Polyphonic Synthesizer

VAPolyQuad is a virtual analog polyphonic synthesizer for iPhone, iPad and Mac. It features 8 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.


Single voice of the synthesizer features four oscillators, two mixers, two resonant high pass filters, two resonant  low pass filters, two amplifiers, four ADSR envelopes and four LFOs. 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


  • Virtual analog 8 voice polyphonic synthesizer.
  • Four oscillators per voice and flexible audio signal and control signal routing.
  • Keyboard Control Routing
  • Two type of Lowpass filter, cascaded OTA model and Sallen-key model.


  • 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.

VAPolyQuad is available now on the Apple App Store.


User Guide (V1.0)



8 voice virtual analog polyphonic synthesizer


  • Continuously variable wave shape (triangle, sawtooth, square)
  • Sub: Square, one octave lower (oscillator 1&3)
  • Pulse width for triangle and square (oscillator 1&3)
  • Pulse width for square (oscillator 2&4)
  • Hard Sync (oscillator 1 to oscillator 2, oscillator 3 to oscillator 4)
  • Keyboard on/off (oscillator 2&4)
  • Low frequency mode (oscillator 2&4)
  • Tuning +/- 24 semitones
  • Fine tuning +/- 50 cents (oscillator 2&4)


  • 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
  • Key Follow: From 100% to 25% (envelope length)

Oscillator Modulation

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


  • High pass filter: -12 dB per octave
  • Low pass filter: -12 dB per octave, -24 dB per octave
  • Frequency modulation: ADSR, 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


  • Steps:            16 steps per bar
  • 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