Bitimbral Polyphonic Synthesizer

VAPolyMkII is a virtual analog bitimbral polyphonic synthesizer for iPhone, iPad and Mac. It features 16 voice synthesizer, effects, sequencer and audio visualization tools. It operates as a stand alone or as an AudioUnit Extension (AUv3).  Stand Alone supports Ableton Link, MIDI and audio file export.


The synthesizer consists of two 8 voice synthesizer, which features two oscillators, two ADSR envelopes, resonant high pass and low pass filter and an amplifier per voice. The oscillators features continuously variable wave shape and wide variety of modulation. The filters are modeled on the Sallen-Key filter circuit and cascaded OTA filter circuit for classic analog sound.


The Effects include delay, chorus, flanger, reverb, eq and compressor.


The sequencer features piano roll and parameter automation editor to program 16 bar pattern per clip.

Main Features


  • Two virtual analog 8 voice polyphonic synthesizer with dedicated UI.
  • Two type of Lowpass filter, cascaded OTA model and Sallen-key model.
  • Patch points for modulation.


  • 16 bar patterns per clip. Total 8 clips.
  • Piano Roll and Parameter automation.

Audio Export

  • Linear PCM format (AIFF, WAV and CAF) and compressed format (AAC)


  • Support MIDI 2.0
  • Support iCloud Drive.
  • Support Ableton Link, Bluetooth MIDI, MIDI In / Out.
  • Support Audio Unit Extension (AUv3)
  • Works on iPhone, iPad and Mac.

System Requirements

  • iOS 16.6 or later
  • macOS 13.6 or later
  • For iOS devices, A13 Fusion or above is recommended.
  • AudioUnit Extension (AUv3) requires host application which support AudioUnit Extension.
  • AudioUnit Extension (AUv3) is supported by Apple Garage Band on iOS and macOS, and Apple Logic on Mac.  For any other DAW, it depends on the application and some of them don’t support AudioUnit Extension (AUv3).
  • *Apple, Mac and GarageBand are trademarks of Apple Inc., registered in the U.S. and other countries.
  • *Ableton and Link are trademarks of Ableton AG.
  • *All products, companies and standard names are trademarks or registered trademarks of their respective holders.
  • * Ableton Link requires Local Area Network connections.

VAPolyMkII is available now on the Apple App Store.


User Guide (V1.3.0)



16 voice virtual analog bitimbral polyphonic synthesizer


  • Continuously variable wave shape (triangle, sawtooth, square)
  • Sub: Square, one octave lower (oscillator 1)
  • Pulse width for triangle and square (oscillator 1)
  • Pulse width for square (oscillator 2)
  • Hard Sync (oscillator 1 to oscillator 2)
  • Keyboard on/off (oscillator 2)
  • Low frequency mode (oscillator 2)
  • Tuning +/- 24 semitones
  • Fine tuning +/- 50 cents (oscillator 2)


  • Wave shape: sine, saw, down saw, square, triangle, random
  • Frequency Range:  From 0.04Hz to 42.2Hz
  • Amplitude modulation by ADSR envelope

ADSR Envelope

  • Attack time:    From1ms to 6 sec
  • Decay time:    From 1ms to 10 sec
  • Sustain level:  From 0 to 100%
  • Release time: From 1ms to 10 sec
  • Delay time: From 0ms to 10 sec


  • LFO:   frequency, shape, pulse width, amplitude
  • Env:    frequency, shape, pulse width, LFO amplitude
  • Xmod: frequency and shape
  • Ring:   oscillator 1 output and oscillator 2 output
  • Frequency modulation mode: linear / exponential


  • Resonant High pass filter: -12 dB per octave
  • Resonant Low pass filter: -12 dB per octave
  • Filter envelope: ADSR(Env1/Env2)
  • Frequency modulation by LFO
  • Key Follow
  • Routing: Cascade / Parallel


  • Envelope: ADSR
  • Amplitude modulation by LFO
  • Pan modulation by LFO
  • Mute: On / Off


  • Modulation Wheel
  • Pitch Bend Wheel


  • Type: Up, Down, Up&Down. Random
  • Frequency: From 1 Hz to 20 Hz

Portamento (Glide)

  • Time: From 10 ms to 10 second


  • Loop Length: from 1 bar to 16 bars
  • Clip:               8 clips
  • Tempo:           from 20 BPM to 999 BPM
  • Host Sync:     On and Off


  • Delay, Chorus, Flanger, Reverb, EQ and Compressor

*Appearance and specification of products are subject to change without notice.

Release Note

Version 1.0

  • Initial release

Version 1.0.1

  • Fixed a problem that system sample rate change is handled incorrectly.

Version 1.0.2

  • Added version information in global setting.
  • Added undo for recording, file new and file open.
  • Fixed a problem that app crash by tapping on Map MIDI CC button in setting panel when effects are displayed.
  • Fixed a problem that state is not restored correctly.
  • Fixed a problem that preset name is not updated when clip changed during the playback.
  • Fixed a problem that value of Delay Time, LFO Freq (C/F and Reverb) and Room Size (Reverb) doesn’t show sync rate when sync switch is on.
  • Fixed a problem that undo doesn’t work in Stand Alone Setting Panel correctly.
  • Fixed a problem that user interface elements are scaled incorrectly.

Version 1.0.3

  • Fixed a problem that edit menu appears by three finger tap.
  • Fixed a problem that preset manager behave erratic when loading plugin presets.
  • Fixed a problem that MIDI settings are not updated when a user preset is loaded.

Version 1.0.4

  • Fixed a problem that save file dialog moves up and disappear when keyboard shows up on iPad.
  • Fixed a problem that plugin preset name is displayed incorrectly when other presets are deleted.
  • Fixed a problem that MIDI Pitch Bend Message is handled incorrectly.

Version 1.0.5

  • Fixed a problem that buttons are displayed with unexpected style on some devices.
  • Fixed a problem that edit menu appears by three finger tap.

Version 1.0.6

  • Added an ability for list to scroll to the selection.
  • Fixed a problem that buttons don’t trigger when tapped on space around icon.
  • Fixed a problem that scroll bar and range selector bar of piano roll editor are not worked properly.
  • Fixed a problem of three finger double tap undo gesture.
  • Fixed a problem that pitch changes when thumb of pitch wheel is touched down before it is moved.
  • Fixed a problem that note is turned off when previously pressed key is released in unison mode.

Version 1.0.7

  • Added an ability for keyboard to scroll.
  • Improved behavior of key holding.
  • Improved scrolling behavior of sequence editor.

Version 1.0.8

  • Improved restoration of the keyboard scroll position.
  • Improved undo and redo.
  • Fixed a problem of transition animation.

Version 1.0.9

  • Improved behavior of undo and redo.
  • Improved handling of computer keyboard input.
  • Added buttons for editing menu in sequencer editors.
  • Fixed a problem that app crash when adjusting note range in piano roll editor in certain condition.
  • Fixed a problem that app crash when adjusting note length in piano roll editor in certain condition. 

Version 1.0.10

  • Improved parameter value slider in top bar. Parameter menu is now enabled by double tap.
  • Improved user interaction of patch bay editor.
  • Fixed a problem of note label in piano roll when Heptatonic mode is selected.

Version 1.1.0

  • Added an option to show compact keyboard on iPhone.
  • Fixed a problem that changing destination of patch cable doesn’t work properly.
  • Fixed a problem of state restoration.

Version 1.2.0

  • Added 150 factory presets.
  • Fixed a problem that audio visualizer doesn’t update properly when note is changed.
  • Fixed a problem that patch connections are not updated when factory preset is changed.

Version 1.3.0

  • Added legato option When unison mode is turned on. Legato is turned on when value of the glide time is greater than minimum value. 
  • Fixed a problem that visualizer doesn’t update properly when unison mode is on.
  • Fixed a problem that envelope doesn’t reset by note off event in some cases.
  • Fixed a problem that arpeggio doesn’t work properly when unison switch is turned on.
  • Fixed a problem that preset doesn’t be loaded properly when clip is changed.
  • Fixed a problem that record count in doesn’t work correctly.
  • Fixed a problem that recording doesn’t start from loop start position.

Version 1.3.1

  • Fixed a problem that editing function of clip editor doesn’t work correctly.