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.
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