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Update: 2023-12-02

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UltraSynth is an ordinary synthesizer except 64-fold oversampling that is the same one used in UltrasonicRingMod. Because of the high oversampling ratio, modulation sound is okay. However CPU load is high.

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.


Feel free to contact me on GitHub repository or

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



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:

XY pad provides following controls:

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.


Mixing ratio of full wave rectified signal.


Mixing ratio of the signal distorted by square root.

A, D, S, R

Gain envelope parameters.


UltraSynth has 2 oscillators. The parameters of each oscillator matchs to X or Y axis of X-Y pad.


Oscillator pitch.

The value is not visible on GUI, but the unit is cent, which is 1/100 of a semitone.

Wave Shape

Oscillator wave shape.

When Saw-Pulse is 0, the value [0, 0.5, 1] matches to [Upward Sawtooth, Triangle, Downward Sawtooth]. When Saw-Pulse is 1, the value becomes the duty ratio of pulse wave.


Mixing ratio of sawtooth and pulse wave in a oscillator.

When Saw-Pulse is 0, oscillator outputs sawtooth wave. When Saw-Pulse is 1, oscillator outputs pulse wave.

X Oct., Y Oct.

Pitch of oscillator in octave.


Mixing ratio of 2 oscillators.

When Mix is 0, you can only hear oscillator X output. When Mix is 1, you can only hear oscillator Y output.


Modulation gain of filter output to oscillator X.

Cross PM

Cross phase modulation amount.

Horizontal (X) axis constrols Y to X modulation, and vertical (Y) axis controls X to Y modulation.

Feedback PM

Feedback phase modulation amount.

Horizontal (X) axis constrols X to X modulation, and vertical (Y) axis controls Y to Y modulation.


Lowpass filter parameters.


Cutoff frequency of lowpass filter.


Q factor of lowpass filter.

A, D

Cutoff envelope parameters.


Modulation amount from envelope to cutoff frequency.


Cutoff tuning ratio depending on the pitch of note.

When set to leftmost, cutoff frequency doesn’t change regardless of the pitch of note. When set to rightmost, cutoff frequency precisely follows the pitch of note.


Semitone, Cent

Pitch in semitone or cent. 1 semitone equals to 100 cents.

Equal Temp., A4 [Hz]

Equal Temp. is abbreviation of equal temperament (ET). When Equal Temp. is 12, then the tuning becomes standard 12 ET. Setting Equal Temp. to less than 12 might increase the range of note that doesn’t change sound, or doesn’t output sound. This is due to the internal pitch becomes too high or too low.

A4 [Hz] is freqeuncy of note A4.

P.Bend Range [st.]

Range of pitch bend in semitone.



Rate of LFO.

When Sync. is turned off, Rate becomes the frequency of LFO. When Sync. is turned on, Rate becomes the multiplier to the interval of synchronization. For example, if Rate is 2 and Sync. is turned off, LFO cycles at 2 Hz. If Rate is 2 and Sync. is turned on, the interval of synchronization becomes half (1/2).


LFO distortion amount.

The wave shape becomes close to square wave when Shape is set to rightmost.


When checked, it resets LFO phase to 0 for each note-on.


When checked, it enables tempo synchronization.

Sync. Upper, Sync. Lower

These are the numbers on the right side of Sync. checkbox. They indicates the interval of synchronization in beats.

Note that Sync. Upper and Sync. Lower are not time signature, but beats in fractional number. For example, if time signature is set to 3/4, and Sync. Upper and Sync. Lower are both set to 1, LFO cycles 3 time in a bar.

Following is the calculation of the interval of synchronization.

syncIntervalInBeats = (Sync. Upper) / (Sync. Lower).

LFO modulation amount for oscillator pitch.


LFO modulation amount for Oscillator -> Mix.


LFO modulation amount for filter cutoff frequency.

>Pre Sat.

LFO modulation amount for the amplitude of signal right before passing Sat..

>X Shape, >Y Shape

LFO modulation amount for Wave Shape.


Phase Reset

When checked, it resets oscillator phase at note-on, only if gain envelope is resting.

Gain envelope rests when the output value after release becomes sufficiently small. Therefore, if note-on is given when you are still perceiving release of the previous note, the oscillator phase won’t reset because gain envelope is not resting. Also note that when release time is long, it’s hard to determine if gain envelope is resting or not by using hearing.


Time to slide the pitch of latest note.

Change Log

Old Versions


UltraSynth 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.