to be controlled by the keyboard velocity.
- PRESSURE: This allows the modulation source to be controlled by keyboard aftertouch.
- FILT. ENV: This allows the modulation source to be controlled by the Filter Envelope.
- VOL. ENV: This allows the modulation source to be controlled by the Volume Envelope.
The AMOUNT control is used to set the maximum amount of modulation that is sent to the modulation
destination. When the AMOUNT control is set to 0, no modulation will pass. When AMOUNT is set to
10, the maximum amount of modulation is sent to the destination when the selected performance controller is set to maximum (such as the Mod Wheel) or when the controller reaches maximum levels (such as
the envelopes)
Additional CV Control
MOD 1:
The MOD 1 jack accepts an expression pedal or control voltage from 0 to 5 Volts. With nothing plugged
into this jack, the voltage here is 5V (the ‘ON’ state).
MOD 2:
The MOD 2 jack allows you to apply an external modulation source into the MOD busses. The input
accepts an expression pedal or a control voltage of –5 to +5. With nothing plugged into this jack, the voltage
here is 5V (the ‘ON’ state). When the Mod Buss SOURCE control is set to ‘ON/MOD2’, the voltage applied
to this jack becomes the Modulation Source.
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Voyager OS User’s Manual - The Components
G – The LFO
The Voyager OS has a dedicated Low Frequency Oscillator (LFO). The LFO produces triangle and square
waves as well as stepped and smoothed Sample & Hold (S&H) signals over a range of approximately 0.2 to
50 Hz. The LFO signal is available as a modulation source on both Mod Busses.
For the Sample and Hold circuit, the LFO’s square wave is used as the S&H Trigger
input, while the Voyager’s Noise source is used for the S&H Input signal. For each
positive-going cycle of the LFO square wave, the voltage at the input of the S&H
circuit is sampled and held until the next cycle. Since the sample source is Noise
(a random signal), the voltage that appears at the output of the S&H circuit is a
random voltage that changes in time with the LFO.
The Voyager’s CV Interface jacks on the back panel of the Voyager allow additional
flexibility with the Sample and Hold circuit. For example, if a plug is inserted into
the S&H Gate input, it will disconnect the LFO trigger; an external gate signal can
then be used to trigger the S&H circuit. Similarly, a plug inserted into the S&H
Input jack disconnects the Noise source from the S&H input. In this circumstance
when the S&H circuit is triggered, the voltage at the tip of the plug is held at the
output of the S&H circuit. This makes it possible to get interesting modulation
patterns such as the ‘staircase’ modulation shown below.
The Voyager’s Sample and Hold circuit can
create more than just random signals –
interesting stepped modulation patterns
are also possible.
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Voyager OS User’s Manual - The Components
LFO/Sample and Hold Section Controls
The RATE control sets the frequency of the LFO. The RATE control frequency range is approximately 0.2
to 50 Hz.
The WAVE control selects the LFO waveform. There are four waveforms available:
Stepped Sample & Hold
Smooth Sample & Hold
Additional CV Connections:
LFO Rate:
The LFO RATE jack accepts an expression pedal or a control voltage from -5 to +5V. A positive voltage
applied here adds to the position of the LFO RATE control, while a negative voltage will subtract from the
position of the LFO RATE control.
PERFORMANCE TIP: By applying an external voltage to the LFO RATE jack you can
control the LFO frequency well beyond the specified range. Rates lower than one cycle
per minute are possible, as are frequencies that go well into the audio range.
LFO Sync:
The LFO SYNC jack accepts a footswitch or a +5V Gate input. Closing the footswitch or applying a gate
signal here will retrigger the LFO waveform.
S&H In (Sample and Hold Input):
The S&H IN jack accepts an expression pedal or a control voltage from -5 to +5V. The voltage on this jack
is the signal source for the Sample and Hold circuit input.
S&H Gate (Sample and Hold Gate):
The S&H GATE jack accepts a +5V Gate input. Applying a gate signal here will trigger the Sample and Hold
NOTE: The S&H GATE jack will only work with a +5V Gate input, not a footswitch.
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Voyager OS User’s Manual - The Components
H – Keyboard and Left-Hand Controllers
The Voyager OS has a 44-note keyboard (31⁄2 octaves,
F to C), just like the original Minimoog. The Voyager’s keyboard produces velocity and aftertouch (pressure) voltages
monophonically. These voltages can be used as modulation
control signals through the Modulation Busses, or as external
control signals when the Voyager is connected to the optional
VX-351 CV Expander.
To the left of the keyboard is the Left Hand Controller Panel,
which contains the Pitch Bend and Mod Wheel performance
controls, and the Glide and Release switches.
Keyboard Modes
The Voyager OS keyboard priority is LAST NOTE, and the trigger mode is LEGATO. ‘Last Note’ means that
each new note on the keyboard generates a new pitch CV. ‘Legato’ means that as long as any combination of notes on the keyboard is held down, the keyboard Gate signal is high (in other words, Single Trigger
mode). The Voyager OS can also be configured for Multi Trigger mode. ‘Multi Trigger’ means that each new
note played on the keyboard re-triggers the Gate. To place the Voyager OS in Multi Trigger mode, simply
hold down the top two keys of the keyboard as the unit is powered up. The Voyager will revert to Single
Trigger mode the next time the unit is powered up unless the top two keys of the keyboard are held down.
Performance Controls
Pitch Bend Wheel:
This spring-loaded performance control affects the pitch of all three oscillators. The pitch bend amount is
fixed at +/-5 semitones.
Note: The Pitch Bend amount is set by an internal jumper. Although most players will be comfortable
with the factory default setting (+/-5 semitones), wider or narrower ranges can be set by reconfiguring
an internal jumper. For details on this procedure, visit the Voyager Old School section on the Moog
Music web site (
Modulation Wheel:
This performance control adjusts the amount of modulation that is sent to the modulation destination when
the Mod Buss CONTROLLER switch is set to ‘MOD WHEEL’.
The GLIDE switch turns the Glide function ON and OFF. The glide rate is controlled by the GLIDE RATE
panel control.
The RELEASE switch is used to shorten the release time of both the Filter and Volume envelopes. You will
notice that with very long release times, the release time will be shortened when the RELEASE switch is
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Voyager OS User’s Manual - The Components
PERFORMANCE TIP: The expressive use of the Pitch and Modulation Wheels is the key to
breathing musical life into your performances. For example, the Pitch Wheel will allow you to
perform pitch bends like a guitarist, or create on-the-fly half and whole step modulations. The
Mod Wheel can be programmed to introduce standard modulation effects like vibrato, tremolo
or filter sweeps, or it can control something less expected, like the LFO rate. Although the actual
performance technique with these controls is beyond the scope of this manual, we recommend
listening to recordings of synthesizer players, guitarists and other soloists to learn the various ways
these controls can be used effectively.
I – The Back Panel
The back panel provides for all of the Voyager’s connectivity, including power, audio and CV expansion connections.
Power Connector:
This is a standard AC power inlet. Use only a power cord designed to mate with this receptacle. The
Voyager power supply is designed to work with power inputs of 100-240 VAC; 50-60 Hz.
IMPORTANT SAFETY NOTE – Do not alter the power connector in any way. Doing so can
result in the risk of shock, injury or death. Be familiar with the safety instructions printed at the
beginning of this manual. If the connector is damaged, refer servicing to qualified personnel only.
Left/Mono and Right Outputs:
The LEFT/MONO and RIGHT outputs on the Voyager OS are unbalanced 1⁄4” TS jacks for use with
standard TS instrument cables.
When just the LEFT/MONO output is connected, both channels are summed to this output. A stereo
signal is created when both the LEFT/MONO and RIGHT outputs are used. When the Voyager Filter is set
to ‘Dual Lowpass Mode’, the RIGHT output can be used to get a monophonic sound that is unaffected by
the Filter’s SPACING control.
External Audio In:
This is an unbalanced 1⁄4” TS input that accepts any instrument or line level signal and routes the signal to
the Mixer. A dedicated EXTERNAL input control on the Mixer adjusts the signal level.
Mixer Out/Filter In:
This is a 1⁄4” TRS jack that is used for inserting a processing device between the Voyager’s Mixer and Filters.
The tip is the send and the ring is the return (see the illustration on page 14).
CV/Expression Inputs:
The CV/Expression Inputs are 1⁄4” TS jacks color coded with a red nut. These jacks accept an input from
an expression pedal such as the Moog EP-2, or a CV from -5V to +5V. Note that some inputs, such as the
MOD 1 input, operate only from 0V to +5V; a negative CV applied here will have no effect.
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Voyager OS User’s Manual - The Components
Gate/Footswitch Inputs:
The Gate/Footswitch Inputs are 1⁄4” TS jacks color coded with a blue nut. These jacks accept an input from
a footswitch (a momentary, normally-closed footswitch like the Moog FS-1) or a +5 Volt Gate Signal.
NOTE: The Sample and Hold input jack ONLY accepts a Gate input.
CV Output:
The Keyboard Pitch CV (labeled ‘KB CV’) is available at this output. This CV is scaled to 1V/octave. The
actual voltage corresponds to the last note played on the keyboard.
Gate Output:
The Keyboard Gate (labeled ‘KB GATE’) is available at this output. This signal is a +5V trigger signal that is
generated with each key press.
Accessory Port:
The Voyager OS has a DB-25 connector which connects to the optional VX-351 Voyager CV Expander.
This device outputs all the CV and Gate signals that are generated by the Voyager on 1⁄4” jacks. For more
on the VX-351, see Appendix B.
PERFORMANCE TIP: You can use the Voyager OS to process any audio signal simply
by plugging into the EXTERNAL AUDIO IN jack. To hear the external audio signal without
having to hold down a key on the keyboard, set the ENV. GATE switch to ‘ON/EXT’. This
will trigger the envelopes. Make sure that the Volume Envelope SUSTAIN control is set to
maximum. The Volume Envelope will remain at its Sustain level until the ENV. GATE switch
is changed to ‘KEYB’.
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Appendix A - Specifications
Monophonic analog performance
Sound Generation:
3 Oscillators with continuously variable waveform control, 1 Noise source, 5-input Mixer,
2 Filters, 2 Envelope Generators, 1 LFO,
2 Programmable Modulation Busses, Glide
and Fine Tune controls
44 keys (F-C)
Transmits monophonic velocity and aftertouch control voltages
Performance Controls:
Pitch Wheel: +/-5 semitones
(range is internally adjustable)
Modulation Wheel: 0 to 100%
Glide and Release Switches: On/Off
Master Volume Control: 0 to 100%
Stereo Audio Output: Two 1⁄4” jacks on
back panel
Headphone Output: One 1⁄4” TRS jack on
front panel. Dedicated Headphone
Volume control.
30.5” W x 18” D x 3” H (panel flat)
30.5”W x 18”D x 12” H (w/panel fully upright)
40lbs (18.2 kg)
Specifications subject to change without notice
Back Panel:
AC Power Inlet (universal power supply,
100-250 VAC, 50-60 Hz)
Power ON/OFF switch
Stereo Audio Output jacks
External Audio In jack
Mixer Out/Filter In jack
CV/Gate jacks (14 inputs and 2 outputs
that allow external control of
various CV and Gate functions)
Accessory Output Port (DB25 connector)
for optional VX-351 CV Expander
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Voyager OS User’s Manual - Appendices
Appendix B - VX-351 CV Expander
Flash back to the late 60’s: Back in the day, a synthesizer was a behemoth of panels and patch cords. They
were known as modular synthesizers, because each function of the synthesizer was contained in a single
module. A synthesizer was a collection of modules, and the instrument produced no sound until the proper
connections were made between modules using patch cables. This approach afforded the synthesist serious
creative flexibility, and the results of creative “what if ?” thinking often yielded amazing results. The approach
was not without its drawbacks, however, which include:
Space – a modular synth can take up a lot of space.
Time – creating sounds from scratch takes a lot of practice, patience, and time.
Repeatability – documenting a sound is a tedious, labor-intensive process, and not
always accurate
Cost - a good modular synth takes serious money to assemble.
Enter the Minimoog; a portable synthesizer where the most musically useful connections are already in place
and permanently wired. Sounds are created quickly and efficiently using the various knobs and switches
of the well laid out front panel (no patch cords needed!). Also, sounds are easy to document using patch
templates, and, due to its smaller size and weight, the synth can actually be carried to gigs without having to
rely on a road crew. Finally, a serious synthesizer made for the working musician.
Flash forward to today: The Minimoog Voyager Old School is based on the concept of the Minimoog. It is
a portable analog synthesizer with all the basic connections for making great electronic sounds. From its
front panel, the Voyager OS offers even more functions than the original Minimoog, and provides expansion
capabilities through back panel connections that work just like the connections found on a modular
synth. In fact, the Voyager OS can become the foundation of modular system. However, in order to take
full advantage of this capability, you need a way to access all of the Voyager’s control voltage signals, both
incoming and outgoing.
Enter the VX-351...
The VX-351 Voyager CV Expander is an add-on product that expands
your Voyager OS into a semi-modular synth. The VX-351 contains
all of the Voyagers CV and Gate outputs on 1⁄4” jacks (19 CV outputs
and 2 Gate outputs). In addition, there are two active attenuators
for reducing or inverting the strength of a CV signal, and two 4-way
Multiples for sending a single CV signal to multiple control destinations.
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Voyager OS User’s Manual - Appendices
Connecting the VX351:
Make all connections as described below with the Voyager powered OFF
To connect the VX-351, locate the male end (the end with recessed pins) of the DB-25 cable - this
is the end that plugs into the connector on the Voyager’s back panel labeled “ACCESSORY PORT”
Align the cable properly and make the connection. Use the thumbscrews to lock the connection.
Be careful not to force or cross thread the thumbscrews in the accessory port’s female threads.
Following this, connect the other end of the cable to the connector on the VX-351 labeled “FROM
NOTE: The Voyager OS does not require the VX-351 output adapter to be installed
Now let’s start with a basic sound and see how the VX-351 can work with the Voyager.
- Power up the Voyager OS keyboard
- Set the panel controls to the default configuration.
- Using a 1⁄4“ patch cord, plug one end into the VX-351’s LFO triangle output. Plug the other end
into the Voyager keyboard Filter Control Input.
- Play a note on the Voyager and you will hear the LFO modulating the Filter’s Cutoff. Adjusting the
Voyager’s LFO RATE control will change the rate that the Filter Cutoff moves up and down. This
demonstrates a basic patch with the VX-351.
- Now disconnect the cable from the Voyager’s Filter Control and connect it to the IN of one of
the VX-351 Attenuators. Set the Attenuator amount to zero. Using another 1⁄4” cable, make a
connection from the VX-351 Attenuator OUT to the Filter Control Input.
- Play a note and gradually increase the Attenuator amount. You will notice that the amount of
modulation will increase. An Attenuator is used to set the amount of a CV Source that passes to
the Destination.
This is a very basic use for the VX-351, but it demonstrates the fundamental concept of how to use it:
a source always goes to a destination. Using this fundamental concept, you can patch together additional
modulations and get as complex as you like.
PERFORMANCE TIP: As you make CV and Gate connections, think of the output jacks as
your Sources (like the LFO triangle wave in the above example), and the input jacks as your
Destinations (like the Filter Control Input in the above example).
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Voyager OS User’s Manual - Appendices
VX-351 CV Output Expander - Description
The following is a description of the outputs and functions contained in the VX-351 CV Output Expander.
This group of four outputs is not used with the Voyager OS.
This group of outputs is generated from the Voyager’s Keyboard. There are three control voltages (Pitch,
Velocity and Pressure) and one gate signal.
PITCH: This is the CV determined by the note that is played on the Keyboard. It is the same voltage
used for determining the pitch of the Voyager’s Voltage Controlled Oscillators.
This is the CV determined by the velocity used to press a key.
PRESS: This is the CV determined by how much pressure is exerted on a key after it is pressed.
GATE: This is the gate signal generated when a key is pressed.
This group of outputs is generated from the Voyager keyboard’s Left Hand Controller Wheels.
PITCH: This is the CV generated from the Pitch Wheel.
MOD: This is the CV generated from the Mod Wheel.
This group of outputs is generated from the MOD1 and MOD2 jacks on the rear panel of the Voyager.
MOD1: This is the CV generated from the MOD1 input. The MOD1 Input is a CV input on the Voyager
that determines how much of the PEDAL/ON Mod Bus Source goes to the PEDAL/ON Mod
Bus Destination. With nothing plugged into the MOD1 jack, the voltage that’s present at the
MOD1 jack is +5V. When a CV is plugged in to the MOD1 input, that voltage replaces the +5
Volt signal at the MOD1Input. The Voltage that appears at the MOD1 Input is duplicated at the
MOD1 output.
MOD2: This is the CV generated from the MOD2 input. The MOD2 Input is a CV input on the
Voyager that is an external modulation source for the Mod Busses. With nothing plugged into
the MOD2 jack, the voltage that’s present at the MOD2 jack is +5V. When a CV is plugged
in to the MOD2 input, that voltage replaces the +5 Volt signal at the MOD2 Input. The Voltage
that appears at the MOD2 Input is duplicated at the MOD2 output.
This group of outputs is generated from the Voyager’s LFO. There are two CV waveforms available here
(triangle and square) and both can be used at the same time
TRIANGLE: This is the triangle wave output of the LFO.
SQUARE: This is the square wave output of the LFO.
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Voyager OS User’s Manual - Appendices
This group of outputs is generated by the Mod Buss signals. They are the Modulation source after being
shaped by the SHAPING signal at the level determined by the AMOUNT control and the MOD WHEEL or
signal at the MOD1 Input jack
WHEEL: This is the output of the Mod Wheel Mod Buss. It is the Mod Wheel SOURCE shaped by the
SHAPING signal. The level is determined by the AMOUNT control and the MOD WHEEL.
PEDAL: This is the output of the Pedal/On Mod Buss. It is the Pedal/On SOURCE shaped by the
SHAPING signal. The level is determined by the AMOUNT control and the signal at the
MOD1 Input jack.
This group of outputs is the output of the Envelope Generators.
FILTER: This is the CV output of the Filter Envelope Generator.
VOLUME: This is the CV output of the Volume Envelope Generator.
This group of outputs is generated by the Sample and Hold Circuit.
STEP: This is the output of the Sample and Hold Circuit.
SMOOTH: This is the smoothed output of the Sample and Hold Circuit.
The VX-351 contains two attenuators. An attenuator is used to reduce the amount of a CV signal. The
attenuators have an input jack, an output jack, and a knob. The knob sets the amount of the signal present
at the input jack that passes to the output jack. When the knob is set to fully clockwise, the full input signal
passes to the output. When the knob is fully counter-clockwise, no signal passes to the output
The VX-351 contains two 4-way Multiples, or ‘Mults’. A Mult is used to distribute a single source to multiple
destinations. An example is connecting the Voyager’s LFO to the Volume, Filter and Pan Control Inputs. In
this case, all three of those parameters will be controlled simultaneously by the LFO.
NOTE: A Mult is NOT a mixer. Never apply more than one CV source to a mult! Combining
two or more CVs in a Mult can cause them to add together in a way that can be damaging to
some control inputs! If you wish to combine several CV’s, you must use a CV mixer (like the
CP-251 Control Processor’s Mixer) to safely mix these signals.
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The table below shows the effective ranges of the VX-351 Outputs.
(Note 1)
PITCH (Note 2)
-0.916V to 2.667V Nominal
-5 to + 5V
-5 to + 5V
+5V ON, 0V OFF
-5 to +5V
-5 to +5V
MOD1 (Note 3)
-5 to +5V
MOD2 (Note 3)
-5 to +5V
+/- 2.5V
WHEEL (Note 4)
-4 to +4V Nominal
PEDAL (Note 5)
-4 to +4V Nominal
0 - 5V
0 - 5V
-2 to +2V Nominal
-2 to +2V Nominal
+/- 1V Nominal
VX-351 CV Expander Outputs
Note 1: The Touch Surface jacks are non-functional when the VX-351 is used with the Voyager OS.
Note 2: The range shown is the Keyboard Pitch voltage range over the Voyager’s 31⁄2 octave keyboard (F-C). Keyboard Pitch is scaled for 1 V/octave.
Note 3: The MOD1 and MOD2 outputs default to +5V if nothing is connected to the MOD1 and
MOD2 inputs.
Note 4: The jack labeled “WHEEL” outputs the signal from the Voyager OS Mod Bus 1.
Note 5: The jack labeled “PEDAL” outputs the signal from the Voyager OS Mod Bus 2.
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Documenting your work
A list of the Expander connections (like the one shown below) is a convenient way to document CV
routings with the Voyager OS.
KBD Pitch
KBD Velocity
KBD Pressure
KBD Gate
Pitch Wheel
Mod Wheel
LFO Triangle
LFO Square
Mod Wheel Mod Bus
Pedal/On Mod Bus
Filter Env
Vol Env
S&H Step
S&H Smooth
Atten 1/Amount
Atten 2/Amount
Mult A1
Mult A2
Mult A3
Mult A4
Mult B1
Mult B2
Mult B3
Mult B4
1. When connected to the Voyager OS, the four Touch Surface (TS) output jacks
on the VX-351 are not used. These jacks are omitted on the above list.
2. The Mod Wheel Mod Bus jack is the output of the Voyager OS Mod Bus 1
3. The Pedal/ON Bus jack is the output of the Voyager OS Mod Bus 2
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The following are some simple ways to use the VX-351 with the Voyager OS. Gather up some 1⁄4” patch
cords and try these suggestions:
1. Use the Mod Wheel to control Volume
This will configure the Mod Wheel as a volume controller. Perform the following steps:
- Set the panel controls to the default configuration.
- Set the Mod Bus 1 controls as follows:
- Using a patch cord, make a connection between the VX-351 ‘BUSSES WHEEL’ jack and the
Voyager’s VOLUME jack.
- Play a note and move the Mod Wheel. You’ll hear the sound fade in and out as you move the
Mod Wheel back and forth.
- Now adjust the Filter CUTOFF to 60 (about 9 o’clock) and turn the GLIDE and RELEASE
switches ON. Add a slight bit of LFO Pitch modulation from Mod Bus 2, and you have a
theremin-like patch where the volume and timbre is completely controlled by your left hand
while you play the notes with your right hand.
2. Use the LFO to auto-trigger the Voyager’s Envelopes
This is an alternative to triggering a sound from the Voyager by pressing a key. In this example, the last key
you press will determine the pitch, but the LFO will continuously trigger the start of the envelopes.
- Using a patch cord, make a connection between the VX-351 LFO Square Wave jack and the
Voyager’s Envelope Gate (ENV GATE) Input.
- Switch the front panel ENVELOPE GATE switch to ‘ON/EXTERNAL’. You should immediately
hear a note repeating at the LFO rate.
- For a bit of sonic exploration with this setup, try adjusting the LFO RATE control while you tweak
the FILTER CUTOFF, RESONANCE and Envelope controls.
3. Use the Pitch Wheel to control the waveshape
Here’s a way to make your Pitch Bends stand out:
- Set the panel controls to the default configuration.
- Using a patch cord, make a connection between the VX-351 ‘WHEELS PITCH’ jack and the input of an
- With a second patch cord, make a connection between the Attenuator output jack and the Voyager’s
WAVE jack.
- Set the Attenuator to ‘5’ (12 o’clock)
- Play a few notes as you adjust the Pitch Wheel. In addition to affecting the pitch, it will now also
introduce a timbre change as the waveform is modulated. This is a handy way to add emphasis to your
Pitch Bends. This basic technique also works well when the Pitch Wheel output is routed to affect the
Filter Cutoff.
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Appendix C - Using the CP-251 with the Voyager
The Moogerfooger® CP-251 Control Processor makes an ideal
companion to the Voyager OS. The CP-251 provides an LFO with
two waveforms (Triangle/Square), a Sample & Hold circuit with two
outputs (stepped/smooth), a Lag Processor, a Noise source, a Mixer
and two active Attenuators. The combination of Voyager, VX-351and
CP-251 is very much like having a small Modular synthesizer. The
nice thing is that the most basic connections are already made in the
Voyager, so the CP-251 and VX-351 add an extra level of modulation
signal flexibility.
Here are some possible configurations for using the CP-251 with the Voyager. Grab some 1⁄4” patch cords
and try these ideas!
1. Simple configurations using the LFO
The LFO in the CP-251 can be used for common modulations such as vibrato, tremolo, auto-pan and
modulated filter effects, freeing up the Voyager’s LFO for other uses.
To try any of the examples shown below, begin by connecting the CP-251’s LFO Triangle output to an Attenuator Input, then follow the example to complete the modulation routing.
To create Vibrato:
Using a patch cord, make a connection from the CP-251 Attenuator Output to the Voyager’s PITCH
jack. On the CP-251, set the LFO RATE control to 6 Hz (about 1 o’clock), and adjust the ATTENUATOR control to about ‘0.5’ on the dial (a very low amount). This configuration will produce a
constant mild vibrato. Setting the CP-251’s LFO RATE control considerably higher will result in wild
FM textures.
To create Tremolo:
Using a patch cord, make a connection from the CP-251 Attenuator Output to the Voyager’s
VOLUME jack. On the CP-251, set the LFO RATE control to 6 Hz (about 1 o’clock), and adjust the
ATTENUATOR control to ‘10’ on the dial. This will produce a constant tremolo effect. Adjust the
LFO Rate to taste. For a sharp, volume-chopping effect, use the CP-251’s LFO Square wave output
in place of the LFO Triangle out.
To produce Auto-Panning:
Using a patch cord, make a connection from the CP-251 Attenuator Output to the Voyager’s PAN
jack. On the CP-251, set the LFO RATE control to 6 Hz (about 1 o’clock), and adjust the ATTENUATOR control to ‘10’ on the dial. This will produce a constant panning effect. Adjust the LFO
Rate to taste.
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To produce a modulated filter effect:
Using a patch cord, make a connection from the CP-251 Attenuator Output jack to the Voyager’s
FILTER jack. On the CP-251, set the LFO RATE control to 6 Hz (about 1 o’clock), and adjust the
ATTENUATOR to about ‘2’ on the dial. This will produce a cyclical tonal variation as the filter cutoff
frequency is modulated. Setting the CP-251’s LFO RATE control considerably higher will result in
wild timbral textures, while a very low setting will create a slowly evolving filter sweep.
2. Inverting the keyboard CV to the Filters
This is a handy little trick that can be used to lower the filter cutoff as you play higher on the keyboard. This
effect mimics certain acoustic instruments like a cello, whose tone gets duller as higher notes are played.
- Set the panel controls to the default configuration.
- Turn the Voyager Filter KB. CONT. AMOUNT control to ‘0’
- Using a patch cord, connect the VX-351 KBD PITCH output to the CP-251 Attenuator Input.
- With a second patch cord, connect the Attenuator output to the Voyager’s FILTER jack.
- Set the CP-251’s ATTENUATOR control level to -5.
Play a scale up the keyboard, from low to high, and you’ll notice that the sound gets much duller. Adjust the
FILTER CUTOFF and ATTENUATOR controls to taste.
3. Creating Sample and Hold staircase patterns
A Sample and Hold circuit can be used for more than generating random voltages. One type of modulation
pattern that can be achieved is called ‘Staircase’ modulation. It is achieved by feeding a slow triangle wave
into the Sample and Hold circuit and sampling that input at a high rate, effectively chopping the triangle
wave into discreet voltage levels that resembles a staircase. We’ll use two LFO’s for this; a slow one for the
input and a fast one for the trigger.
- Set the panel controls to the default configuration.
- Set the Voyager’s LFO rate to about .4 Hz.
- Using a patch cable, make a connection from the VX-351’s LFO triangle output jack to the
Voyager’s Sample and Hold Input jack (S&H IN).
- Set the CP-251’s LFO RATE control to about 6 Hz (about 1 o’ clock on the dial).
- Using another patch cable, make a connection from the CP-251’s LFO square wave output jack to
the Voyager’s Sample and Hold Gate Input jack (S&H GATE).
- Set the Voyager’s LFO WAVE control to the S&H position.
- Set the Mod Bus 1 controls as follows:
Play a note and move the Mod Wheel forward. You should hear the pitch modulated by an ‘up & down’
staircase waveform.
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PERFORMANCE TIP: There may be times when you want a wider control range than a
single CV provides. It’s possible to increase the control range of a CV using a Mult and the
Mixer in the CP-251. Begin by connecting the CV to a Mult, and then make connections
from the Mult to the Mixer 1 & Mixer 2 inputs. Set the Mixer 1 & 2, and Master levels to
maximum, then route the output to your desired input. (Note: Although the Mixer is effectively doubling the CV signal in this configuration, the Mixer output cannot exceed about
Connecting other CV compatible equipment
We’ve covered some basic uses of the Voyager and the VX-351 and CP-251. Other CV compatible
equipment like our Moogerfooger
Moogerfooger® analog effects can be incorporated to further expand the sonic palette.
Here are some things you could try with a Voyager, a VX-351and our Moogerfoogers:
- Use the Voyager’s Filter Envelope to control the Sweep of a MF-103 12-Stage Phaser.
- Use the Voyager’s Mod Wheel to control the Rate of the MF-103 12-Stage Phaser.
- Use the Voyager’s Mod Wheel to control the Mix on the MF-102 Ring Modulator.
- Use the Voyager’s Noise Output to add roughness to the MF-101’s Filter Cutoff.
- Use the Voyager’s Keyboard Pitch Output to control the VCO in the MF-107 FreqBox.
With all of the control options provided, the possibilities for sound creation are nearly limitless!
We’ve just scratched the Surface
The examples provided here are just a few of the synthesis possibilities afforded by the Voyager OS and our
line of CV Expanders. Other CV compatible equipment can be connected as well; just keep in mind that
you should always connect a source to a destination, and that you shouldn’t combine multiple source CVs
without a mixer. We encourage you to experiment, as there are many possibilities for exploring synthesis
– whether you are trying to duplicate a sound or effect you heard, or if you are trying to make a sound that
nobody’s heard before. Remember - experimentation is part of the fun!
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Appendix D - SynthesisTutorial
For those who are new to the world of electronic music, let’s take a few moments to go through the basics
of sound and synthesis.
Sound is simply the audible change in air pressure. When we perceive
sound, our ears are responding to variations in air pressure that happen to occur in our range of hearing. The rate of these variations is
called the Frequency, which is measured in cycles per second, or Hertz
(Hz). Generally, our ears can hear frequencies from about 20 Hz (on
the low end) to about 20,000 Hz (on the high end). The frequency of
a sound corresponds to its pitch. A low frequency corresponds to a
low-pitched sound (such as a bass) and a high frequency sound corresponds to a high-pitched sound (such as a piccolo).
A second perception of sound is its volume or loudness. Loud sounds
create big fluctuations in air pressure, while soft sounds create small
fluctuations. The measurement of these fluctuations is called the
Amplitude, which is measured in Decibels (dB).
A third perception of sound is its tone color, also known as its timbre. There is no standard of measurement
for timbre, so instead we use familiar terms to describe the tone color of a sound – bright or dull, buzzy or
mellow, tinny or full. The tone color is a function of the harmonic content of the sound. Sounds that are
bright and buzzy have a lot of harmonics, while sounds that are muted and dull have few harmonics.
Harmonics are mathematically related overtones of the base pitch. To explain what that means, let’s consider an example: if the base pitch is 100 Hz, harmonics will occur at 200 Hz (2 x 100), 300 Hz (3 x 100), 400
Hz (4 x 100), etc. The levels of the harmonics are always much lower than the level of the base pitch, and
they decrease as the frequency goes up, so a 200hz harmonic will be louder than a 300Hz harmonic, which
will be louder than a 400Hz harmonic, and so on. Note that there are some sounds that contain overtones
that are not mathematically related to the base pitch. These include the ‘metallic’ sounds created by percussion instruments like cymbals, gongs and chimes, and noise sounds like wind or white noise. The overtones
of these sounds are called ‘inharmonic’, as they don’t fit neatly into a mathematical relationship with the base
Using the electrical circuits in synthesizers, we can manipulate the three parts of sound (pitch, volume and
timbre) to create new sounds and simulate existing ones. This process is called Synthesis. There are a
number of ways to synthesize sound electronically (including frequency modulation, granular, phase
distortion and additive to name but a few), but the method used most often is called Subtractive Synthesis.
In Subtractive Synthesis, you start with signals rich in tone color, and then eliminate (i.e. subtract) frequencies
to achieve the desired sound.
A synthesizer design based on subtractive synthesis typically consists of three main components and three
auxiliary components. The main components are the Oscillator, Filter and Amplifier, and the auxiliary
components are the Keyboard controller, Envelope Generator, and Low Frequency Oscillator.
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The Subtractive Synthesis Model
The Oscillator is the starting point of Subtractive Synthesis, for it is here that the initial sound is created. The
oscillator creates electrical vibrations which function in a manner similar to the strings of a guitar; they create the
signal source that the rest of the system will use to modify and shape the sound. The key oscillator parameters
are pitch and waveform.
The pitch of the oscillator is primarily determined by the keyboard, which creates specific pitches based on an
equal-tempered scale (more about the keyboard later).
The waveform determines the harmonic richness of the audio signal. There are four basic waveforms common
to most synthesizers: sawtooth, square, triangle and sine.
The sawtooth wave is the richest sounding of the four waves. It contains all
of the harmonics, and has a bright, buzzy sound. Sawtooth waves are ideal
for brass and string sounds, bass sounds and rich accompaniments.
The square wave possesses a hollow sound compared to the sawtooth,
owing to the fact that it contains only odd harmonics. This hollow
characteristic is ideal for distinctive lead and sustained (pad) sounds.
An interesting aspect of the square wave is that the waveshape can be
changed to make the top and bottom parts asymmetrical, creating a pulse
wave. By changing the shape of the wave, new harmonics are introduced.
Pulse waves are ideal for creating clavinet-like sounds, but are also useful
for creating lush pads. Many synthesizers allow you to dynamically control
the shape, or ‘width’ of the pulse wave using modulation sources such as a
low frequency oscillator (LFO). This type of waveform control is known as
‘pulse width modulation’, or PWM.
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Like the square wave, the triangle wave only contains odd harmonics,
but the levels of the harmonics in a triangle wave are much less. The
triangle wave has a soft, slightly buzzy sound that is suitable for highpitched leads (like a flute) or adding a beefy sub-bass to bass sounds.
The sine wave is the purest waveform of them all. It has no harmonics,
so it produces a very pure tone. Because of this, sine waves generally
aren’t used as primary audio signals, but are often used to reinforce or
enhance other waves. They are also used as modulation sources.
Synthesizers often have more than one oscillator, and each oscillator usually has its own dedicated frequency,
waveform and level (volume) parameters. Several oscillators make possible rich and complex sound source
configurations. Some synthesizers also permit external audio signals to serve as sound sources, allowing you
to combine them with the oscillators, or process the external audio by itself using the synthesizer components.
The combined sound sources are routed to the Filter, a circuit that removes or reduces frequencies (and
in some cases, emphasizes them). Although there are several filter types designed to remove high, low and
middle frequencies, most synths offer at least one type, and most often it’s a Lowpass filter.
A Lowpass filter gets its name because it allows low frequencies to pass
through while removing or reducing the high frequencies. The point
at which the filter works to remove high frequency signals is called the
Cutoff. Above the cutoff, frequencies are gradually reduced according
to the filter’s ‘slope’, which is a measure of how well the filter works.
The slope of a filter is expressed in decibels per octave (dB/Oct). The
Voyager filter is rated at 24 dB/Oct, which creates a dramatic reduction
in unwanted frequencies. This is a highly desirable quality for subtractive
Another important filter parameter is the filter resonance. Resonance amplifies the frequencies at the
cutoff frequency, emphasizing any signal frequencies that appear there. It’s possible to adjust the resonance
control to the point where the filter actually oscillates. When this occurs, the oscillation frequency is the
same as the cutoff frequency.
The Filtered signal is routed to the Amplifier, which controls the gain (volume) of the signal. The Amplifier controls the dynamics of a sound, turning it on and off as you play. The Amplifier is usually paired with
an Envelope Generator (described below). The gain of the amplifier follows the contours of the Envelope
Generator signal, shaping the sound from start to finish.
The Oscillator, Filter and Amplifier are voltage controlled, meaning that they respond to changes in voltages.
For the Oscillator, it means the higher the voltage, the higher the pitch. For the Filter, it means the higher the
voltage, the higher the cutoff frequency. For the Amplifier, this means the higher the voltage, the greater the
volume. Since each of the three main components respond to a voltage, the entire synthesis system thus
has a common control element. This provides great flexibility for sound programming, and allows auxiliary
components, like Envelope Generators and Low Frequency Oscillators (which generate control voltages) to
further vary the sound.
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Returning to our Subtractive Synthesis model, the first of the auxiliary components is the keyboard. The
keyboard provides a familiar musical instrument ‘interface’ that produces a control voltage and trigger signal
whenever a key is pressed. The level of the control voltage signal is a function of which key is pressed - the
higher up on the keyboard you play, the higher the level of the control voltage.
The keyboard’s control voltage signal is commonly routed to the oscillators to control the pitch, and it can also
be routed to other voltage-controlled components like the filter, to vary the cutoff frequency. The keyboard
trigger signal is routed to the Envelope Generators to trigger the envelopes.
The second auxiliary component is the Envelope Generator, or EG. The
EG makes no sound by itself. Rather, it creates a time-varying control
voltage that is typically used to control the gain of the amplifier, or the
cutoff frequency of the filter. Many synthesizers, including the Voyager,
provide several EG’s for independent envelope control of the amplifier
and filter circuits.
The EG is triggered from a Gate signal that is generated every time a
key is pressed on the keyboard. Once triggered, as long as the key is
held down (i.e. the Gate signal is present), the EG envelope will evolve
according to the control settings.
The Voyager’s Envelope Generators have four stages that can be set individually:
Attack – The time to go from zero volts to the maximum voltage (the fade in time).
Decay – The time to go from the maximum voltage to the Sustain level.
Sustain – The maximum level of the envelope after completing the attack and decay stages (if the
key is held). If the sustain level is zero, the envelope consists of just the attack and decay
stages, and the Release control has no effect.
Release – The time to go back to zero volts when the key is released (the fade out time).
The last auxiliary component to mention is the Low Frequency Oscillator,
also known as the LFO. The LFO operates like the main oscillators in
almost all respects, but generally at a much lower frequency. LFO’s are
typically used to send modulation control signals to the main components.
For example, if you route a 6Hz LFO signal to an oscillator, it will produce
vibrato by varying the pitch of the oscillator. If you send that same LFO
signal to the amplifier, you’ll get tremolo. LFO’s are used to create cyclical
variations in the sound, making the sound more dynamic and interesting.
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So there you have it - the six basic components that make up a synthesizer based on the subtractive
synthesis model. Keep in mind that most ‘subtractive’ synthesizers often include more than one of each
component. This is especially true of the oscillators and envelope generators, but may also be true of filters,
amplifiers and LFO’s. For example, the Voyager OS has three oscillators, two filters, two amplifiers, an LFO,
two extensive modulation sections, and the Voyager’s third oscillator can act as an additional LFO. As you
would expect, synthesizers that offer more than one of each component provide a broader palette for
sound creation then those that don’t, and this generally result in sounds with a greater complexity, variation,
and depth. Add some solid programming and playing technique, and incredibly expressive musical sounds
can be achieved.
So what is the best way to program synthesizers effectively? The answer to that question could fill a book’s
worth of explanations and examples. Fortunately, a number of excellent books have been written on the
subject in recent years. Two such books, readily available, are:
“Power Tools for Synthesizer Programming” by Jim Aiken, available from Backbeat Books
“Analog Synthesis” by Reinhard Smitz, available from Wizoo Publications
As with all musical instruments, practice, exploration and experimentation are an important part of achieving great results. Spend a little time getting to know your new instrument - your efforts will be rewarded!
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Voyager OS User’s Manual - Appendices
Appendix E - Service and Support Information
Moog Limited Warranty
Moog Music warrants its produces to be free of defects in materials or workmanship and conforming to
specifications at the time of shipment for a period of one year from the date of purchase. During the warranty period, any defective products will be repaired or replaced, at Moog Music’s option, on a return-to-factory basis. This warranty covers defects that Moog Music determines are no fault of the user. In countries
outside of the USA, contact the Moog authorized distributor listed on our web site (
for service.
Returning your Product to Moog Music
You must obtain prior approval in the form of an RMA (Return Material Authorization) number from Moog
Music before returning any product. You can request an RMA number on-line using the ‘Product Register’
link on the Moog Music home page or call us at (828) 251-0090. The Voyager must be returned in the original inner packing including the foam inserts. The warranty will not be honored if the product is not properly
packed. Once packed, send the product to Moog Music Inc. with transportation and insurance charges paid.
What we will do
Once received, we will examine the product for any obvious signs of user abuse or damage as a result of
transport. If the product has been abused, damaged in transit, or is out of warranty, we will contact you with
an estimate of the repair cost.
How to initiate your warranty
Please initiate your warranty on-line at by clicking on the “Product Register” tab. If
you do not have web access, fill out the all the information on the included warranty card and mail to:
Moog Music, Inc.
Attn: New Product Registration
2004-E Riverside Dr.
Asheville, N.C. USA 28804
Appendix F - Caring for the Voyager Old School
Clean the Voyager with a soft, moist cloth only – do not use solvents or abrasive detergents. The finish of the
Voyager’s wood casing can be cleaned with a guitar polish, or a fine furniture polish. Heed the safety warnings at
the beginning of the manual. Don’t drop the unit. If you are shipping your Voyager to the factory for servicing,
we recommend using the original shipping carton, or an ATA approved Road Case. Shipping the Voyager in a
non-ATA or packaging other than the original carton will void the warranty. When setting up the Voyager, be
sure your stand or table is capable of holding at least 40lbs.
AN IMPORTANT NOTE ABOUT SAFETY: Do not open the chassis. There are no user
serviceable parts in the Voyager. Maintenance of the Voyager synthesizer should be referred
to qualified service personnel only.
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Voyager OS User’s Manual - Appendices
Appendix G - Accessories
To further enhance the functionality and appearance of the Minimoog Voyager OS, Moog Music offers the
following optional accessories. For complete information on everything listed here, including pricing and
ordering info, see your Moog dealer, or visit www.
EP2 Expression Pedal
The EP2 Expression Pedal is the finest expression pedal available. Its smooth action gives it the feel
musicians need for precise, playable control. The heavy construction (2.5 lbs) provides a solid feel, and an
output level control allows you to adjust the expression range of the pedal.
VX-351 CV Expander
The VX-351 Voyager CV Expander provides all the CV and Gate outputs of the Voyager OS on standard 1⁄4”
interface jacks. The VX-351 connects to the Voyager’s Output Accessory Port with the included detachable
cable, turning the Voyager OS into a semi-modular synthesizer.
CP-251 Control Voltage Processor
The CP-251 Control Voltage Processor offers a number CV processing options that can be used with any
Voyager, Moogerfooger analog effects module, or other voltage-controlled gear. The CP-251 provides a dual
waveform LFO, Noise Generator, Sample-and-Hold circuit, as well as two active attenuators, a Lag Processor,
a CV Mixer and a 4-way Multiple. This combination gives you ways to modify, mix, and distribute control
voltages to produce the incredible variety of sounds and effects that analog synthesizers are famous for.
VX-351 Rack Mount Kit
The VX-351 Rack Mount Kit allows you to mount any combination of two CV Expanders or CV Processors
into a standard 19” equipment rack. The kit occupies three rack spaces (51⁄4”H). All the necessary hardware
and instructions for assembly and installation is included.
Moog FS-1 Footswitch
The FS-1 Footswitch is a heavy-duty footswitch in a steel enclosure. The switch is a momentary, normally
closed type (press to break connection) which is compatible with any of the Voyager’s footswitch inputs
(Envelope Gate, LFO Sync, and Release) or the Moogerfooger MF-105 Tap Tempo input. It has a 6’ cable
with a 1⁄4” mono phone plug attached.
Molded ATA Case for Voyager
Protection when you’re on the road. The Voyager Molded Case is designed to meet ATA specifications, and
is custom fitted to the Voyager. With rugged, heavy-duty recessed wheels, and an internal compartment
large enough for storing cables and our new EP2 Expression Pedal, this case stands up to the most rigorous
touring schedules.
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Accessories (Con’t)
Voyager Gig Bag
For getting around town, the Voyager gig bag is a lightweight and convenient way to safely transport your
Voyager. The gig bag is made of heavy-duty nylon material, with double-stitched construction and a pouch
for your cables and accessories.
Dust Cover
Protect your investment when you’re not using it. The water repellent dust cover (with a drawstring) keeps
dust, pet hair, and other airborne debris from collecting on the Voyager.
Voyager Extended Warranty (available to US customers only)
The Extended Warranty adds three years to the Voyager’s standard one-year warranty, providing you a total
of four years of warranty protection.
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Voyager OS User’s Manual - Glossary
Here are a few key terms that cover the basics of sound generation as used in the Voyager OS synthesizer.
ADSR – Abbreviation for Attack, Decay, Sustain and Release, the four stages of an envelope control voltage.
Amplitude – The strength of a sound’s vibration measured in Decibels (dB). Amplitude corresponds to the
musical term Loudness.
Control Voltage – Control voltages (also called CVs) are used in analog synthesizers to affect changes in the
sound. In the case of pitch, pressing a key on the keyboard sends a control voltage that determines the
pitch of the oscillators. The keyboard CV is set to produce an equal tempered scale. As you play up the
keyboard, the CV is raised and the pitch increases. The pitch can also be affected by other CV sources,
like an LFO, often used to produce vibrato. Other major synthesizer components that respond to CV’s
include the filter (the higher the CV, the higher the filter cutoff frequency) and the amplifier (the higher
the CV, the higher the gain, or volume).
Envelope – An envelope describes the contours that affect the characteristics of a sound (pitch, tone and
volume) over time. For example, when a string is plucked, its amplitude is suddenly very loud, but then
dies out gradually. This describes the Volume envelope of the sound. We observe that the initial part of
the plucked sound is very bright, but then the brightness fades away. This describes the Tonal envelope
contour. We also hear the frequency of the sound go slightly higher when the string is plucked, and then
drop slightly as the note fades. This is the pitch envelope contour. A synthesizer can create these kinds
of changes by applying electrically generated envelopes to oscillators (affecting pitch), filters (affecting
tone) and amplifiers (affecting volume).
Envelope Generator – A circuit that generates an envelope signal. The envelope generator creates a timevarying signal that can be applied to any voltage-controlled circuit. The Envelope Generators in the
Voyager have four adjustable segments: Attack, Decay, Sustain and Release, also sometimes referred to as
ADSR. The Attack, Decay and Release segments are specified as time parameters, while the Sustain segment is a simply a level setting. Attack specifies the onset time of the envelope. For example, the sound
of a plucked string starts suddenly, meaning its volume envelope has a fast attack time. Decay specifies
how quickly the onset of the envelope fades into the sustained portion. Sustain is the level at which the
envelope sustains after the initial transient (the attack and decay portion). Finally, Release determines
how long the envelope takes to fade away. An Envelope Generator uses a trigger to start and stop the
ADSR envelope. This trigger is called a gate signal, and it’s produced whenever a key is pressed on the
keyboard. The gate signal turns on and stays on as long as a key is held down. When the key is released,
the gate signal turns off. When the gate is on, the Envelope Generator is triggered and the envelope
signal moves through the Attack and Decay segments and settles at the Sustain level as long as the gate
signal is on. When the gate goes off, the release segment of the envelope begins. A new gate signal
retriggers the Envelope Generator.
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Filter – A circuit that removes some frequencies and allows other frequencies to pass through the circuit.
A filter has a cutoff frequency that determines the point at which frequencies begin to be removed. A
lowpass filter is one in which frequencies above the cutoff frequency are removed and all frequencies
below the cutoff are passed through. A highpass filter is one in which frequencies below the cutoff
frequency are removed and frequencies above the cutoff are passed through. A bandpass filter has two
cutoff frequencies that define a frequency band, outside of which the frequencies are removed.
Frequency – The rate of vibration in sound measured in Hertz (Hz or cycles per second). The average hearing
range of the human ear is from 20 to 20,000 Hz. Frequency corresponds to the musical term ‘pitch’, but the
two terms are not always interchangeable. Frequency is an objective measurement of a sound, while pitch
is the perception of a sound, either low, high, or mid-ranged. A low frequency corresponds to a low-pitched
sound such as a bass; a high frequency sound corresponds to a high-pitched sound such as a piccolo. In
music, a change in pitch of one octave higher equals a doubling of the frequency.
Frequency Modulation – Also known as FM, Frequency Modulation describes the technique of using one
oscillator to modulate the frequency of another. In FM, the modulating oscillator is called the ‘modulator’,
while the other oscillator is known as the ‘carrier’. The carrier oscillator is the one you hear. When
the modulator frequency is very low (about 6Hz), the effect is described as vibrato. As the modulator
frequency is raised into the audio range, new modulation frequency components are created, and the effect
is perceived as adding new overtones to the carrier signal.
Glide – Also called portamento, is the slowing down of pitch changes as you play different notes on the
keyboard. Certain acoustic instruments, like the trombone or the violin, create this effect when the
performer adjusts the tubing or string length. The speed of the glide is called the glide rate. In synthesizers,
a Glide Rate control is used to determine the speed of the glide between notes.
Harmonic – A sound is made up of simple vibrations at many different frequencies (called harmonics) that give
a sound its particular character. This corresponds to the musical term timbre or tone color. A harmonic
sound, such as a vibrating string, is one in which the harmonics are mathematically related by what is called
the harmonic series. These sounds are typically pleasing to the ear and generally the consecutive vibrations
have the same characteristic shape or waveform. An inharmonic sound, such as a crash cymbal, is one in
which the harmonics are not mathematically related. Their waveforms look chaotic. White noise is an
inharmonic sound that contains equal amounts of all frequencies.
LED (Light Emitting Diode) – An electrical component that lights up when a voltage is applied.
Low Frequency Oscillator – Also called an LFO, this is a special type of oscillator that generates signals
primarily below the range of human hearing (generally below 20 Hz). LFOs are typically used as a
source of modulation. For instance, an LFO with a triangle waveform, set to about 6 Hz and modulating
the pitch of a VCO, results in vibrato. Changing the LFO waveform to a square wave will result in a trill.
An LFO modulating a VCA with a triangle wave creates tremolo.
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Mixer – A circuit for combining multiple sound sources or signals.
Modulation – Modulation is the use of a control voltage to shape a tone. Modulation has a source, a destination,
and an amount. This could be as simple as the filter cutoff of a VCF (a modulation destination) being
changed by the front panel cutoff control (the source), or as complex as mixing multiple CVs together to
modulate filter cutoff. Modulation is used in synthesis to create complex sounds and add variation.
Noise – A random audio signal having no fundamental, and where all the harmonics have equal strength (more
or less). Noise can be used as either an audio or modulation source. When used as an audio source, noise
can be used by itself to synthesize explosions or wind noises, or can be mixed with other waveforms to
create noise artifacts, such as breath sounds. When used as a modulation source, noise can introduce
instabilities to a sound, such as a ‘pitch cloud’ effect when noise modulates an oscillator. In the Voyager OS,
noise is available both as a sound source and a modulation source.
Oscillator – A circuit that electronically “vibrates”. When used as a sound source, an oscillator is the electronic
equivalent of a vibrating reed, or string. When amplified, an oscillator produces a pitched sound whose
frequency is determined by one or more control voltages. Changes to these voltages correspond to
changes in pitch. An oscillator’s vibration can have different shapes or waveforms, such as a triangle,
sawtooth, or square wave. The Voyager OS has three oscillators for generating sounds.
Pitch – The subjective perception of sound. A bass guitar generates low pitches, while a flute generates high
Pole (or poles) – A term referring to the design of a filter circuit. Each filter pole adds 6dB/Octave of
attenuation to the filter response, so while a single pole filter has a 6dB/Octave response, a 4-pole filter has
a 24dB/Octave response. The Voyager OS has two 4-pole filters.
Sample and Hold (S&H) – A circuit that generates a control voltage corresponding to the input signal at the
time a trigger or gate signal is received. Sample and hold circuits commonly employ white noise as a signal
source, taking periodic samples of this signal and holding that sample (a voltage level) until the next sample is
taken. Since the signal source is noise (a random audio signal), the output of the S&H circuit is also random.
The sampling interval is typically controlled by a low frequency oscillator (LFO). By adjusting the speed
of the LFO, the speed of the S&H circuit can be varied. The S&H output is available as a programmable
modulation source.
Sound – Audible vibrations of air pressure. For electronic sounds such as those produced by a synthesizer,
loudspeakers are used translate the electrical vibrations into the changes in air pressure which we perceive
as sound.
Subtractive synthesis – A method of creating tones using harmonically rich (bright) source material, and then
removing (or in some cases emphasizing) various frequency components to create the desired sound.
Synthesis – The generation of sound by electronic means, where the programmer or performer has the ability to
change the pitch, volume, timbre and articulation.
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Timbre – Pronounced ‘tamber’, it refers to the quality of a sound by its overtones. An unprocessed sawtooth
wave has a bright timbre, while a triangle wave has a mellow timbre.
Tremolo – Technically a form of low frequency amplitude modulation, tremolo is a smooth audible pulsing of
volume. In synthesizers, tremolo is produced when a 5-6Hz LFO triangle or sine wave signal is applied to a
voltage controlled amplifier.
Waveform – The shape of an oscillator’s vibration. This shape determines its timbre. Commonly used
waveforms in subtractive synthesis include sawtooth, triangle, square, or rectangular. Different waveforms
have different timbres. A sawtooth has the greatest number of harmonics, and sounds bright and buzzy.
A square wave has only odd harmonics, and sounds bright but hollow, like a clarinet. A rectangular wave
can vary in shape, but typically has a bright but thin sound, and a triangle wave’s harmonics are so low in
amplitude that it sounds muted and flutelike.
VCA – Short for Voltage Controlled Amplifier, a VCA is an amplifier circuit where the gain is a function of the
control voltage. In the Voyager, the VCA is paired with the Volume Envelope Generator to specify the
articulation of a sound. Another CV source for the VCA in the Voyager is the Volume CV Input.
VCF – Short for Voltage Controlled Filter, a VCF is a filter circuit where the filter cutoff frequency is a function of
the control voltage. A VCF is used to control the timbre of a sound. In the Voyager, the VCF is paired with
the Filter Envelope Generator for dynamic control. Other CV sources for the VCF include the Keyboard
Amount, Modulation Matrix and Filter CV Input.
VCO – Short for Voltage Controlled Oscillator, a VCO is an oscillator circuit where the oscillator frequency is a
function of the control voltage. In the Voyager, the VCO is primarily controlled from the keyboard. Other
CV sources for the VCO include the Modulation Matrix, and Pitch CV Input.
Vibrato – Technically a very low frequency modulation, vibrato is a smooth, mild pitch warble. In synthesizers,
vibrato is produced when a 5-6Hz LFO triangle or sine wave signal is applied to a voltage controlled
oscillator, causing the pitch to deviate slightly above and below the base frequency.
Voyager OS – A monophonic analog performance synthesizer that is a successor to the classic Minimoog
Model D.
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Patch Templates
Just like the original Minimoog, the best way to record your patches for later recall is to document them using patch templates. A blank patch template page is provided here for you to copy and use to record your
own sonic creations.
To help get you started on your musical explorations, here are a couple of sample patches of typical
Minimoog sounds. You can use them as-is, or as starting points for creating new sounds. For more patches,
visit the Voyager OS section on the Moog Music web site (
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Minimoog Voyager Old School User’s Manual
© Moog Music 2008, all rights reserved
Text and illustrations by Greg Kist, Steve Dunnington
and the resources of Moog Music.
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