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Update: 2023-12-02

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NarrowingDelay is a delay with serially connected pitch shifter and frequency shifter on feedback path. The spectrum of input signal can be narrowed or expanded for each feedback. It is more suitable for sound without stable pitch. Note event can be used to control frequency shift amount.

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:

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.

Note Event Input

NarrowingDelay can receive note events to control the amount of frequency shift. Following the equation to calculate the amount of frequency shift.

# `note` is MIDI note number.
(Frequency Shift) = 2^((note - 69) / 12) * ((Value of Shift [Hz]) + lfo).


Characters inside of square brackets [] represents unit. Following is a list of units used in NarrowingDelay.



Gain for bypassing input signal.


Gain for output signal comes out from NarrowingDelay.


Feedback gain.


Cutoff frequency of highpass (HP) or lowpass (LP) filter on feedback path.

Delay Time [s]

Buffer length of pitch shifter. The value is not exact, but a rough indication.

When the value of Shift \[oct.\] is not 0.0, delay time is doesn’t match the displayed value because of the change of buffer playback speed.

Shift [oct.], Shift [Hz]

Shift [oct.] is the amount of pitch shift, and Shift [Hz] is the amount of frequency shift.

To input frequencies, pitch shift performs multiplication, and frequency shift performs addition. It can be written as following equation.

(Output Frequency) ~= (Input Frequency) * 2^(Pitch Shift) + (Frequency Shift).

This means that when the amount of pitch shift is less than 0.0, spectrum becomes narrower. And when the amount of pitch shift is greater than 0.0, spectrum becomes broader than the original. NarrowingDelay was created with the idea that if the fundamental frequencies of the input and output are matched by frequency shifting after narrowing the spectrum, it might produce an interesting sound.

The frequency shift algorithm used in NarrowingDelay can’t decrease frequency. Therefore a procedure that decreasing frequency after broadening spectrum can’t be used to match fundamental frequency.


LFO modulation amount. Following 3 parameters can be targeted.


L-R Offset

LFO phase offset between stereo channels.


A value that is added to LFO phase.

To manually control LFO phase, set Rate to leftmost to stop LFO, then change the value of Phase. Also, the value of Smoothing affects the response time when Phase is changed.

Clip, Skew

LFO waveform parameters. Computation is done as following.

# Range of `phase` is [0, 1).
wave = sin(2 * π * phase^Skew).
lfo = clamp(Clip * wave, T(-1), T(1)).

When checked, it enables tempo synchronization (tempo sync). LFO phase also synchronize to the exact position derived from sync interval, and time passed from the start of playback.

When not checked, LFO behaves as same as if synchronizing to 120 BPM. It also disables LFO phase sync.

Tempo Upper

Numerator of sync interval.

LFO synchronizes to 1 bar when (Tempo Upper) / (Tempo Lower) is 1/1. 1/4 synchronizes to 1 beat when time signature of 4/4. Note that Rate multiplies the sync interval.

Following is the equation to calculate sync interval.

syncInterval = (Rate) * (Tempo Upper) / (Tempo Lower);
Tempo Lower

Denominator of sync interval.

Note that Rate multiplies the sync interval.


Multiplier to sync interval.

Rate is convenient when changing sync interval while keeping the values of Tempo Upper and Tempo Lower.

Smoothing [s]

Paramter smoothing time in seconds.

For example, if the value of Smoothing is set to 0.01 or something short, the change of parameter almost immediately applies. So it sounds more snappy, but may introduce audible pop noise. On the other hand, if the value of Smoothing is set to 1.0 for example, the change of parameter is only slowly followed.


Oversampling ratio.

Change Log

Old Versions


NarrowingDelay 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.