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Update: 2022-09-09

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FDN64Reverb

FDN64Reverb is a reverb equipped with a feedback delay network (FDN). However, the size of feedback matrix is 64.

The package includes following builds:

Linux build is built on Ubuntu 20.04. If you are using distribution other than Ubuntu 20.04, plugin will not likely to run. In this case, please take a look at build instruction.

Contact

Feel free to contact me on GitHub repository or ryukau@gmail.com.

You can fund the development through paypal.me/ryukau. Current goal is to purchase M1 mac for better macOS support. 💸💻

Installation

Plugin

Place *.vst3 directory to:

DAW may provides additional VST3 directory. For more information, please refer to the manual of the DAW.

Presets

Extract preset zip, then place preset directory to the OS specific path:

Preset directory name must be the same as the plugin. Make Uhhyou directory if it does not exist.

Windows Specific

If DAW doesn’t recognize the plugin, try installing C++ redistributable (vc_redist.x64.exe). Installer can be found in the link below.

Linux Specific

On Ubuntu 18.0.4, those packages are required.

sudo apt install libxcb-cursor0  libxkbcommon-x11-0

If DAW doesn’t recognize the plugin, take a look at Package Requirements section of the link below and make sure all the VST3 related package is installed.

REAPER on Linux may not recognize the plugin. A workaround is to delete a file ~/.config/REAPER/reaper-vstplugins64.ini and restart REAPER.

macOS Specific

When trying to run plugin first time, following message may appear on macOS.

<PluginName>.vst3 is damaged and can't be opened. You should move it to
the Trash"

In this case, open terminal and try running following command to unzipped .vst3 directory.

xattr -rc /path/to/PluginName.vst3

Plugin may be considered as unsigned/un-notarized application. In this case, try following the steps below.

  1. Open terminal and run sudo spctl --master-disable.
  2. Go to System Preferences → Security and Privacy → General → Allow apps downloaded from, then select “Anywhere”.

Beware that steps above degrades security of your system. To revert the settings, follow the steps below.

  1. Go to System Preferences → Security and Privacy → General → Allow apps downloaded from, then select option to “App Store and identified developers”.
  2. Open terminal and run sudo spctl --master-enable.

Reference

GUI Style Configuration

At first time, create color config file to:

style.json will be loaded for each time a plugin window opens.

Several color themes are available on the link below.

Below is a example of style.json.

{
  "fontFamily": "Tinos",
  "fontBold": true,
  "fontItalic": true,
  "foreground": "#000000",
  "foregroundButtonOn": "#000000",
  "foregroundInactive": "#8a8a8a",
  "background": "#ffffff",
  "boxBackground": "#ffffff",
  "border": "#000000",
  "borderCheckbox": "#000000",
  "borderLabel": "#000000",
  "unfocused": "#dddddd",
  "highlightMain": "#0ba4f1",
  "highlightAccent": "#13c136",
  "highlightButton": "#fcc04f",
  "highlightWarning": "#fc8080",
  "overlay": "#00000088",
  "overlayHighlight": "#00ff0033"
}

Font Options

Following is a list of font options.

To use custom font, place *.ttf file into custom font path: *.vst3/Contents/Resources/Fonts.

Notice: If the combination of fontFamily, fontBold, fontItalic is not exists in custom font path, default font of VSTGUI is used.

If fontFamily is set to empty string "", then "Tinos" is used as fallback. If the length is greater than 1 and the font family name doesn’t exists, default font of VSTGUI is used.

Styles other than bold, italic or bold-italic are not supported by VSTGUI. For example, “Thin”, “Light”, “Medium”, and “Black” weights cannot be used.

Color Options

Hex color codes are used.

First letter # is conventional. Plugins ignore the first letter of color code, thus ?102938, \n11335577 are valid.

Do not use characters outside of 0-9a-f for color value.

Following is a list of color options. If an option is missing, default color will be used.

Controls

Right Click on the controls pops up a context menu provided by DAW.

Knob and slider can do:

Control with many blue vertical bars (BarBox) have some keyboard shortcuts. LFO Wave on Main tab and Gain, Width, Pitch, Phase on Wavetable tab are using BarBox. Shortcuts are enabled after left clicking BarBox and mouse cursor is on the inside of BarBox. Cheat sheet is available on Infomation tab.

Input Control
Left Drag Change Value
Shift + Left Drag Change Value (Snapped)
Ctrl + Left Drag Reset to Default
Ctrl + Shift + Left Drag Change Value (Skip Between Frames)
Right Drag Draw Line
Shift + Right Drag Edit One Bar
Ctrl + Right Drag Reset to Default
Ctrl + Shift + Right Drag Toggle Lock
a Alternate Sign
d Reset Everything to Default
D Toggle Min/Mid/Max
e Emphasize Low
E Emphasize High
f Low-pass Filter
F High-pass Filter
i Invert Value (Preserve minimum)
I Invert Value (Minimum to 0)
l Toggle Lock under Mouse Cursor
L Toggle Lock for All
n Normalize (Preserve minimum)
N Normalize (Minimum to 0)
p Permute
r Randomize
R Sparse Randomize
s Sort Descending Order
S Sort Ascending Order
t Subtle Randomize (Random walk)
T Subtle Randomize (Converge to 0)
z Undo
Z Redo
, (Comma) Rotate Back
. (Period) Rotate Forward
1 Decrease
2-9 Decrease 2n-9n

Snapping is not available for all BarBox. If you’d like to have snapping for certain BarBox, feel free to open issue to GitHub repository.

Edit One Bar with Shift + Right Drag holds a bar under the cursor when mouse right button is pressed. Then only changes that one bar while holding down mouse right button.

Toggle Lock with Ctrl + Shift + Right Drag behaves as line edit. When right mouse button (RMB) is pressed, it holds the opposite state of the bar below mouse cursor, then use the state for the rest of bars. For example, if RMB is pressed on a locked bar, dragging unlocks bars while holding down RMB.

Some BarBox has scroll bar to zoom in. Scroll bar has handles on left end and right end. To control zoom, use Left Drag on one of the handle. Scroll bar also has following controls:

Caution

Setting Feedback to 1 and Highpass Cutoff to 0 might adds massive direct current depending on input signal.

Block Diagram

If the image is small, use Ctrl + Mouse Wheel or “View Image” on right click menu to scale.

Diagram only shows overview. It’s not exact implementation.

Parameters

Delay Time [s]

Delay times in seconds. Below is the equation to calculate the total of delay time.

delayTime = (Time Multi.) * (Delay Time) + (Time LFO Amount) * random().

Note that maximum delay time do not exceed 1 second. This means that if both Delay Time and Time LFO Amount are set to 1, then LFO stop working.

Time LFO Amount [s]

Amounts of LFO modulation to delay times.

When Interp. Rate exceeds 1.0, LFO modulations start adding noticeable noise. To get smooth output, recommend to set Interp. Rate under 0.25.

Lowpass Cutoff [Hz]

Cutoff frequencies of lowpass filters that are applied to delay outputs.

Highpass Cutoff [Hz]

Cutoff frequencies of highpass filters that are applied to delay outputs.

Note that setting Feedback to 1 and Highpass Cutoff to 0 might adds massive direct current depending on input signal.

Delay

Time Multi.

A multiplier to Delay Time. Useful to change all the delay time at once.

Feedback

Feedback amount of FDN. In other words, Feedback is a scalar that multiplies feedback matrix.

When Feedback is close to 1.0, it lengthen the reverb time. When set to exactly 1.0, the reverb stop to decay. In this case, Gate can be used to shut down the reverb.

Interp. Rate

Rate limiting value of delay time interpolation. For example, when Interp. Rate is set to 0.1, changing delay time from 0 to 1 samples requires 10 samples of interpolation time.

Gate [dB]

Threshold of gate.

When input amplitude is less than the value of Gate for a while, the gate modulates Stereo Cross to make output amplitude to 0.

Gate is intended to use with rotation. Release time is approximately 5 ms.

Matrix

Type of feedback matrix. Note that changing this parameter may cause pop nosie.

Abbreviation Full Name Additional Infomation Quality
Ortho. Orthogonal Good
S. Ortho. Special orthogonal Good
Circ. Ortho. Circulant OK
Circ. 4 Circulant 4 non-zero elements per row SFX
Circ. 8 Circulant 8 non-zero elements per row SFX
Circ. 16 Circulant 16 non-zero elements per row SFX
Circ. 32 Circulant 32 non-zero elements per row SFX
Upper Tri. + Upper triangular Range of randomization is [0, 1] Bad
Upper Tri. - Upper triangular Range of randomization is [-1, 0] Bad
Lower Tri. + Lower triangular Range of randomization is [0, 1] Bad
Lower Tri. - Lower triangular Range of randomization is [-1, 0] Bad
Schroeder + Schroeder reverb Range of randomization is [0, 1] Bad
Schroeder - Schroeder reverb Range of randomization is [-1, 0] Bad
Absorbent + Absorbent allpass Range of randomization is [0, 1] OK
Absorbent - Absorbent allpass Range of randomization is [-1, 0] OK
Hadamard Hadamard No randomization Good
Conference Conference No randomization Good

Quality is rough indication. Bad means it frequently adds metallic tones to output. Good means almost no metallic tone. OK is in between good and bad. SFX means they sound strange as a reverb. Bad matrices can be used to add more effects with rotation.

Seed

Seed value for randomization of feedback matrix. Note that changing this parameter may cause pop nosie.

Change Matrix

A button to randomize feedback matrix. Pressing Change Matrix also changes the value of Seed. Note that changing this parameter may cause pop nosie.

Mix

Dry [dB]

A gain applied to input signal which bypasses FDN.

Wet [dB]

FDN output gain.

Stereo Cross

Stereo crossing feedback amount between left and right FDNs. Setting Stereo Cross to 1.0 stops input to prevent blow up.

Rotation

Speed [Hz]

Rotation speed of FDN input gains.

Offset

Initial phase of the waveform to rotate input gains.

Offset can be used to change the sound when Speed is 0, but Skew is greater than 0. Feedback matrix affects the character of output.

Skew

Changes the waveform used to rotate input gains. Note that when Skew is set to 0, Speed and Offset stop working.

Below is a plot of relation between Skew and rotation waveform.

Image of plot of relation between `Skew` parameter and rotation waveform. The equation of waveform is `exp(skew * sin(ω * t))`.

Change Log

Old Versions

License

FDN64Reverb is licensed under GPLv3. Complete licenses are linked below.

If the link above doesn’t work, please send email to ryukau@gmail.com.

About VST

VST is a trademark of Steinberg Media Technologies GmbH, registered in Europe and other countries.