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Update: 2020-06-15

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LightPadSynth is a lightweight version of CubicPadSynth. For efficiency, interpolation is changed to linear. Also pitch modulation is omitted. Instead, a delay is added for each voice.

LightPadSynth requires CPU which supports AVX or later SIMD instructions.

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 is an additional control for number sliders used for Octave, Seed etc.

Control with many blue vertical bars (BarBox) have some keyboard shortcuts. LFO Wave on Main tab and Gain, Width, Pitch, Phase on Wavetable tab are using BarBox. Shortcuts are enabled after left clicking BarBox and mouse cursor is on the inside of BarBox. Cheat sheet is available on Infomation tab.

Input Control
Ctrl + Left Drag Reset to Default
Shift + Left Drag Naive Draw (Skip bars between frames)
Right Drag Draw Line
a Alternate Sign
d Reset Everything to Default
D Toggle Min/Mid/Max
e Emphasize Low
E Emphasize High
f Low-pass Filter
F High-pass Filter
i Invert Value (Preserve minimum)
I Invert Value (Minimum to 0)
n Normalize (Preserve minimum)
N Normalize (Minimum to 0)
p Permute
r Randomize
R Sparse Randomize
s Sort Descending Order
S Sort Ascending Order
t Subtle Randomize (Random walk)
T Subtle Randomize (Converge to 0)
z Undo
Z Redo
, (Comma) Rotate Back
. (Period) Rotate Forward
1 Decrease
2-9 Decrease 2n-9n

Some BarBox has scroll bar to zoom in. Scroll bar has handles on left end and right end. To control zoom, use Left Drag on one of the handle. Scroll bar also has following controls:


Pressing Refresh LFO or Refresh Table button stop sound. They also stop all midi notes.

Wavetable Specification

128 wavetables are generated. The number 128 comes from MIDI note number range. The indices of wavetables correspond to MIDI note numbers.

When tuning is not exact, an index will be truncated to semitones. For example, if MIDI note number is 60 and tuning is -20 cents, index becomes floor(60 - 0.20) = 59. Thus, 59th wavetable will be used.

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.


Main Tab


A, D, S, R

Gain envelope parameters.


Master output gain.


Naive 3-pole low-pass filter.


Cutoff frequency of the filter.


Resonance of the filter. Be careful when turning to right, output will be loud.


When set to right-most, cutoff frequency is set to the frequency of a note. When set to left-most, it only use the value of Cutoff.

A, D, S, R, Amount

Filter envelope parameters. Amount changes the amount of modulation to cutoff.


Octave, Semi, Milli

Changes master pitch.

Milli is 1/1000 of semitone or 1/10 cent.

ET, A4 [Hz]

Changes tuning.

ET stands for equal temperature. Note that when ET is less than 12, some notes becomes silent due to frequency becomes too high or too low.

A4 [Hz] is frequency of note A4.



Number of voices used by unison.

To avoid interruption of release, increase the number of nVoice in Misc. section. Note that increasing nVoice consumes more resources.

Detune, Random Detune

Detune is the difference of pitch between voices used in a unison.

When Random Detune is checked, amount of detune changes for each note-on.

random = RandomDetune ? rand() : 1
detune = pitch * (1 + random * unisonIndex * Detune)

Amount of randomization of gain for voices used in a unison.


Amount of randomization of phase for voices used in a unison.

This parameter makes no effect when Reset in Phase section is checked.

Spread, Spread Type

Spread is an amount of stereo spread for a unison.

Spread Type provides options to assign panpot values according to voice pitch.



Initial phase of oscillator.


When checked, resets oscillator phase to the value set by Phase.


When checked, randomize phase for each note-on. In this case, value of Phase becomes range of randomization.



Time length to change some parameter value to current one. Unit is in second.

List of parameters related to Smooth. * represents wild card.


Maximum polyphony. Lowering the number of this option reduces CPU load.


Random seed. This value change random number sequence.

LightPadSynth has 2 random number generaters. One is used in Main tab and the other is in Wavetable tab.



Mixing ratio of filter output and delay output.


Feedback of a delay. Positive feedback when turning right. Negative feedback when turning left.


Attack time of gate between filter output and delay.

Semi, Milli

Delay time relative to note frequency. Following equation is used.

delayTime = 1 / (noteFreq * pow(2, (semi + 0.001 * milli) / 12))


Tempo, Multiply

Sets LFO frequency according to current tempo. Lower numeral represents the length of note. Upper numeral is the number of notes.

Value of Multiply is multiplied to the frequency calculated from Tempo.

// (60 seconds) * (4 beat) = 240
lfoFrequency = Multiply * (BPM / 240) / (TempoUpperNumeral / TempoLowerNumeral)

LFO frequency modulation amount.


Changes cutoff freequency of low-pass filter for LFO.


Type of LFO wavetable interpolation.

Refresh LFO

Refresh LFO wavetable based on current value of LFO Wave.

Note that refreshing wavetable stops sound. It also interrupts MIDI notes.

LFO Wave

LFO waveform.

Wavetable Tab

Overtone Controls


Gain of profile.


Width of profile.


This value is multiplied to profile center frequency.


Range of randomization for the phase of profile.


Base Freq.

Fundamental frequency of wavetable. Note that if this value is small, master pitch becomes out of tune.

Multiply, Modulo

Changes profile center frequency.

profileCenterFrequency = mod(
  BaseFreq * profileIndex * overtonePitch * Multiply,
  440 * pow(2, (Modulo - 69) / 12)



Scaling factor to shrink/expand the spectrum along to frequency axis.


Shift spectrum along to frequency axis.


When this value is higher than 1, it changes the shape of profile like a comb. The value specifies interval between peaks.


Changes profile shapes by using the value of Shape as an exponent.

shapedProfile = powf(profile, shape);



When checked, phase of a profile becomes an uniform value.



Random seed. This value change random number sequence.

LightPadSynth has 2 random number generaters. One is used in Main tab and the other is in Wavetable tab.


Size of a wavetable. The power of 2 values can be selected from 2^10 to 2^21.

The value inside parentheses indicates number of bytes in a sum of all wavetables. A number of bytes is calculated with following equation.

bytes = 4 * 128 * BufferSize



Exponent for Gain in overtone control.

profileGain = pow(Gain, Gain^)

Multiplier for Width in overtone control.

profileWidth = Width * (Width*)

Refresh Table

Refresh PADsynth wavetable based on current configuration of Wavetable tab.

Note that refreshing wavetable stops sound. It also interrupts MIDI notes.

Change Log

Old Versions


LightPadSynth 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.