midi probability gate filter

Takes a stream of busy, repetitive MIDI notes and selectively mutes some of them to make it more interesting!

midiFILTr-PG is an Audiobus 3 MIDI filter gate effect that is quick to configure, easy to use, simple but powerful.

Filter other iPad music apps via Audiobus 3 or CoreMIDI, or external MIDI sequencers with a USB-MIDI interface.

Created by the developer behind the pioneering iOS CoreMIDI music apps FunkBox and Little MIDI Machine.


  • Gate, Note and Sequencer modes
  • Gate is a flat % chance to let a note through
  • Note sets the % based on the note's pitch
  • Sequencer has an 8 step sequence of %s
  • Easy to use Audiobus 3 MIDI filter effect
  • Can also be configured with CoreMIDI


  • Create a very busy musical sequence and send it through midiFILTr-PG to thin it out
  • Create subtle random variations by only muting a few notes or pitches
  • Create polyrhythmic sequences using the sequencer to mode gate sequences with a different sequence length