Update: 2020-09-02
CubicPadSynth is a wavetable synthesizer which uses PADsynth algorithm to generate oscillator tables. Cubic interpolation is used to get smooth sound even at inaudible low frequency range. LFO waveform can be directly drawn.
CubicPadSynth 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 ryukau@gmail.com.
Linux build is built on Ubuntu 18.0.4 and tested on Bitwig and Reaper. If you are using distribution other than Ubuntu 18.04, plugin will not likely run. In this case, please take a look at build instruction.
Place *.vst3 directory to:
/Program Files/Common Files/VST3/ for Windows.$HOME/.vst3/ for Linux./Users/$USERNAME/Library/Audio/Plug-ins/VST3/ for macOS.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:
/Users/$USERNAME/Documents/VST3 Presets/Uhhyou$HOME/.vst3/presets/Uhhyou/Users/$USERNAME/Library/Audio/Presets/UhhyouPreset directory name must be the same as the plugin. Make Uhhyou directory if it does not exist.
If DAW doesn’t recognize the plugin, try installing C++ redistributable (vc_redist.x64.exe). Installer can be found in the link below.
On Ubuntu 18.0.4, those packages are required.
If DAW doesn’t recognize the plugin, take a look at Package Requirements section of the link below and make sure all the VST3 related package is installed.
REAPER on Linux may not recognize the plugin. A workaround is to delete a file ~/.config/REAPER/reaper-vstplugins64.ini and restart REAPER.
When trying to run plugin first time, following message may appear on macOS.
<PluginName>.vst3 is damaged and can't be opened. You should move it to
the Trash"In this case, open terminal and try running following command to unzipped .vst3 directory.
Plugin may be considered as unsigned/un-notarized application. In this case, try following the steps below.
sudo spctl --master-disable.Beware that steps above degrades security of your system. To revert the settings, follow the steps below.
sudo spctl --master-enable.At first time, create color config file to:
/Users/USERNAME/AppData/Roaming/UhhyouPlugins/style/style.json on Windows.$XDG_CONFIG_HOME/UhhyouPlugins/style/style.json on Linux.
$XDG_CONFIG_HOME is empty, make $HOME/.config/UhhyouPlugins/style/style.json./Users/$USERNAME/Library/Preferences/UhhyouPlugins/style/style.json on macOS.Below is a example of style.json.
{
"fontPath": "",
"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"
}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.
fontPath: Absolute path to *.ttf font file. Not implemented in VST 3 version.foreground: Text color.foregroundButtonOn: Text color of active toggle button. Recommend to use the same value of foreground or boxBackground.foregroundInactive: Text color of inactive components. Currently, only used for TabView.background: Background color.boxBackground: Background color of inside of box shaped components (Barbox, Button, Checkbox, OptionMenu, TextKnob, VSlider).border: Border color of box shaped components.borderCheckbox: Border color of CheckBox.borderLabel: Line color of parameter section label.unfocused: Color to fill unfocused components. Currently, only used for knobs.highlightMain: Color to indicate focus is on a component. Highlight colors are also used for value of slider components (BarBox and VSlider).highlightAccent: Same as highlightMain. Used for cosmetics.highlightButton: Color to indicate focus is on a button.highlightWarning: Same as highlightMain, but only used for parameters which requires extra caution.overlay: Overlay color. Used to overlay texts and indicators.overlayHighlight: Overlay color to highlight current focus.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 |
|---|---|
| Left Drag | Change Value |
| Shift + Left Drag | Change Value (Snapped) |
| Ctrl + Left Drag | Reset to Default |
| Ctrl + Shift + Left Drag | Change Value (Skip Between Frames) |
| Right Drag | Draw Line |
| Shift + Right Drag | Edit One Bar |
| Ctrl + Right Drag | Reset to Default |
| Ctrl + Shift + Right Drag | Toggle Lock |
| 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) |
| l | Toggle Lock under Mouse Cursor |
| L | Toggle Lock for All |
| 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 |
Snapping is not available for all BarBox. If you’d like to have snapping for certain BarBox, feel free to open issue to GitHub repository.
Edit One Bar with Shift + Right Drag holds a bar under the cursor when mouse right button is pressed. Then only changes that one bar while holding down mouse right button.
Toggle Lock with Ctrl + Shift + Right Drag behaves as line edit. When right mouse button (RMB) is pressed, it holds the opposite state of the bar below mouse cursor, then use the state for the rest of bars. For example, if RMB is pressed on a locked bar, dragging unlocks bars while holding down RMB.
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.
Length of a wavetable is 2^18 samples.
136 band-limited wavetables are generated for each MIDI note. Pitch bending is supported as high as 21100 Hz. 21100 Hz is derived from MIDI note number 136. Frequency of MIDI note number 137 is higher then 22050 Hz. That’s why 136 is selected.
When fundamental frequency of a note is lower than 8.18 Hz, some overtones on high frequency may lost. However, cubic interpolation may cause noise which makes those frequency not to be 0.
noteToFreq(note) := 440 * Math.pow(2, (note - 69) / 12)
noteToFreq(0) = 8.175798915643707
noteToFreq(136) = 21096.16364242367
noteToFreq(137) = 22350.606811712252Wavetable is represented as 2D array with size of 136 * 2^18. Bicubic interpolation is used to get the value from the table. Coordinate on time/band-limit axis is determined by phase and frequency of oscillator.
The size of wavetable is large for a synthesizer. Xrun may occur if memory is slow. It may also consume more resources for higher notes because access pattern becomes close to random.
CubicPadSynth uses PADsynth algorithm, which is originated from ZynAddSubFX. Yoshimi is also using PADsynth algorithm.
Passing phase randomized spectrum to IDFT (inverse discrete fourier transform) generates a cyclic waveform which is smooth when connecting an end to another end. PADsynth is utilizing this property.
“Profile” function is used to synthesize spectrum. CubicPadSynth uses normal distribution curve for profile, which is same as original PADsynth algorithm. Center frequency of profile can be set arbitrary. In default, CubicPadSynth uses fundamental frequency set by Base Freq. and its overtones.
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.
Changes master pitch.
Milli is 1/1000 of semitone or 1/10 cent.
Changes tuning.
ET stands for equal temperament. 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.
Gain envelope parameters.
A : Attack time which is the length from note-on to reaching peak value.D : Decay time which is the length from peak value to reaching sustain level.S : Sustain level which is the gain after decay.R : Release time which is the length from note-off to the gain reaching to 0.Master output gain.
This is a psuedo low-pass filter. It shifts to wavetable which contains less overtone to get low-passed output.
Equation to get cutoff frequency is following.
cut = Cutoff * 128
keyFollowRange = Cutoff * (nTable - pitch)
lowpassPitch = (cut + KeyFollow * (keyFollowRange - cut)) - lowpassEnvelope * Amount;
if (lowpassPitch < 0) lowpassPitch = 0
noteToFreq(note) := 440 * Math.pow(2, (note - 69) / 12)
range = noteToFreq(nTable)
lpFreq = noteToFreq(midiNote + lowpassPitch)
ntFreq = noteToFreq(midiNote)
cutoffFrequency = (1 + (range - lpFreq) / range) * ntFreq128 used to calculate lpCut is an arbitrary value which came from MIDI note number range + 1. nTable is set to 136.
Changes filter cutoff frequency.
When set to right-most, cutoff frequency is set to make the number of overtone to be almost same regardless of pitch of note. When set to left-most, it only use the value of Cutoff.
Filter envelope parameters. Amount changes the amount of modulation to cutoff.
Pitch envelope parameters.
Changes the sign of pitch envelope output.
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 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 is an amount of stereo spread for a unison.
Spread Type provides options to assign panpot values according to voice pitch.
Alternate L-R: Alternates Ascend L -> R and Ascend R -> L.Alternate M-S: Alternates HighOnMid and HighOnSide.Ascend L -> R: Ascend pitch from left to right.Ascend R -> L: Ascend pitch from right to left.HighOnMid: Ascend pitch from side to mid.HighOnSide: Ascend pitch from mid to side.Random: Randomize pan. May be biased.RotateL: Rotate to left for each note-on.RotateR: Rotate to right for each note-on.Shuffle: Randomly assign pan which is evenly ordered.Refresh LFO wavetable based on current value of LFO Wave.
Note that refreshing wavetable stops sound. It also interrupts MIDI notes.
Type of LFO wavetable interpolation.
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)When checked, resets LFO phase for each note-on.
LFO frequency modulation amount.
Changes cutoff freequency of low-pass filter for LFO.
LFO waveform.
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.
SGainCutoffKeyFollowSAmountSAmountNegativeTempoMultiplyAmountLowpassPhaseMaximum polyphony. Lowering the number of this option reduces CPU load.
When checked, most quiet note is released when the number of active voice is close to maximum polyphony. This can be used to reduce pop noise which occurs on note-on.
Gain of profile.
Width of profile.
This value is multiplied to profile center frequency.
Range of randomization for the phase of profile.
Fundamental frequency of wavetable. Note that if this value is small, master pitch becomes out of tune.
Changes profile center frequency.
profileCenterFrequency = mod(
BaseFreq * profileIndex * overtonePitch * Multiply,
440 * pow(2, (Modulo - 69) / 12)
)When checked, randomize profile center frequency. Ignores values of Pitch in overtone control.
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);Invert spectrum to make the maximum of absolute value to 0, and 0 to the max-abs value. Signs are preserved. Phases aren’t considered.
maxRe = max(abs(spectrumRe))
maxIm = max(abs(spectrumIm))
invertedSpectrumRe = spectrumRe - sgn(spectrumRe) * maxRe
invertedSpectrumIm = spectrumIm - sgn(spectrumIm) * maxImWhen checked, phase of a profile becomes an uniform value.
Random seed. This value change random number sequence.
Exponent for Gain in overtone control.
profileGain = pow(Gain, Gain^)Multiplier for Width in overtone control.
profileWidth = Width * (Width*)Refresh PADsynth wavetable based on current configuration of Wavetable tab.
Note that refreshing wavetable stops sound. It also interrupts MIDI notes.
Refresh Table and Refresh LFO from VST message to parameter. This enables automation and midi mapping.CubicPadSynth 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.