Electro-Harmonix MOD REX User manual

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MOD REX
Polyrhythmic Modulator
Congratulations on your purchase of the Electro-Harmonix Mod Rex Polyrhythmic
Modulator. The Mod Rex is a powerful modulation tool designed for multiple
instruments and uses and is equipped with many features including:
•Up to 4 simultaneous modulation sections synced together in time
•MOD section offers choice of Vibrato Flanger Chorus or Phaser effect
•Standalone Tremolo Modulated Panning and Modulated Filter sections
•9 tempo subdivision options for each modulation section
•4 LFO shape options for each modulation section
•100 storable presets
•Full stereo input and output
•Tap Tempo
•Tempo-Sync to an external device with MIDI Clock or an external pulse clock
•Full MIDI control of all parameters and recalling of presets
•External expression pedal input
•External foot controller input to bank up and down presets
•9.6VDC/200mA power supply included
WARNING: Your Mod Rex comes equipped with an Electro-Harmonix .6VDC-200mA
power supply. The Mod Rex requires 100mA at VDC with a center negative plug and
does not accept batteries. Using the wrong adapter may damage your unit and void the
warranty. Please do not exceed 10.5VDC on the power plug.

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Overview: What Is The Mod Rex? – page 3
Co trol Diagram – page 4
Top Pa el Display Scree – page 5
Divisions Display Mode – page 5
Tempo Display Mode – page 6
Presets Display Mode – page 6
Modulatio Parameters – page 7
Divisions – page 7
Tempo and Rate Knob Mode – page 7
LFO Shapes – page 7
MOD Section Parameters – page 8
TREM Section Parameters – page 8
PAN Section Parameters – page 9
FILTER Section Parameters – page 9
Volume – page 9
Signal Path – page 9
Presets – page 10
Loading a Preset – page 10
Saving a Preset – page 10
Blank Presets – page 11
LOCK Button – page 11
What You See Is What You Get Mode – page 11
Factory Reset – page 12
Footswitches a d Jacks – page 13
Bypass – page 13
Tap Tempo – page 13
Power – page 13
Input and Output – page 13
Expression Pedal – page 14
External Clock and Foot Controller – page 14
MIDI a d the Mod Rex – page 15
MIDI Tempo Sync – page 15
MIDI Program and Control Change Messages – page 15
MIDI CC Message Assignments – page 16
Factory Presets’ Parameter List – page 17
Warra ty I formatio – page 19

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Overview: What Is The Mod Rex?
The Mod Rex is a powerful modulation unit that gives you a massive toolbox of
modulation options. At the core of the Mod Rex are its four modulation sections:
MOD: A choice of a vibrato flanger chorus or phaser effect
TREM: A tremolo effect
PAN: A modulated panning effect
FILTER: A choice of a modulated low-pass high-pass or band-pass filter effect
Any of these sections can be on individually and any combination of them can be on
simultaneously. All four are linked to the same tempo in beats per minute (BPM) but
each one can independently have one of nine tempo subdivision options. Each
modulation section has multiple parameters to fine tune your sound including four
modulation LFO shape options: rising-sawtooth triangle falling-sawtooth and square.
You can have a vibrato effect going at exactly twice the rate as a simultaneous tremolo
effect. Have a phaser on the whole note while simultaneously having a tremolo on the
quarter note and a modulated low-pass filter on the eighth note. Create a poly-
rhythmic effect with a quarter note tremolo and a dotted-quarter note modulated filter.
These are merely a handful of examples of the nearly limitless possibilities with the Mod
Rex.
In addition to these rhythmic-combination effects you can also use the Mod Rex as a
more traditional modulation effect just with several non-traditional options. Apply
falling-sawtooth flanger blasts or use a tap-tempo stereo phaser. MIDI sync external
tracks and apply a rising-sawtooth tremolo for a side-chaining effect.
The bottom left LED always blinks based on the quarter note. The tempo can be set
manually with the tempo knob via tap-tempo or synced to an external device via MIDI
clock or an external pulse clock.
The Mod Rex is designed to maximize your ability to precisely apply rhythmic effects to
whatever you plug into it. Its tap-tempo allows you to continue to play while tapping as
all modulations (including any with uneven subdivisions) adjust fluidly to your tapped
tempo without resetting upon each tap. Plug a drum machine sequencer or an audio
interface from a laptop into the Mod Rex and sync the tempo with MIDI Clock to create
perfectly-in-sync rhythmic effects.
The Mod Rex can store and recall 100 presets to maximize your ability to create and use
a variety of effects. It features full stereo in and out. An external expression pedal or
foot controller can be used to control the Mod Rex. The unit is fully MIDI controllable
and integrates seamlessly into any modern MIDI setup. These options make the Mod
Rex the ultimate rhythmic modulation machine.

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1-VOL controls master volume of the effect (page 9)
2-Digit Display and Display State LEDs (page 5)
3-PRESET SELECT/STORE used to store and recall presets (page 10)
4-TEMPO used to manually set the master modulation tempo/rate (page 7)
5-LOCK used to maintain current tempo upon recalling a preset (page 11)
6-MOD Section section with option of four different modulation effects (page 8)
7-TREM Section section controlling a tremolo effect (page 8)
8-PAN Section section controlling a modulated panning effect (page 9)
9-FILTER Section section controlling a modulated filter (page 9)
10-Shape LEDs display LFO shape for one of the four sections (page 7)
11-Shape SELECT button used to change LFO shape of a given section (page 7)
12-BYPASS switch between effect mode and buffered bypass mode (page 13)
13-Status LED shows if the pedal is in effect or bypass mode (page 13)
14-TAP tap in quarter notes to set master modulation tempo (page 13)
15-Rate LED shows speed of current master tempo/rate (page 13)
16-MONO/L Input input for mono signal or left channel of stereo signal (page 13)
17-R Input input for right channel of stereo signal (page 13)
18-EXP input for expression pedal (page 14)
19-MONO/L Output output for mono signal or left channel of stereo signal (page 13)
20-R Output output for right channel of stereo signal (page 13)
21-CLK/FC input for external pulse clock or foot controller (page 14)
22-MIDI IN input for MIDI signals (page 15)
23-Power Jack power input 9V DC center negative (page 13)

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Top Pa el Display Scree
At the center of the Mod Rex’s user interface is the four-digit display screen at the top
of the unit. This display screen has three main modes each displaying different
information. The three modes are DIVISIONS TEMPO and PRESET. One of the three
labeled LEDs to the left of the display screen will be lit to show you which of these three
modes you are in. Switching between these three modes is quick and intuitive.
Note: There are a handful of situations where all three of these LEDs will be lit and the four-digit
display is showing you something different these situations will be discussed later in the manual.
DIVISIONS DISPLAY MODE
In DIVISIONS display mode each digit independently represents the current tempo
subdivision of one of the four modulation sections. From left to right MOD TREM
PAN and FILTER. To switch into DIVISIONS display mode simply begin turning or press
and release one of the four DIVISION knobs. There are ten possible settings for each
digit:
0 = Modulation section is off
1 = Tempo subdivision is set to a whole note
2 = Tempo subdivision is set to a half note
3 = Tempo subdivision is set to a dotted quarter note
4 = Tempo subdivision is set to a quarter note
5 = Tempo subdivision is set to a quarter note triplet
6 = Tempo subdivision is set to a dotted eighth note
7 = Tempo subdivision is set to an eighth note
8 = Tempo subdivision is set to an eighth note triplet
9 = Tempo subdivision is set to a sixteenth note
Consider the below example:
In this example the MOD section has a tempo subdivision of a whole note the TREM
section has a subdivision of a quarter note the PAN section is off and the FILTER section
has a subdivision of an eight note triplet.
The divisions are changed by turning that section’s DIVISION knob. As you increase or
decrease the number that digit will blink. To set the new division once you get to the
blinking number you want press and release that DIVISION knob to set the new division.
The digit will stop blinking and the new division is set.

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TEMPO DISPLAY MODE
In TEMPO display mode the display shows the current tempo in beats per minute
(BPM). To switch to TEMPO display mode simply start rotating or press and release the
TEMPO knob. The tempo can be set manually by rotating the TEMPO knob. The tempo
can also be set by tap tempo or an external device. In these cases in TEMPO display
mode the tempo shown is rounded to the nearest BPM with no decimal places but the
actual modulation will be perfectly in sync to the external source even if it has a
fractional component. The Mod Rex has a minimum tempo of 10 BPM and a maximum
tempo of 500 BPM.
Note: In some scenarios when syncing the tempo with MIDI Clock the tempo displayed on the Mod
Rex may be off by one BPM or may jump between a couple of numbers. In these scenarios the
Mod Rex is still perfectly in sync with the external device.
PRESET DISPLAY MODE
In PRESET display mode the current preset is displayed from 1 to 100. To switch to
PRESET display mode simply start rotating or press and release the PRESET
SELECT/STORE knob to the right of the display.
Similarly to changing a modulation section’s division as you rotate the PRESET
SELECT/STORE knob the display will blink. Once you get to the number you want press
and release (don’t hold down) the PRESET SELECT/STORE knob to load that preset.
In PRESET display mode you may see a dash in the first digit place. This indicates that
the current preset number displayed does not actually have a preset saved to it yet.
Also in PRESET display mode the right-most decimal place may be lit. This indicates that
since the displayed preset was loaded some parameters have changed and the preset
has not been resaved with the new parameters.
For more information on recalling and saving presets please see the Presets section on
page 10.

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Modulatio Parameters
Each of the four modulation sections has its own set of parameters neatly grouped into
sections. The Tempo setting affects all four sections. While the four sections share one
bank of yellow LFO shape LEDs each section can independently be assigned one of the
four shape options.
DIVISIONS
Each modulation section has a DIVISION knob to set its tempo division and to
activate/deactivate the section in general (a division of 0 has the section inactive).
Divisions are explained in depth in the DIVISIONS DISPLAY MODE section on page 5.
TEMPO AND RATE KNOB MODE
The master tempo can be set manually by rotating the TEMPO knob in either direction.
It can also be set via tap tempo or an external device. These situations are good for
creating precise rhythmic based effects. If you want to use the Mod Rex as a more
traditional modulation pedal (less concerned with the exact modulation rate in BPM)
you can switch the TEMPO knob into Rate Knob Mode. In Rate Knob Mode the tempo
increases/decreases much more quickly as you turn the knob in either direction. You
have less precise control over the tempo but the feel of the knob much more closely
resembles a traditional rate knob.
To switch into Rate Knob Mode hold down the TEMPO knob until the yellow TEMPO
LED to the left of the display starts to blink. Release the TEMPO knob and you are now
in Rate Knob Mode. Hold the TEMPO knob again until the yellow LED is solid to go back
to normal mode.
LFO SHAPES
All four modulation sections share one bank of four yellow LFO shape LEDs underneath
the display. To see the current LFO shape of a specific section hold down that section’s
SHAPE button. One of those four yellow LEDs will light. To change a specific section’s
LFO shape while holding down that section’s SHAPE button toggle the SELECT button
by the bank of yellow LEDs. The four LFO shape options are:
RISING SAWTOOTH: With this shape over one modulation cycle (based on that section’s
division) a modulation will slowly rise from its minimum point to its maximum point and
immediately reset to its minimum point upon the next modulation cycle. This setting is
good for creating effects similar to a side-chaining effect or a reverse effect.
TRIANGLE: This is the most traditional LFO shape. In this setting over one modulation
cycle the modulation smoothly moves back and forth between its minimum and
maximum point.

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FALLING SAWTOOTH: This shape is the opposite of the rising sawtooth. Over one
modulation cycle a modulation slowly falls from its maximum point to its minimum
point and immediately resets to its maximum upon the next modulation cycle. This
setting is good for creating sharp rhythmic effects.
SQUARE: With this shape over one modulation cycle the modulation alternates directly
between its maximum point and its minimum point with no smooth transition between.
This setting is good for creating very choppy effects.
MOD SECTION
The MOD section controls parameters for one of four possible effects selectable via the
TYPE button. The four MOD options are:
Vibrato: A modulated pitch effect
Flanger: A rich resonant sweeping effect
Chorus: A lush warbling doubling effect
Phaser: A modulated phase shifting effect
Press the TYPE button to toggle through the four MOD section effects VIB (Vibrato) FLN
(Flanger) CHR (Chorus) and PHS (Phaser).
DEPTH: The DEPTH knob sets the amount of the effect. In Vibrato mode it sets the
maximum amount of pitch shifting. In Flanger and Chorus mode it sets the maximum
depth of the effect. In Phaser mode it sets the size of the LFO or the amount of phase
modulation.
FEEDBACK: The FEEDBACK knob only has effect in Flanger and Phaser modes. It
increases the amount of feedback which emphasizes the resonance of the effect.
R INV: The R INV button is used in stereo operation. With the button pressed in it
inverts the LFO in the right channel. This is great when using a mono in/stereo out
setup to give a mono input a stereoized effect.
TREM SECTION
The TREM section controls parameters for a tremolo effect modulating the volume of
your signal.
DEPTH: The DEPTH knob sets the depth of the tremolo effect. With maximum depth the
signal will modulate all the way to no volume (muted). With less depth the effect won’t
modulate as far and the tremolo effect will be more subtle.

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PAN SECTION
The PAN section when in stereo operation modulates your signal between the left and
right output. In mono operation in effect the PAN section acts as another TREM
section but with the wave shapes all inverted.
DEPTH: The depth control affects the spread of the modulation. At maximum your
signal will modulate from 100% in the left channel to 100% in the right channel. As you
bring DEPTH down the modulation spread is lessened or in effect “pulled back” into
the center of the stereo field.
FILTER SECTION
The FILTER section offers three modulated filters modes:
Low Pass Filter (LPF): Frequencies above a modulated cutoff point are cut
High Pass Filter (HPF): Frequencies below a modulated cutoff point are cut
Band Pass Filter (BPF): Frequencies above and below a modulated center point are cut
MODE: The MODE button toggles through the three filter modes.
DEPTH: The DEPTH knob sets the high point of the cutoff modulation
RES: The RESONANCE knob increases the emphasis on frequencies right at the cutoff
point of the filter emphasizing the sweeping effect. In BPF mode increasing the
resonance also shrinks the bandwidth of the filter meaning more frequencies above
and below the center point are cut.
R INV: The R INV button is used in stereo operation. With the button pressed in it
inverts the LFO in the right channel. This is great when using a mono in/stereo out
setup to give a mono input a stereoized effect.
VOLUME
The VOL knob in the top left corner controls the master output volume of the effect.
This master volume setting is saved and recalled via presets.
SIGNAL PATH
When all four sections are active the signal path is FILTER -> MOD -> TREM -> PAN.

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Presets
The Mod Rex can store and recall up to 100 presets. Upon powering up the Mod Rex
will load the last used preset.
LOADING A PRESET
To load a preset start rotating the PRESET SELECT/STORE knob. As you rotate through
the preset number shown in the display will blink. To select that preset press and
release (don’t hold down) the PRESET SELECT/STORE knob.
Upon loading a preset all current parameters will be overwritten by those saved within
that preset. For parameters such as Tempo Divisions LFO Shapes MOD/FILTER type
and R-INV the digit display/LEDs will automatically display the new setting. For the
seven parameters controlled by physical fluid knobs (VOL all four DEPTH controls
FEEDBACK and RES) the setting recalled with the preset will overtake the physical
position of the knob. After loading a preset once you rotate any of those seven knobs
that parameter will jump to the physical position of that knob.
After loading a preset if any parameter is changed in PRESET display mode the right-
most decimal place will be lit to signify a parameter is different than in the saved preset.
Any changes made after loading the preset won’t be remembered upon reloading that
preset (or powering the unit off and back on) unless that preset is re-saved with the new
settings.
SAVING A PRESET
To save your current setting as a preset while in PRESET display mode toggle to the
preset number you want to save to. Hold down the PRESET SELECT/STORE knob until
the blue PRESET LED to the left of the display begins to blink. Release the knob and the
current settings are now stored as a preset in that number slot.
As you rotate through preset numbers the display blinks unless it is displaying the
currently loaded preset number. If when saving a preset you are simply updating the
currently loaded preset (as in want to save it to the same preset number) while in
PRESET display mode simply hold down the PRESET SELECT/STORE knob until the blue
PRESET LED begins to blink. Release the knob and the preset is updated with your
current settings. If the right-most decimal place was lit signaling a changed parameter
upon updating the preset it should go off.
NOTE: If while in PRESET display mode you press and release quickly the PRESET SELECT/STORE
knob that preset number will be re-loaded and any changes you made since you last recalled that
preset will be lost.