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.
Audiokit Synth one, lag issue switching app, solved by "always active"
@analog_matt digging into this great synth, I found out I needed to activate "always active" to be able to switch between apps without lag into this synth. (with the warning message that it may drain the battery.)
As I'm aware of that, I'd like this parameter to be saved in settings all the time...
Every time I reload the synth I need to activate this, and that parameter is also not saved into the preset.
Thanks for considering this feature 
BTW, program change are working marvelously
Comments
I just updated Synth One today and for the first time I've started to notice bad lag within the app itself, with nothing else running in background. (on iPad Pro 2)
Every minute or so it'll completely ignore several notes when playing the built in keyboard. Happens with or without the new anti-aliasing featured turned on, but only seems to happen when I'm programming my own sounds ... All the patches seem to work fine so long as I don't edit them ., so I'm wondering if it might be a bug in some of the controls causing it to hang..
Anyone else notice this?
Thanks for the information, @crony, @AnimalHeadSpirit, appreciate it!