Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.
Download on the App StoreAudiobus is the app that makes the rest of your setup better.
StreamByter/MIDIFIRE
StreamByter is a powerful scripting language for writing MIDI processing scripts from Audeonic. There is a standalone app called MidiFire that lets you create and use StreamByter scripts as well as an AU that can host them. MIDI Designer Pro can also make use of StreamByter scripts.
Post links to related threads and videos here.
The developer is quite active on a forum devoted to MidiFire and StreamByter and is very helpful in helping develop scripts. The forums is found at: http://audeonic.boards.net
Comments
YouTube channel devoted to MidiFire:
@gmslayton has posted a great tutorial here about using StreamByter as a transposition tool:
https://forum.audiob.us/discussion/31496/transpose-fugue-machine-or-any-sequencer-with-streambyter for transposing FugueMachine sequences or sequences from any sequencer.
You can post links to forum posts that have interesting StreamByter scripts. You can copy a link to a particular post by tapping and holding on the date hyperlink that appears at the beginning of each message (or by control-clicking or right-clicking on the date).
Script for distributing simultaneous notes to any number of mono synths (or midi channels):
https://forum.audiob.us/discussion/30081/streambyter-script-distribute-polyphonic-midi-to-n-channels-with-m-voices-each#latest
"MIDI BUFFER AND RELEASE SCRIPT"
Buffer up "n" MIDI notes and then release once buffer is full:
https://forum.audiob.us/discussion/comment/630730/#Comment_630730
Here’s a chart to convert notes to hex or MIDI notes to hex.