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Update: 2024-01-02

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FDNCymbal is a cymbal sound synthesizer. It can also be used as an effect. Unlike the name, most of metallic texture comes from Schroeder allpass section rather than FDN (feedback delay network). FDN section makes nice impact sound when FDN.Time is short. Tremolo is added to simulate wobbling of cymbal.

full package contains following builds.

Linux build is built on Ubuntu 22.04. If you are using distribution other than Ubuntu 22.04, plugin will not likely to run. In this case, please take a look at build instruction.

macOS package is recommended for macOS user. I can’t purchase Apple Developer Program, therefore installation requires a workaround to bypass Gatekeeper. Details of workaround are written in Installation -> macOS Specific section.


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Move *.vst3 directory to:

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


Notice: Some plugins don’t have presets provided by Uhhyou Plugins.

Presets are included in the plugin package linked at the top of this page. To install presets, follow the steps below.

  1. Download plugin from a link at the top of this page.
  2. Extract downloaded zip file.
  3. Open presets directory placed in extracted package.
  4. Move Uhhyou directory into an OS specific preset directory (see below).

Below is a list of preset directories for each OS.

Preset directory name must be the same as the plugin. If preset directory does not exist, create it.

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 22.04, 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

Important: full package is not confirmed working. When using full, try removing following files.

macOS package doesn’t contain above files. Also, all packages are in “ad-hoc signing” state set by codesign command.

Remove Quarantine

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 one or both of following command to unzipped .vst3 directory. Replace /path/to/PluginName.vst3 according to your install location.

xattr -rd /path/to/PluginName.vst3
xattr -rc /path/to/PluginName.vst3

Bypass Gatekeeper

Plugin may be considered as unsigned/un-notarized application. In this case, open System Preferences, go to Security & Privacy → General, then click the Open Anyway button. The offcial Apple help page linked below has screenshots for the procedure. See “If you want to open an app that hasn’t been notarized or is from an unidentified developer” section.

If the plugin is still not working, try changing install location to /Library/Audio/Plug-ins/VST3/ or /Users/$USERNAME/Library/Audio/Plug-ins/VST3/ whichever still haven’t tried.

If all the above methods do not work, 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.

Applying codesign

Note This section may not relevant to macOS packages. However it’s not verified. (GitHub issue)

To use full package, following command might be used.

sudo codesign --force --deep -s - /path/to/PluginName.vst3

codesign might not be available without installing Xcode.


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.


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

Knob and slider provides following controls:


There’s no compatibility between version 0.1.x and 0.2.x.

When FDN.Feedback is non zero, it may possibly blow up. If that happens, turn FDN.Feedback to leftmost.

When HP Cutoff is moving fast, it may output massive DC. To avoid this, use Shift + Mouse Left Drag or turn up Smooth.

Use as Effect

FDNCymbal can be use as effect, but it’s not intuitive.

When loaded, FDNCymbal is muted to prevent unexpected blow up at initialization. Therefore user must send MIDI note-on to FDNCymbal. Note that output volume could be changed by velocity. Seed and parameters under FDN section are only refreshed when FDNCymbal receives a new note.

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.



Output gain.


Time in seconds to move the value of parameters from previous one to changed one. Below is a list of parameter that is affected by Smooth.


When Stick is on, each note on triggers stick oscillator. Noise density and pitch of tone are related to the pitch of note.


Gain of impulse of stick oscillator.


Gain of sine wave tone of stick oscillator.


Gain of velvet noise of stick oscillator.

Velvet noise is a noise algorithm which output different height of impulses with randomized interval.


Decay time of stick oscillator.



Value of random seed.


When not checked, internal delay time controlled by following 3 parameters will be changed for each note on.


When not checked, stick oscillator output varies for each note.


When not checked, tremolo parameters will be changed for each note on.


When turned on, the signal go through FDN section.


FDN delay time. Internal delay time will be randomized with respect to this value.


FDN section feedback. Beware that if this value is non zero, it’s possible to blow up.


Controls mixing of Cascaded FDN.



Mixing ratio of Schroeder allpass section.

Stage 1 and Stage 2

Stage 1 is serially connected 8 Schroeder allpass. On stage 2, there are 4 Schroeder allpass section connected in parallel. For each section has serially connected 8 Schroeder allpass.


Max delay time of Schroeder allpass section. Internally, delay time will be randomized.


Feedback of Schroeder allpass section.

HP Cutoff

Cutoff frequency of high-pass filter to the output of Schroeder allpass section.


When checked, stage 1 feedback go through tanh saturator.



Mixing ratio of tremolo effect.


Maximum change of amplitude with tremolo.


Tremolo LFO frequency.


Maximum delay time. Delay time is modulated by LFO. This delay simulates doppler effect.

Random (Tremolo)


Amount of randomization to Tremolo.Depth for each note on.


Amount of randomization to Tremolo.Frequency for each note on.


Amount of randomization to Tremolo.DelayTime for each note on.

Change Log

Old Versions

Presets for old versions.


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

If the link above doesn’t work, please send email to

About VST

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