Full Bucket
Vocoder FBVC
Version 1.0
© 2019 by Björn Arlt
http://www.fullbucket.de/music
VST is a trademark of Steinberg Media Technologies GmbH
Windows is a registered trademark of Microsoft Corporation
The Audio Units logo is a trademark of Apple Computer, Inc.
Full Bucket Vocoder FBVC Manual Page 2
Table of Contents
Introduction....................................................3
The Voice of the Past........................................3
The Voice of Today...........................................3
Acknowledgments............................................4
Basic Operation...............................................5
The Microphone Section (MIC)...........................5
The Tone Generator Section..............................5
The External Section (EXT)...............................6
The VU Meter..................................................6
Ensemble and Output Section............................6
Input Mode.....................................................6
Vocoder Mode.................................................6
Switching the “Keyboard” On/Off.......................7
Advanced Operation.........................................7
Tweaking the Vocoder Bands.............................7
Bias, Limit, and Speed – Imperative Imperfection 8
Tone Generator Envelope..................................8
Ensemble.......................................................8
Control Operation............................................8
The Sound Manager.........................................8
MIDI Learn And The Configuration File “fbvc.ini”. .9
Options Menu..................................................9
Parameters...................................................10
Frequently Asked Questions.............................11
Full Bucket Vocoder FBVC Manual Page 3
Introduction
The Full Bucket Vocoder FBVC is a software plug-in for Microsoft Windows (VST) and
Apple macOS (VST/AU) simulating the classic KORG® VC-10 Vocoder from 1978. It is
written in native C++ code for high performance and low CPU consumption. The main
features are:
● 20 band full stereo vocoder
● 64 voice polyphonic built-in Tone Generator section
● Accent Bending and Vibrato effects
● Optional WAV file playback
● Fully tweakable Analysis/Synthesis section
● Tweakable Ensemble effect
● Double precision audio processing
● All parameters can be controlled by MIDI controllers
● Plug-in supports Windows and macOS (32 bit and 64 bit)
The Voice of the Past
Once upon a time I promised myself not to create a simulation of an existing piece of
hardware that I do not own by myself. Well, as you can see, I broke my promise
again: I never owned a VC-10 nor is it very likely that I ever will. Hey, sounds like the
introduction to my Nabla and Stigma synthesizers! ;-)
In 1978, KORG presented the VC-10 Vocoder. This neat little instrument was
packaged in a MS-10 housing plus goose-neck microphone and keyboard that allowed
for instant vocoding experience without attaching any other gear. The integrated Tone
Generator was “fully polyphonic” (meaning that each key produced an individual
Sawtooth wave), could be mixed with an additional White Noise source, and served as
the Carrier signal, while the microphone input provided the Modulator signal. Of
course it was possible to replace both Carrier and Modulator with external signal
sources.
The VC-10 also offered some more cool effects like Accent Bend (where the level of
the Modulator signal “bends” the pitch of the Tone Generator) and Vibrato for the Tone
Generator, as well as Ensemble (known from the PS-3100/3200 and the Delta). But it
also had some drawbacks like a missing voiced/unvoiced detector and even potential
design flaws - for example the highest four filters of the vocoder section were only
fed with the noise signal). But despite of these disadvantages the VC-10 was a
fantastic instrument and well worth being recreated in software.
The Voice of Today
When creating the FBVC I took some liberty in that I added/changed the following
features which cannot be found in the original VC-10:
● Full stereo operation
● 64 voice polyphonic Tone Generator supporting all MIDI note values (not only
the 32 keys plus one octave)
● Velocity control for the Tone Generator
● Modulator signal can be replaced by mono/stereo WAV file playback
Full Bucket Vocoder FBVC Manual Page 4
● Mode can be switched from “Standard” to the “Full Band” mode (where the
signal of the Tone Generator is fed into all 20 bands)
● Tweak section:
• Adjustable frequencies of all Analysis and Synthesis bands
• Adjustable levels of all Synthesis bands
• All Analysis and Synthesis bands can be switched to fixed levels
• Bias and Limit for filter output VCAs
• Attack and Release for Tone Generators
• Adjustable LFO rates for Ensemble effect
● Not to forget: 64 presets and MIDI CC support!
The architecture of the FBVC is visualized by the following block diagram on the front
panel.
Architecture of the FBVC
So how does it work? The microphone input signal (well, any signal you feed into the
first two inputs of the FBVC…) is used as the Modulator signal, i.e. it is analyzed by 20
bandpass filters and their responses are converted into 20 control signals. The Tone
Generator signal mixed with the Noise and the external signal (any signal you feed
into inputs 3 and 4 of the FBVC) serves as the Carrier signal: It is filtered by another
bunch of 20 bandpass filters and their level is controlled in real-time by the control
signals of the Modulator. These filtered carrier signals, summed-up and optionally
send to the Ensemble effect, provide the output signal. Magic.
Acknowledgments
And at this point I would also like to say Thank you! to all the people who share their
information about the VC-10 via the Internet, especially:
• Eric G at http://hem.bredband.net/elmuced/ericg.htm and
• Ben Ward for his excellent supporting material at
http://www.korganalogue.net/.
And another THANK YOU! to the KVR Audio community and to the KORG engineers.
No, I am not affiliated with KORG in what relation ever except that I always find
myself entangled with their instruments.
Full Bucket Vocoder FBVC Manual Page 5
Basic Operation
Although the panel of the VC-10 (and thus the panel of the FBVC) is laid out neatly, it
is at the same time a bit cluttered. Let’s get the pieces together!
The Microphone Section (MIC)
The Microphone section stands as a synonym for anything concerning the Modulator
signal. It has only one control, namely the “MIC LEVEL” knob that controls the input
volume.
Being a software plug-in, the FBVC of course does not have a real microphone. In fact
the latter refers to the first two inputs, “MIC Left” and “MIC Right”.
The Tone Generator Section
The Tone Generator produces the internal signals for the Carrier. It can be mixed with
a White Noise signal via the “IN BALANCE” knob and shifted one octave up using the
“OCTAVE” switch. Fine tuning is done by the “TUNE” knob, and three (!) independent
LFOs provide a Vibrato effect with adjustable “SPEED” and “DEPTH”.
“ACCENT BEND” bends the pitch of the Tone Generator with respect to the level of the
analyzed Modulator signal. This is a pretty spooky effect – according to the original
Owner’s Manual of the VC-10 it “adds a slight pitch wavering effect so that the sound
produced is more like a real human voice”. Try it yourself.
“PITCH BEND” controls the amount of Pitch Bending of the Tone Generator (± 12
notes). Finally, the “VELOCITY” knob controls the amount of velocity applied to the
volume of a played key. Note that the original VC-10 was not sensitive to velocity.
Full Bucket Vocoder FBVC Manual Page 6
The External Section (EXT)
In parallel to the Tone Generator, you can use an external signal plugged into inputs 3
(“EXT Left”) and 4 (“EXT Right”) of the FBVC plug-in as a Carrier signal. The volume
of this signal is controlled by the “EXT LEVEL” knob.
The VU Meter
Like the VC-10, the FBVC offers a VU meter to check the levels of the Carrier or
Modulator signals. Note that the VU meter is an analog device – the readout values
may differ a little bit from the exact level values.
Ensemble and Output Section
The Ensemble effect can be activated using the “ENSEMBLE” switch, and the “OUT
BALANCE” knob controls the mix between Vocoder and Microphone (input) signal sent
to the output. The total output volume is set by the “FINAL VOLUME” knob.
Input Mode
Typically, the Modulator signal is derived from the Microphone input (MIC) i.e.
whatever is plugged into the inputs “MIC Left” and “MIC Right” of the FBVC. However,
the FBVC allows to load a mono or stereo WAV file which can be used as the Modulator
signal instead. To select the input and/or a WAV file just click on the box right to the
“INPUT” label under the block diagram.
Example menu entries for the Input mode.
When you select a WAV file, its playback will be triggered by the keyboard. In
“Legato” mode, playback starts once for the first key you press and will restart only if
all keys have been released. If “Legato” mode is deselected, playback restarts with
each key you press.
Note that you can set the default path for your WAV files using the Options Menu.
Vocoder Mode
As stated already in the introductory section, the VC-10 had a minor design flaw (well,
I am not sure if it really was a flaw!): The highest four bands of the Synthesis section
are only fed with the Noise signal but not with the Tone Generator of external signal.
Thus, only the first sixteen bands could really be used for the Tone Generator.
Full Bucket Vocoder FBVC Manual Page 7
The FBVC can fix this flaw by clicking the box right beneath the Input mode box. Here
you can switch the Vocoder mode from “VC-10 Standard” to “VC-10 Full Bands”.
Switching the “Keyboard” On/Off
The “KBD” switch right to the Vocoder Mode box (not to be found on the real VC-10)
can be used to switch the internal “keyboard” of. This means that incoming MIDI
notes do not generate a sound. WAV playback however will still be triggered. The
handiness of this switch will be clear once you really need it! ;-)
Advanced Operation
Now we are getting to the advanced operation modes of the FBVC – the tweaks! Click
on the little at the lower right of the front panel and get ready.
Tweaking the Vocoder Bands
The trim pots in first row “ANALYSIS” can be used to set the center frequency of the
20 analysis bandpass filters.
Note: Each bandpass of the FBVC consists of a series of two 2-pole bandpass filters with
identical Q. The center frequency of the second filter is 0.829 times lower than the center
frequency of the first filter. The frequency displayed in the FBVC is always the frequency of
the first filter.
The trim pots in the second row “FILTER” control the center frequencies of the
Synthesis filters while the trim pots of the third row “LEVEL” set their respective
levels.
The switches of the fourth row determine if the aplitude of a Synthesis filter will be
modulated (via a VCA) by the respective output of the Analysis filter or if it will remain
fixed. This feature allows to turn the FBVC into a fixed filter bank!
The “TOOLS” buttons opens a menu with some little helpers to set the various vocoder
band parameters (including reset to default).
Full Bucket Vocoder FBVC Manual Page 8
Bias, Limit, and Speed – Imperative Imperfection
Compared to the original VC-10 the FBVC sounds rather “clean” and “precise” because
crucial parts of the VC-10 were analog circuitry having a rather limited working range.
This was especially true for the 20 VCAs which controlled the filter band’s amplitude.
The level at which the VCAs started to operate could be set via a trimmer potentiometer at the back side of the VC-10. Normally this was done only once by the
manufacturer but due to component aging etc. it would have been necessary to
readjust this Bias. On the FBVC this trimmer is realized by the “BIAS” control on the
tweak panel. Note that at a Bias level higher than 0 the FBVC produces a sound even
if no Modulator signal is applied.
Another “problem” with the VCAs of the VC-10 was that at a certain level of the
control input voltage the amplification of the respective VCA did not increase any more
– the VCA control was “limited” to a maximum value. This behavior can be simulated
with the “LIMIT” control: The higher the value of “LIMIT”, the more extreme is the
simulated limiting effect.
Finally you can adjust the responsiveness of the VCAs i.e. the “speed” at which they
react to changes of the control voltages. The respective control is called “SPEED”.
If you play with the “BIAS”, “LIMIT” and “SPEED” controls you will soon find a setting
that closely simulates the “imperfect” sound of the real VC-10. For sound comparison
I recommend the nice track “Guten Abend, Leute” by Dorothea Raukes (Deutsche
Wertarbeit).
Tone Generator Envelope
The Tone Generator of the VC-10 provided just an organ-like envelope of the signal
amplitudes – even simple string machines could do more! That’s why I added an
“ATTACK” and “RELEASE” control to the FBVC. Note that the WAV playback is affected
by this envelope too.
Ensemble
The original Ensemble effect earned a lot of criticism because its speed was fixed and
to fast by default. Being controlled by two LFOs (a “slow” and a “fast” one) I decided
to make their rates being set by dedicated controls (in fact four of them because the
FBVC is stereo).
Control Operation
The Sound Manager
To select one of the 64 patches just click on the program number or the previous/next
arrow buttons, and edit its name by clicking in the text field.
Full Bucket Vocoder FBVC Manual Page 9
MIDI Learn And The Configuration File “fbvc.ini”
Every parameter of the FBVC can be controlled by one MIDI controller. If you want to
change the assignment of MIDI controller (CC; MIDI Control Change) to FBVC
parameter the MIDI Learn function comes in quite handy: Just click the MIDI button
on the Sound Manager panel (button turns yellow) and wiggle both the MIDI controller
and the parameter you want to assign (you can abort LEARN by clicking the button
again). If you want to unlearn the assignment, right-click the MIDI Learn button (the
label now reads “UNLEARN”). Now wiggle the MIDI controller or the parameter that
you want to unlearn. To save the controller assignments use “Save Configuration” in
the Options menu (see next section); they are stored in the fbvc.ini configuration
file. The exact location of this file depends on your operating system and will be
displayed when you click on “Reload” or “Save Configuration”.
Options Menu
When clicking on the disk symbol of the File button, a context menu opens with the
following options:
Copy Program Copy current program to internal clipboard
Paste Program Paste internal clipboard to current program
Load Program Load a program file containing a patch to the FBVC's
current program
Save Program Save the FBVC's current program to a program file
Load Bank Load a bank file containing 64 patches into the FBVC
Save Bank Save the FBVC's 64 patches to a bank file
Init Program Initialize the current program
Default Path for
WAV Files
Sets the default path for WAV files when using the WAV
playback option (see section Input Mode)
MIDI Thru Set globally if MIDI data sent to the FBVC should be sent
through to its MIDI output (stored in configuration file)
Ignore Program
Change
Set globally if MIDI Program Change data sent to the
FBVC should be ignored (stored in configuration file)
Reload Configuration Reload the FBVC's configuration file
Save Configuration Save the FBVC's configuration file
Check Online for
Update
When connected to the Internet, this function will check if
a newer version of the FBVC is available at fullbucket.de
Visit fullbucket.de Open fullbucket.de in your standard browser
Full Bucket Vocoder FBVC Manual Page 10
Parameters
parameter ID description
Vocoder Mode 0 “VC-10 Standard” or “VC-10 Full Bands”
KBD Mode 1 Keyboard (Tone Generator) off/on
Input Mode 2 Selects signal input or WAV sample playback
Sample Legato 3 Legato WAV sample playback
Final Volume 4 Final output volume
Out Balance 5 Mix between input signal and Vocoder signal
Tune 6 Master tune of the Tone Generator
Velocity 7 Amount of velocity applied to the Tone Generator
Octave 8 Shifts the Tone Generator’s pitch one octave up
In Balance 9 Mix between Tone Generator and external input
Ext Level 10 Level of external signal input
Mic Level 11 Level of signal (Microphone) input
Accent Bend 12 Depth of Accent Bend applied to Tone Generator
Pitch Bend 13 Depth of Pitch Bend applied to Tone Generator
Vibrator Speed 14 Speed of the Vibrato effect
Vibrato Depth 15 Depth of the Vibrato effect
Ensemble 16 Ensemble effect off/on
Meter Mode 17 Select Carrier or Modulator signal for VU meter
Attack 18 Attack of Tone Generator envelope
Release 19 Release of Tone Generator envelope
Ensemble (L) Rate 1 20 Rate of first LFO of left Ensemble unit
Ensemble (L) Rate 2 21 Rate of second LFO of left Ensemble unit
Ensemble (R) Rate 1 22 Rate of first LFO of right Ensemble unit
Ensemble (R) Rate 2 23 Rate of second LFO of right Ensemble unit
Analysis Frequency 24–43 Center frequencies of the analysis filters
Synthesis Frequency 44–63 Center frequencies of the synthesis filters
Synthesis Frequency 64–83 Levels of the synthesis filters
Synthesis Fixed 84–103 Sets synthesis filter VCAs to modulated or fixed
Bias 104 Bias of the filter VCAs control
Limit 105 Limit (peak) of the filter VCAs control
Speed 106 Speed (responsiveness) of the filter VCAs control
Full Bucket Vocoder FBVC Manual Page 11
Frequently Asked Questions
How do I install the FBVC (Windows 32 bit version)?
Just copy the files fbvc.dll from the ZIP archive you have downloaded to your
system's or favorite DAW's VST plug-in folder. Your DAW should automatically register
the FBVC VST plug-in the next time you start it.
How do I install the FBVC (Windows 64 bit version)?
Just copy the file fbvc64.dll from the ZIP archive you have downloaded to your
system's or favorite DAW's VST plug-in folder. Your DAW should automatically register
the FBVC VST plug-in the next time you start it.
Note: You may have to remove any existing (32 bit) fbvc.dll from your VST plug-in
folder or else your DAW may screw the versions up...
How do I install the FBVC (Mac VST/AU universal 32/64 bit)?
Locate the downloaded PKG package file fbvc_1_0_0_mac.pkg in Finder (!) and do a
right- or control-click on it. In the context menu, click on “Open”. You will be asked if
you really want to install the package because it comes from an “unidentified
developer” (me ). Click “OK” and follow the installation instructions.
What is the plug-in ID of the FBVC?
The ID is f b v c .
How do I know if a new version of the FBVC is available?
When connected to the Internet, open the File menu (see section Options Menu) by
clicking the disk icon and select the entry “Check Online for Updates”. If a new version
of the FBVC is available on fullbucket.de the respective information will be shown in a
message box.
The stock preset “XYZ (WAV play)” does not produce any
sound!?
Copy the three WAV files that
• (Windows) come with the ZIP archive
• (Mac) are automatically installed under /Users/Shared/FullBucketMusic/
into your default WAV folder. You can set this folder using the Options Menu.
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