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Update: 2024-09-28

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TrapezoidSynth is a monophonic synthesizer equipped with 2 trapezoid oscillator. Trapezoid oscillator is based on PTR (Polynomial Transition Regions) and it has a drawback that increasing noise at high frequency. Therefore 8 times oversampled. 2 pitch shifters are added to make some chord.

full package contains following builds.

Linux build is built on Ubuntu 24.04. If you are using distribution other than Ubuntu 24.04, 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 ryukau@gmail.com.

You can fund the development through paypal.me/ryukau.

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.

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

On Ubuntu 24.04, 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.

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.

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 com.apple.quarantine /path/to/PluginName.vst3
xattr -rc /path/to/PluginName.vst3

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.

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.

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. To use, copy the text to style.json.

Below is an 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"
}

Following is a list of font options.

System font can be used as fontFamily. To use different fonts for different plugins, place *.ttf file into custom font path: *.vst3/Contents/Resources/Fonts.

Notice: If the combination of fontFamily, fontBold, fontItalic does not exist 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 exist, 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.

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:

It is recommended to insert high-pass when setting SlideType to Reset to 0.

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.

Semi

Change oscillator pitch in semitone.

Cent

Change oscillator pitch in cent. 100 cent = 1 semitone.

Slope

Change left and right side of slope of trapezoid.

PW

Pulse width. Change length of upper side of trapezoid.

Drift

Modulate pitch with white noise.

Feedback

Modulate phase of Oscillator 1 with feedback signal.

osc1Phase += Feedback * (osc1 + OscMix * (osc2 - osc1))

Overtone

Multiply the frequency of oscillator by number of Overtone.

PM

Modulate Osillator 1 phase with Oscillator 2 output.

Retrigger

When checked, reset envelope for each note on. When not checked, reset envelope only if the number of pressed key is changed from 0 to 1 or more.

A

Attack time in seconds.

D

Decay time in seconds.

S

Sustain level.

R

Release time in seconds.

Curve

Change envelope curve.

Gain

Master output gain.

Order

TrapezoidSynth is using 8 of serially connected first order filter. Order changes where to get the signal from the filter.

Cut

Cutoff frequency in Hz.

Res

Resonance.

Sat

Filter saturation.

filterInput = tanh(Sat * (input + Res * filterOutput))
Env>Cut

Modulation amount from Filter Envelope to Cut.

Key>Cut

Modulation amount from note pitch to Cut.

+OscMix

Modulation amount from mixed signal of Oscillator 1 and Oscillator 2 to Cut.

>Octave

Modulation amount from Filter Envelope to pitch in octave.

OscMix

Ratio of Oscillator 1 and Oscillator 2. When turned to left-most, output becomes only the signal from Oscillator 1.

Octave

Change pitch in octave.

Smooth

Interpolation time in seconds from previous value to current value. Following parameters are affected by Smooth.

Retrigger

When checked, reset envelope for each note on. When not checked, reset envelope only if the number of pressed key is changed from 0 to 1 or more.

Attack

Modulation envelope attack time in seconds.

Curve

Modulation envelope curve.

>PM

Modulation amount from modulation envelope 1 to Oscillator2.PM.

>Feedback

Modulation amount from modulation envelope 2 to Oscillator1.Feedback.

>LFO

Modulation amount from modulation envelope 2 to LFO.Freq.

>Slope2

Modulation amount from modulation envelope 2 to Oscillator2.Slope.

>Shifter1

Modulation amount from modulation envelope 2 to Shifter 1 pitch.

Semi

Change amount of pitch shift in semitone.

Cent

Change amount of pitch shift pitch in cent. 100 cent = 1 semitone.

Gain

Output gain of pitch shifter.

LFOType

4 waveforms are available for LFO.

Tempo

Synchronize LFO frequency to tempo.

Freq

LFO frequency.

Shape

Change LFO wave shape.

>Pitch

Modulation amount from LFO to Oscillator 1 pitch.

>Slope1

Modulation amount from LFO to Oscillator1.Slope.

>PW1

Modulation amount from LFO to Oscillator1.PW.

>PW1

Modulation amount from LFO to Filter.Cut.

SlideType

3 type of pitch slide is available.

Time

Time of pitch sliding.

Offset

Oscillator 2 slide time with respect to Oscillator 1 slide time.

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

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

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