Back to Index

Update: 2020-06-15

Table of Contents


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.

The package includes following builds:

macOS build isn’t tested because I don’t have Mac. If you found a bug, please file a issue to GitHub repository or send email to

Linux build is built on Ubuntu 18.0.4 and tested on Bitwig 3.1.2 and Reaper 6.03. Bitwig 3.1.2 seems to have a bug that occasionally blackouts GUI.



Place *.vst3 directory to:

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


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.

Color Configuration

At first time, create color config file to:

Below is a example of style.json.

  "fontPath": "",
  "foreground": "#ffffff",
  "foregroundButtonOn": "#000000",
  "foregroundInactive": "#8a8a8a",
  "background": "#353d3e",
  "boxBackground": "#000000",
  "border": "#808080",
  "borderCheckbox": "#808080",
  "unfocused": "#b8a65c",
  "highlightMain": "#368a94",
  "highlightAccent": "#2c8a58",
  "highlightButton": "#a77842",
  "highlightWarning": "#8742a7",
  "overlay": "#ffffff88",
  "overlayHighlight": "#00ff0033"

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.


Knob and slider can do:


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.