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.
Alexis Control Hub - any alternatives?
I see this has been long discontinued, I still have one, but I am asking in case it ever fails.
anything about that matches it and how it works (IE passive, no power needed)
Comments
From what I can see the Alesis (not Alexis) control hub is a Midi and Audio interface. None of those interfaces is passive. They all require power, and if not via an additional PSU (Wall Wart), then via USB. It depends on your setup if your iPad can power such an interface directly, or if you need to put a powered USB hub between your iPad and the device. This is often the case for iPads with lightning connector and camera/USB adapter. As for a replacement, there are plenty to choose from. In my case I use a Behringer Uphoria UMC204HD.