Full Bucket
Brigade Delay
Analog Delay Simulation
Version 1.2
© 2017-2019 by Björn Arlt @ Full Bucket Music
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 Brigade Delay Manual Page 2
Introduction
The Full Bucket Brigade Delay is an effect plug-in for Microsoft Windows (VST) and
Apple macOS (VST/AU) simulating the functionality and sound of classic analog
delays. It is written in native C++ code for high performance and extremely low CPU
consumption. The main features are:
● Authentic simulation of a bucket brigade device (BBD) delay line
● No “crackling” or “dropouts” when changing the delay time
● LFO modulation for Flanger, Chorus, or other modulation effects
● Freeze mode
● Stereo!
● Quality control to send your hi-fi signals to hell
● Double precision audio processing
● Plug-in supports Windows and macOS (32 bit and 64 bit)
Gosh, Why Another Delay Plug-In?
The Full Bucket Brigade Delay is an offspring of the tiny delay within my Nabla
synthesizer. Just for fun I separated it into its own C++ project, added a few things
like the LFO and the Quality control, always trying to achieve the functionality and
sound of those old BBD units that I love so much. Now I sat here with a new plug-in.
And decided to share it.
What Is a Bucket Brigade Device?
In a bucket brigade device, the incoming audio signal is sampled at a specific
frequency, the clock rate (typically some kHz), and fed into the first of a line of
subsequent bins or “buckets” (see figure below). At the same time, the original
content of the first bucket is put into the second bucket while the original content of
the second bucket is put in to the third bucket while… you got the story. The content
of the last bucket is sent to the output of the device. It may additionally be attenuated
and sent back to the input ‒ this is called Regeneration or Feedback. Since the whole
process is repeated with every clock cycle, it takes some time until the original input
sample appears at the output of the device; the signal is delayed.
Sketch of a bucket brigade device (BBD) delay line with feedback.
+
clock
Full Bucket Brigade Delay Manual Page 3
Now it is some kind of obvious (*cough, cough*) that the clock rate determines how
fast the samples are moving through the BBD and thus how long the delay time is.
This has three immediate consequences:
• Higher clock rates result in shorter delay times and lower clock rates in longer
delay times.
• No matter how high the clock rate, there is always some delay between input
and output of the BBD ‒ because the samples always have to travel through all
the buckets.
• If the clock rate is varied, the samples that are already “in” the BBD will appear
at a different rate at the output than they had been sampled at the input. Thus
their “frequency” will change.
(Feel free to check the Full Bucket Brigade Delay if it is really working this way!)
Wait a minute: Sampling is used here? Why is a BBD delay line then called “analog”?
Because the “samples” are not digitized but handled “as is”: They are “measurements” of a continuous signal, discrete in time but still continuous with respect to
their values (well, almost…), and as such they travel through the BBD.
Of course this will have other side effects: Since buckets of a BBD are not perfect
analog memory elements, the signal quality will degrade with the length of the BBD
and the clock rate. Typically, the frequency range of the delayed signal is smaller than
the one of the original signal; even more, the delayed signal may be slightly distorted.
In the past this was considered to be a major problem, today we call it “analog” and
love it for the resulting “warm” sound!
User Interface
The layout of the Full Bucket Brigade Delay's user interface is straight forward: In the
“DELAY” section you can select the delay time range (1‒8ms, 4‒31ms, 16‒125ms,
31‒500ms), set the delay time itself, and adjust the feedback level. Note that
changing the delay time will change the frequency of whatever signal is already “in”
the delay line.
Click the yellow triangle to select one of the ten presets
Full Bucket Brigade Delay Manual Page 4
The “LFO” section controls the speed (up to 25Hz) and the depth of the low frequency
oscillator modulating the delay time. Here lies the origin of all those nice effects
named Flanger, Chorus, LSD Trip Echo, Psychotic Slapback etc.
The mix between original and effect is set in the “OUTPUT” section along with the
“quality” of the delayed signal: The lower the value of the Quality parameter, the
higher the analogishness of the effect.
Have fun with the Freeze mode: Click on the “FREEZE” button, and whatever is
currently in the delay line will be looped forever until you click the button again. Note
that in “Freeze” mode the input is “locked” i.e. the input signal will not be added to
the delay line.
Finally, you can select one of the ten presets by clicking on the yellow triangle at the
top left corner of the effect screen. These presets give you some examples of what
you can do with the Full Bucket Brigade Delay.
Tip: If you want to know what I remember best of those old BBDs then turn Feedback
to maximum (100%) and Quality to some low value (~30%) and twiddle the Time
parameter. And better reduce the volume of your amp.
MIDI Control Change Messages
All parameters of the Full Bucket Brigade Delay can be controlled by MIDI controllers,
or more precise: Each MIDI controller can control one of Full Bucket Brigade Delay’s
parameters. The mapping is defined in the fbdelay.ini configuration file like this:
[MIDI Control]
CC4 = 10 # Freeze
CC70 = 1 # Delay Time
CC71 = 2 # Feedback
...
The syntax is straight forward:
CC<controllernumber> = <parameterID>
Given the above example, controller 4 directly controls the Freeze mode, controller 70
the Delay Time etc. As you can see, comments are introduced by the Pound sign (#);
they are here just for description purposes and completely optional.
The fbdelay.ini file is located in the same directory as the Full Bucket Brigade Delay
VST DLL (fbdelay.dll or fbdelay64.dll) or Mac VST/AU (FBDelay.component or
FBDelay.vst) itself; you can edit this file in a standard text editor. Next time your
DAW host program starts, the Full Bucket Brigade Delay will load the changes.
Full Bucket Brigade Delay Manual Page 5
MIDI Learn
The easiest way to assign MIDI controllers to Full Bucket Brigade Delay parameters is
to use the MIDI Learn function. To activate MIDI Learn, click on the “LEARN” button
and wiggle both the MIDI controller and the Full Bucket Brigade Delay’s parameter
that you want to link. If you want to unlearn the assignment, right-click the “LEARN”
button (the label now reads “UNLEARN”) and activate it. Now wiggle the MIDI
controller or the parameter that you want to unlearn.
Parameters
parameter ID description
Range 0 Coarse range of the delay time:
1‒8ms, 4‒31ms, 16‒125ms, or 31‒500ms
Time 1 Delay time with respect to the delay time range
Feedback 2 Amount of feedback
Speed 3 LFO speed (0 to 25 Hz)
Depth 4 Depth of delay time modulation by LFO
Mix 5 Mix between original and effect signal
Quality 6 Quality of the simulated BBD delay line
Freeze 10 “Freeze” mode on/off
Full Bucket Brigade Delay Manual Page 6
Frequently Asked Questions
How do I install the Full Bucket Brigade Delay (Windows 32 bit
version)?
Just copy the file fbdelay.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 Full Bucket Brigade Delay VST plug-in the next time you start it.
How do I install the Full Bucket Brigade Delay (Windows 64 bit
version)?
Just copy the file fbdelay64.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 Full Bucket Brigade Delay VST plug-in the next time you start it.
Note: You may have to remove any existing (32 bit) fbdelay.dll from your VST
plug-in folder or else your DAW may screw the versions up...
How do I install the Full Bucket Brigade Delay (Mac VST/AU
universal 32/64 bit)?
Locate the downloaded PKG package file fbdelay_1_2_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 J). Click “OK” and follow the installation instructions.
What is the plug-in ID of the Full Bucket Brigade Delay?
The ID is f b b d .
No Sync-to-Host Tempo Possible? This Sucks!
Indeed. Like the original units.
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