Synthesis Technology MOTM-650 User manual

MOTM-650 4 Channel
MIDICV Converter
User’s Guide
Firmware Version 1.4
Synthesis Technology
6625 Quail Ridge Dr.
Fort Worth, TX 76180
[phone]
www.synthtech.com
October, 2011

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GENERAL INFORMATION
Thank you for purchasing the MOTM-650 4CH MIDI-CV Converter. If you have any issues
concerning the use of the MOTM-650, please contact us at (888) 818-MOTM or by email:
[email protected]
TROUBLESHOOTING GUIDE
If your MOTM-650 does not work as expected, keep in mind the MOTM-650 is a complex
modal device, and more often than not, problems encountered are related to a higher level
feature set to an unexpected value.
THEORY OF OPERATION
The MOTM-650’s functionality is provided by an Atmel AT89C51RD2 embedded CPU, a
version of the 8051. Its built-in UART is used to send and receive MIDI data, and its
internal clock is used to drive the 650’s two arpeggiators. Its internal FLASH memory
makes it possible to update the chip’s firmware via MIDI. The chip has numerous inputs
and outputs which are used to read the front panel buttons and the clock input, to control
the LCD, and to drive the gate outputs & LEDs. The CPU also has an SPI interface which
is used to talk to the two analog-to-digital converters (ADCs).
The four main CV outputs are provided by an AD5541 16-bit ADC. Its output is fed into a
DG408 4-channel analog demultiplexer, which provides four control voltage (CV) outputs
from the in turn feeds four AD822 dual op-amps. The AD822s sample and hold the CVs
between updates from the CPU, which occur once every millisecond.
The eight velocity and auxiliary CV outputs are provided by a TLV5608 8-channel 10-bit
ADC. Because this chip has eight latching DACs, it does not require a demultiplexer or
sample-and-hold circuitry. Its outputs are buffered by two TL074 quad op-amps.
TERMINOLOGY AND SYMBOLS
Settings are module features which can be changed using the MOTM-650’s front panel user
interface or via MIDI System Exclusive (SysEx) or Continuous Controller (CC) messages.
Options are the various choices that can be made for each setting.
Voices are the 4 vertical groups of CV, GATE, VEL, & AUX output jacks, which are usually
associated with one of the current MIDI Note On messages.
BOLD fonts like this in the middle of text indicate a button, jack, or LED legend on the
MOTM-650’s front panel.
Bold fonts like this indicate the name of a Setting or Option.
Fonts like this show what appears on the MOTM-650’s LCD.

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FRONT PANEL
The MOTM-650’s front panel looks like this:

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From top to bottom:
LCD – This 8 character by 2 line LCD is the primary user interface for settings, status, and
other MOTM-650 related information. The LCD backlight can be controlled via global
settings.
MIDI – Indicates MIDI activity on input to the MOTM-650. This is an indicator of all MIDI
data sent to the MOTM-650’s MIDI IN – not just MIDI data bound for the MOTM-650. Note
that this LED is lit by the MOTM-650’s processor, not directly from MIDI data pin.
V1-V4 LEDs – These LEDs indicate when a voice’s gate is either on (lit) or off (not lit). If a
voice is set as an S Trigger, an LED on indicates the gate is shorted and off indicates the
gate is open.
BEAT LED – This LED will blink at the rate of the clock source.
ESC – The ESCAPE button is used to either cancel a setting change, or move to a higher
level function. Just remember, when in doubt, press ESC.
ENTER – The ENTER button is used to accept a setting change, step to a lower level
function, or confirm that a changed setting is desired.
DEC / INC – The DECREMENT and INCREMENT buttons are used to step through the
menu options and change settings. In some contexts, holding down either button will cause
an accelerated repeat of either button, which makes changes happen more quickly (much
like the key repeat on a computer keyboard).
MIDI IN – The MOTM-650’s MIDI input.
MIDI OUT – The MOTM-650’s MIDI output.
EXT CLK – External clock pulse input for external clocking of the MOTM-650.
AUX 1-4 – 10 Bit assignable auxiliary outputs – one for each voice. Each output has its own
settings and menus to control them. See the Voice Group Settings section of this manual
for information on their operation.
VEL 1-4 – 10 Bit velocity output or trigger output. The function of these jacks is dependent
on their Voice Group Setting.
GATE 1-4 – Gates for each of the individual voices. These directly track the Voice 1-4 LEDs
as described above.
CV 1-4 – 16 Bit control voltage outputs, used to convert MIDI note data to control voltages.
They are usually connected directly to VCOs, but can be used for any module that needs a
highly accurate control voltage.

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USER INTERFACE INTRODUCTION
Before getting in to the specifics of the MOTM-650’s feature set, let’s get comfortable using
the MOTM-650’s user interface. Switch on the MOTM-650. The LCD will light up and
indicate the MOTM-650 and its firmware version number, followed by a screen looking
something like this:
G1 CH=1
Solo
For now, ignore its meaning – press ENTER. The MOTM-650 will display this:
Global
Settings
Press the DEC / INC buttons to scroll through the top-level user functions. INC moves
forward and DEC moves backward through the list of top-level functions. Notice that
eventually the options will loop back around to Global Settings.
With INC or DEC, select Global Settings and press ENTER. The LCD will show:
VGrpType
4
Get comfortable scrolling through the Global Settings by using INC or DEC, and when
finished, press ESC. This backs the display out to the top-level menu, and will show:
Global
Settings
This is how the entire menu system is structured – a top level of function categories,
followed by a single level of settings or actions. And pressing ESC at any time will back up
one level.
Okay, now that you have a basic understanding of top-level/sub-level menus, get the screen
back to Global Settings, and press ENTER to display the first setting, VGrpType. For the
time being, let’s ignore what this means, and use the INC or DEC buttons until the display
shows:
Clock
Internal
The display will be steady. Press ENTER – notice that Internal begins to flash. This
indicates that the setting can be changed. Press INC or DEC to scroll through INTERNAL,

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MIDI Clk, Ext. Reg, or Ext. Irr. Select MIDI CLK, and press ENTER. The display should
show:
Clock
MID IClk
…and MIDI Clk should be steady. You’ve just changed the clock source from the 650’s
internal clock to MIDI clock. This is how any setting is changed – press ENTER to edit the
setting, use INC or DEC to choose an option or set the value, and press ENTER again to tell
the MOTM-650 to store the change.
Let’s try one more aspect of the MOTM-650’s user interface – With the display showing
Clock MIDI Clk, press ENTER again. MIDI Clk will begin to flash. Use INC or DEC to
select Internal on the display, but instead of pressing ENTER, press ESC instead. The
display will show:
Clock
MID IClk
This allows the user to back out of a change before it becomes permanent, and the setting
will be set back to whatever it was before the change was made.
In short, press ENTER to edit a setting, change the setting with INC or DEC, then press
either ENTER to select the change or ESC to cancel it. All the settings work this way!
Keep in mind that the entire MOTM-650’s user interface works just as above, regardless of
function or feature.
Note that all MOTM-650 setting changes can be transmitted via MIDI. This is useful when
a live performance is being done and a recording of all front panel changes is desired.
All settings are stored in internal flash memory. Once a setting change is made, it’s saved
across power cycles. The MOTM-650’s entire active state is saved in nonvolatile memory.

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DETAILED FEATURE DESCRIPTION
Top-level Function Categories
The MOTM-650’s functionality can be broken up into four categories:
Global Settings – Global settings apply to the MOTM-650 as a whole. Most global settings
apply to all voice groups simultaneously. These features include, but are not limited to,
clock source, tuning tables, tempo, voice group configuration, etc…
Voice Group Settings – A voice group is a logical grouping of voices that share the same
settings, including MIDI channel.
Arpeggiator Settings – The MOTM-650 has two arpeggiators, each of which can be
assigned to a voice group, no voice group, or both to the same voice group. Arpeggiators use
settings from global settings (such as clocking) and have their own settings available.
Module Actions – These are one-shot actions that perform various functions, such as
dumping patches, storing patches, etc… They are not settings as in global, voice group, or
arpeggiator categories, rather just instructions to perform a specific action.
Note: Settings may appear and disappear in the menus depending upon how the MOTM-
650’s options are set. For example, setting the Clock Source to MIDI Clock will cause the
Internal Clock BPM setting to disappear from the Global Settings menu. There are only
a few cases where this occurs, and it’s done to ensure that only the settings that will have
an effect on the MOTM-650’s operation are visible at any given time. If one of the expected
setting doesn’t appear, check the MOTM-650 Menu Chart in Appendix A to see if another
setting controls whether or not it appears.
Global Settings
The MOTM-650 has the following settings with a global effect:
Voice Group Type
Velocity Scale
Trigger Pulse Width
Solo Note Priority
Tuning Table
Note Inversion
Backlight Intensity
System Status
SysEx Device ID
Global Control MIDI Channel
Patch Reception
Clock Source
MIDI Clock Output
Internal Clock BPM

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Return to the menu’s top-level by pressing ESC a couple of times, then press INC until the
LCD displays:
Global
Settings
Press ENTER, and the first setting will be displayed – the Voice Group Type (abbreviated
as VGrpType).
Note::In reviewing the settings and their associated options, each setting will be presented
in the center of the page abbreviated as it appears on the LCD, along with its default option.
The full name and description of the setting will follow, and then each option or group of
options will be explained.
VGrpType
4
The Voice Group Type setting sets the number and configuration of voice groups
available. At this point, you may be wondering – what is a voice group? A voice group is a
logical grouping of the MOTM-650’s four voices, allowing each voice to either share control
settings or have separate settings, depending on how the voices are being used. For
example, if you have several VCOs and want to use them polyphonically, you’ll probably
want to group them together so they have the same settings. If, on the other hand, you’re
using your MOTM-650 to control four monophonic synth voices, it may make sense to have
different settings for each voice. The Voice Group Type setting allows the following
combinations of voice groups:
4- 1 Voice Group with all 4 voices.
2/2 - 2 Voice Groups with 2 voices per group
1/1/1/1 - 4 Voice Groups with 1 voice per group
You will probably only change the Voice Group Type when setting up a new patch, as it
radically changes the way that MIDI data is interpreted and routed to the MOTM-650’s 16
CV outputs.
For now, leave the Voice Group Type set to 4. The settings available to each voice group
will be explained later.

VelScale
_4Volts
The Velocity Scale setting sets the output scaling of the VEL outputs when they are set to
output velocity. It can be set to output 1, 2, 4, or 8Volts when a velocity of 127 is received,
and will be scaled between 0 volts and full scale in proportion to other velocity values.
Trig PW
10ms
The Pulse Width setting sets the width in milliseconds of the GATE outputs when they are
set to Shorting Trigger mode, and the VEL outputs when they are set to Trigger mode.
The width can be set to 1, 10, or 100 ms, with an accuracy of 2 ms.
Priority
LastNote
The Solo Note Priority setting controls which note is voiced when the Voice Allocation
Mode is set to one of the solo modes and several notes are held.
LastNote
Last Note priority uses the solo voice(s) to sound the last note played. Last note is how
most monosynths operate.
Low Note
Low Note voices the lowest note still held. This is useful for playing the low note of a
chord to double the bassline.
HighNote
High Note voices the highest note still held. This is best used for playing a solo using the
high note of a chord.

TunTable
__12 Tone_
The Tuning Table setting sets the tuning table used to map the MIDI note values to the
CV output voltages. There are 16 tuning memories to choose from. These are programmed
at the factory with 16 tunings, which were selected by Robert Rich (see Appendix B for
Robert’s description of each tuning). All but the first Tuning Table (standard Equal
Temperament) can be overwritten by sending MIDI Tuning Standard messages to the
MOTM-650. Once overwritten, they can only be restored by sending the 650 a tuning dump
with the correct tuning data.
The default tunings are as follows:
Name Memory Description
12 Tone 1 12 Tone Equal Temperament
HrmA1 -60 2 Harmonic Series
HrmA1 -12T 3 Carlos Harmonic 12 Tone
Meantone 4Meantone Temperament
1/4TonET 5 ¼ Tone Equal Temperament
19TonET 6 19 Tone Equal Temperament
31TonET 7 31 Tone Equal Temperament
PythagoC 8 Pythagorean C
JIA7/5D# 9 Just Intonation in A w/ 7-limit Tritone at D#
3 -5LattA 10 3-5 Lattice in A
3 -7LattA 11 3-7 Lattice in A
7LimBlkC 12 Other Music 7-limit Black Keys in C
PelSlenB 13 Dan Schmidt Pelog/Slendro
JIMajYam 14 Yamaha Just Intonation Major C
JIMinYam 15 Yamaha Just Intonation Minor C
Partch11 16 Harry Partch 11-Limit 43 Note Just Intonation
Note Inv
_Off
The Note Inversion setting turns note inversion On or Off.

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Off
With inversion Off , the keyboard plays normally.
On
When inversion is On, the note numbers are reversed, so that Note #0 becomes #127, #1
becomes #126, etc. This is useful for playing your keyboard backwards like Joe Zawinul.
Backlght
Auto
The Backlight setting controls the output level of the LCD’s backlight. It can be set to Off,
Dim, Normal, Bright, and Auto. Auto will turn the backlight on whenever a button is
pressed, leave it on as long as the setting is being changed, then turn it off a few seconds
the last button is released.
Status
Show= On
The System Status setting turns the display of status updates On or Off.
On
When system status is On, status updates are shown whenever the LCD is idle for a few
seconds. The status update shows the current MIDI channel and voice allocation mode
setting for each voice group. If more than one voice group is enabled, then the updates
rotate through each voice group’s status every few seconds.
Off
With system status is Off , no status updates are shown.
SysexDev
ID=Globl
The SysEx Device ID setting selects the device ID used in system exclusive messages.
ID=Globl
When the ID is set to Global, the 650 will process all valid SysEx messages it receives. It
will also transmit messages using the Global ID, which will be processed by any other 650s
that receive them.

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ID=0
When the SysEx Device ID is set to an integer from 0 to 15, the 650 will transmit and
receive SysEx messages using this ID. Messages received with other IDs will be ignored,
unless it’s the Global ID.
Disabled
When set to Disabled, the 650 will ignore SysEx messages.
CtrlM ID I
Chan=16_
The Global Control MIDI Channel setting sets the MIDI channel for MIDI continuous
controller (CC) messages to control Global Settings. This can be any channel from 1 to
16. See the MIDI Implementation Table in Appendix C for a definition of each CC message.
Note: Because each each voice group can have its own MIDI channel setting, notes sent to
the Global Control MIDI Channel will only be played if there is a voice group whose
MIDI Channel is set to that same channel.
Patch RX
Disabled
The Patch Reception setting enables or disables the reception of patch data using MIDI
CC messages. It does not affect the reception of SysEx patch data. See the Module
Actions section for a description of patches.
Clock_
Internal
The Clock Source setting selects the clock source for the arpeggiators.
Internal
Internal uses the clock of the 650’s CPU to generate a clock signal for the arpeggiator.
MID IClk
MIDI Clock uses clock messages received on the MIDI IN to sync the arpeggiators to. If a
stop signal is received, or if the clock messages drop out, then the 650 will generate an
internal clock at the last tempo received, so that a clock doesn’t have to be running to try
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Ext.Reg.
External Regular syncs the arpeggiators to the rising edge of CV pulses on the EXT CLK
input. This option requires a regular pulse for best results when MIDI Clock Transmit is
enabled, or when using a Clock Divisor / Multiplier setting other than X1. When the
clock pulse stops, the 650 will generate an internal clock at the last tempo received, just as
it does with the MIDI Clock setting.
Ext. Irr.
External Irregular also syncs the arpeggiators to the rising edge of CV pulses on the EXT
CLK input, but it does not allow the additional clocking features that the other clock sources
do. It plays one note per clock pulse, and is best used when the clock source is irregular.
MID IClk
Transmit
The MIDI Clock Output setting is only displayed when the Clock Source is set to
Internal, or to External Regular.
Transmit
The Transmit option turns MIDI clock transmission on whenever one of the arpeggiators
is enabled. Whenever Transmit, selected, a Start command will be sent from the MIDI OUT
and Clock commands will be sent regularly. This option is useful for synchronizing
sequencers and drum machines to the 650’s arpeggiators.
Off
The Off option disables MIDI clock transmission.
IClk BPM
_120.0
The Internal Clock BPM setting is only displayed when the Clock Source is set to
Internal. It sets the tempo of the internal clock to one of 128 tempos, ranging from 60
beats per minute (BPM) to 238 beats per minute. At the middle of the range, the resolution
is .5 BPM; at the extremes it is 2 BPM.

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Voice Group Settings
As explained previously, the MOTM-650 can have up to 4 logical groups of voices, as
determined by the global Voice Group Type option. Each voice group has the following
settings that apply to all the voices in that group:
MIDI Channel
Voice Allocation Mode
Pitch Bend Amount
Glide Type
Glide Time
Glide Rate
Gate Type
Velocity/Trigger Output
Auxiliary Output
Auxiliary Output Scale
Each one of the settings listed above applies only to the voices in that voice group. That
means there can be different glide settings for each voice group, different voice allocation
modes, different MIDI channels, etc., or in the odd case, more than one group can have the
same MIDI receive channel! They are completely independent from each other.
To get a feel for how a voice group works, let’s hook up the MOTM-650 to some modules.
For the sake of this example, we’ll assume you want to control a single VCO. Set the
MOTM-650 as follows:
• Go to the Global Settings menu and change the Voice Group Type (VGrpType)
to 4 (single group, 4 voices per group).
• Press ESC to return to the top menu level, select the VoxGrp 1 Settings submenu,
and press ENTER. The first option shown is VG1 MIDI. If it’s not already set to the
same channel as your MIDI control, then set it now.
• Pressing INC should display VG1Alloc – set the option to Solo for now. This will
cause the MOTM-650 to allocate only the first voice in the group of 4.
• Connect a cable from the CV1 output to the 1V/OCT input of a VCO. Connect the
VCO’s output to a VCA’s audio input. Connect the MOTM-650’s GATE 1 output to
the VCA’s CV input. Finally, connect the VCA’s output to a monitoring setup (e.g.
amplifier or headphones).
Now press a key on the MIDI controller. If everything is set correctly, then several things
should happen:
• The MIDI LED will blink
• The V1 LED will turn on
• The played note will be heard
Try the pitch bend (set to 2 note -/+ bend range by default), a few more notes, etc…
Everything should respond like a normal monophonic synthesizer.

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Now, change VG1Alloc to Poly1. This will cause the MOTM-650 to allocate voices
polyphonically. Since the MOTM-650 is set to 4 voices, it will allocate from a pool of all 4
voices. Even if voices 2 through 4 aren’t connected to anything, play some notes. Every note
press will cause the next voice to be allocated, as you will see on the V1-V4 LEDs. With one
VCO connected, only 1 voice will be heard out of every 4 notes.
The MOTM-650 is currently set up for a single voice group. Go into the Global Settings
menu and change the Voice Group Type to 2/2 (two groups, 2 voices per group). Escape
out to the top-level menu, and notice that VoxGrp 2 Settings is now a new menu option!
As with VoxGrp 1, change VG2Alloc to Poly1 just like with Voice Group 1. Also set the
MIDI Channel to a different channel (preferably one higher than it’s currently set).
Now press notes on the controller keyboard. Notice now that only voices 1 and 2 are active –
this is sending MIDI data to Voice Group 1. Change the keyboard controller to the same
MIDI channel as Voice Group 2, and play. Voices are allocated out of voices 3 and 4. The
voice grouping operation allows completely different behaviors, turning the MOTM-650 into
a dual 2 voice MIDI/CV converter, or a quad single voice MIDI/CV converter. Very powerful
and flexible!
The MOTM-650 has one very unique function – voice groups can be assigned to the same
MIDI Channel. Change Voice Group 1’s channel to the same as Voice Group 2’s
channel. Play notes. Watch voice 1 & 3 turn on simultaneously, and 2 & 4 turn on
simultaneously.
Having both voice groups set to the same MIDI Channel is identical to sending
notes/controllers on two different channels – the single incoming note is being sent to both
voice groups.
One possible use for this is to have multiple VCOs on a single voice. Connect one VCO to
voice 1, and another to voice 3. Detune the second VCO to an octave below (or above), etc…
it’s a great way to get unique voices if a CV splitter isn’t available. Also consider that each
voice group can have different glide settings. Configuration of a modular system with this
voice group setup is only limited by the user’s imagination.
Now that the voice group concept has been covered, let’s explore all of the settings available
for each voice group. For each setting, a typical LCD display will be shown, then the
various options for that setting will be described in detail. Every voice group setting begins
with the letters VG, for Voice Group, and the number of the group selected – 1, 2, 3, or 4.
Here are the settings, in the order they appear as the INC button is pushed:
VG1 MID I
Chan=1
The MIDI Channel setting selects the voice group’s MIDI channel. Chan refers to the
channel number, of course, and can be set to any channel from 1 to 16. The voice group will
respond to MIDI CCs, pitch bend, notes, and all other voice group functions on this channel.
As mentioned earlier, more than one voice group can be set to the same MIDI channel.

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VG1Alloc
Solo
Voice Allocation Mode - What is “voice allocation”? In an ideal world, we’d always have
all the synth voices we need to sound the notes we want to play. Unfortunately, there are
usually fewer synth voices than notes on the keyboard, so there has to be a way to allocate
the many possible notes to the few available voices. In fact, there are many ways to
allocate voices to notes, some having surprisingly different musical results.
The MOTM-650 has 9 voice allocation modes that are assignable on a per group basis.
Each voice allocation mode has a specific use, and is described below. For the sake of
understanding how they differ, set the Voice Group Type to 4and pay close attention to
the voice gate LEDs (V1-V4) to visually grasp how the voices are allocated.
Solo
Solo mode will only sound one note at a time. Which note is selected depends on the
setting of the global Solo Note Priority option – either the Low Note, High Note, or
Last Note played. When a second note is played while the first one is still held, the CV
output will change, but the GATE output will stay high. If the Velocity/Trigger Output is
set to S-Trigger mode, then the VEL output won’t retrigger. Only one voice is used in Solo
mode – the first voice in the group. This the only allocation mode that doesn’t use all
available voices.
Solo Rot
Solo Rotate also sounds only one note. However, each new note is assigned to a new voice,
rotating through all the voices in the group, starting with the first voice. This mode is good
for playing short, percussive sounds with a long release, because new notes will not
immediately interrupt the release with a new attack like in Solo mode (unless many notes
are played quickly). All available voices are used in Solo Rotate mode.
Solo Uni
Solo Unison, like the other solo modes, only sounds one note. However, all available
voices are used to play this note. If the Voice Group Type is set to 1/1/1/1, this means only
one voice is available, so Solo Unison will work exactly like Solo mode. If the Voice
Group Type is set to 2/2 or 4, then more voices are available. Detuning the oscillators
that the CV outputs are connected to can create a very fat sound in Solo Unison mode.
Poly1
Poly 1 mode is polyphonic, meaning more than one note can be played at a time. Its
allocation algorithm is designed to preserve a note's release as long as possible. The last
note released is the last voice to be reallocated. For example: if A B C D are played in

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order, releasing the keys in reverse order (D C B A) will cause the next allocated voice to be
D. That is because it has been released the longest, so it has the best chance of having
completed the release cycle of its envelopes. If more notes are played than there are voices,
then only the first notes will sound, at least until one of those notes playing is released. At
that point, its voice will be reallocated to the next note in line. The GATE output will stay
high. If the Velocity/Trigger Output is set to S-Trigger, then the VEL output won’t
retrigger when the previously held note is sounded.
Poly1St
Poly 1 Steal works like the Poly 1 mode until all the voices are used and another note is
played. At that point, the new note will “steal” the voice of the first note played. If the
Velocity/Trigger Output is set to S-Trigger, then it will retrigger when the voice is
stolen. If the first note is still held when the new note is released, its voice will be restored,
however, the VEL output won’t retrigger if set to S-Trigger.
Poly2
Poly 2 is a polyphonic allocation algorithm which always allocates the first voice in its
voice group first, the second voice second, and so on. Poly 2 is useful for ensuring that
notes are assigned to voices in a predictable manner. This can be used with the Glide
feature to make a super cool polyphonic portamento sound. Poly 2, like Poly 1, does
nothing when more notes are played than there are voices.
Poly2 St
Poly 2 Steal works like the Poly 2 mode until all the voices are used and another note is
played. At that point, the new note will “steal” the voice of the first note played, just like
Poly 1 Steal mode.
Unison
Unison is yet another polyphonic mode. The idea behind Unison is to make the fattest
sound possible, by assigning multiple voices to each note. Unison mode works like Solo
Unison for the first note played, in that it allocates all of the voices to playing the note.
Then things start getting strange. If two or more notes are being played, the voices are
divided between the notes played. For instance, if the Voice Group Type is 4, then there
are 4 voices available. The first note played will use all 4 voices, the second note will steal
2 of those voices so that each note has 2 voices, the third note will steal one voice from the
first note and turn off one of the second note’s voices, the fourth note will play that turned
off note, and subsequent notes will be ignored until one of the first 4 notes are released. If
the Voice Group Type is 2/2, then there are 2 voices available, so the first note will play
with 2 voices, the second note with one, and subsequent notes will be ignored, just as they
are with Poly 1 and Poly 2.

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Unison St
Unison Steal works like Unison mode until all the voices are used and another note is
played. At that point, the new note will “steal” the voice of the first note played, just like
the Poly 1 Steal & Poly 2 Steal modes do.
VG1PBend
_2
The Pitch Bend Range setting controls the number of notes (half-steps) that the pitch will
change when a pitch bend wheel is at either end of its range (i.e. the pitch bend CC received
is at its maximum or minimum value). The range can be set from 0(off) to 24 (2 octaves).
When using MIDI pitch bend to control an AUX output, you may not want it to change the
pitch as well, in which case you should set the Pitch Bend Range to 0.
VG1Glide
_Off
The Glide Type setting selects between one of the MOTM-650’s two modes of Glide (or
portamento as it’s referred to by almost everyone except Moog & MOTM!), or having no
glide at all. Normally, when a voice is reallocated to a new note, the CV output changes
voltages nearly instantaneously. When glide is enabled, the voltage changes a Constant
Rate or Constant Time, depending on which Glide Type is selected. This allows the
pitch to “glide” from the old note to the new note.
When playing polyphonically, each individual voice within a voice group will glide
independently to the target note assigned to that voice. For example, with the Voice
Group Type set to 4, it’s possible for voice 1 to be sliding from middle C to high C, while
voice 2 is sliding from middle C to low C, and voices 3 and 4 are not gliding at all. CVs
continue to slide even after notes are released – glide works independently of the gates.
Glides always occur between the CVs of the source and target notes. This means that it’s
based on CV value, not on MIDI note. Glide will slide between the CV values for any
Tuning Table.
On powerup, all CVs are set to 0 volts, and will glide from that point to the first note
pressed.
The possible settings for Glide Type are as follows:
Off
As you’d expect, this option turns glide off. Glide can also be toggled on and off by sending
the standard portamento continuous controller message via MIDI.

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ConsTime
Constant Time glide will maintain the same time between two notes regardless of their
distance. The time can be set differently for each voice group.
ConsRate
Constant Rate glide allows a consistent rate of glide, meaning a shorter glide time for
notes that are closer together than those farther apart. This rate can be set differently for
each voice group.
VG1 Time
01.000 S
The Glide Time setting controls the time it takes a CV to glide from one note to another.
The Glide Time is adjustable in 1 millisecond increments from 1 ms to 65.535 seconds.
This menu only appears when the Glide Type is set to Constant Time.
VG1 Rate
_5
The Glide Rate setting controls rate and which a CV glides from one note to another. The
rate follows an exponential curve from 60.562 cents/second to 16898.837 cents/second with
128 steps. This menu only appears when the Glide Type is set to Constant Rate.
VG1 Gate
Normal
The Gate Type setting controls the behavior of the voltage present at the GATE outputs
associated with the current voice group.
Normal
The Normal Gate Type option will keep the GATE output at 0VDC until a Note On is
received, at which point the output will go to 12VDC. It will stay there as long as the note
is held. When a Note Off is received, the output will return to 0VDC. This is how gates
work on almost all non-Moog synthesizers (though the full scale voltage may vary).
STrigger
The Shorting Trigger Gate Type option will keep the GATE output at 12VDC until a
Note On is received, at which point the output will go to 0VDC until a Note Off is received,
when the output will return to 12VDC. This is how gates work on Moogs. When the S-

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Trigger setting is selected, the voice gate LED (V1-V4) associated with the voices in the
voice group will turn on, because the LEDs are driven directly by the GATE outputs.
VG1 V/T_
Velocity
The Velocity/Trigger Output setting controls how the VEL outputs work.
Velocity
The Velocity option makes the VEL output a CV that corresponds to the velocity value
received with the current Note On. A velocity of 127 will set the voltage to the maximum as
determined by the global Velocity Scale option. Velocities of 0 are ignored, as these
messages are interpreted as a Note Off command.
Trigger
The Trigger option will output a trigger pulse of 12VDC whenever a new note is played.
The pulse width is controlled by the global Trigger Pulse Width setting. This is useful for
retriggering envelopes in the solo Voice Allocation Modes, as the GATE output will
remain high if notes are played legato. Remember though, that in some cases a new note
will not cause a trigger pulse, as described in the Voice Allocation Mode section.
VG1 Aux1
CC1 ModW
The Auxiliary Output setting controls how the AUX outputs work. AUX 1 is part of Voice
1, AUX 2 is part of Voice 2, etcetera, so when the Voice Group Type changes, the Auxiliary
Output setting may change Voice Groups with the other voice settings. If the AUX out is
controlled by a MIDI parameter, then it receives messages on the same channel as its Voice
Group. The control options are as follows:
CC0-CC31
Continuous Controller messages 0through 31 can be selected as sources for the AUX
outputs, with 128 possible voltage levels corresponding to the controller’s current value.
Note that some CCs, such as CC1 ModW, include an abbreviated description of the
controller commonly associated with that controller number - in this case, the Modulation
Wheel.
PitchBnd
The Pitch Bend option will output a CV that is proportional to the value of the Pitch Bend
CC. The most significant 10 bits are used to scale the voltage set by the Auxiliary Scale
setting, for 1024 possible voltage levels.