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.
Midi panel video
I just thought there may be some interest in the video link below. I haven't watched it all the way through yet (it's over an hour long), but there's a panel, hosted by MMA at NAMM 2013, that is a mix of artists and engineers discussing midi. Also, you should be able to find any midi spec on their site, since they're the governing organization, however I have yet to find much on virtual midi.
Comments
That's the 30th anniversary panel. Not just a mix of artists and engineers, THE mix of artists and engineers. The ones who invented and pioneered MIDI.
You won't find anything on the MMA site about Virtual MIDI. VM is an Apple thing. The MMA is solely concerned with physical devices and 5-pin DIN cables and what is signaled between the devices over those cables. You won't even find out much about MIDI itself either unless they've changed - they charge for the MIDI spec document. It's not available for free download there.
Note that MMA stands for MIDI Manufacturers Association. Emphasis on the middle word. But there are plenty of other sites (Google for them) that have the main parts of the specification posted.
The MMA have no say on how iOS devices use or tell us how they use MIDI. They only have legal control over the use of the IDI name and logo on things that have 5 pin DIN connectors on them. Strictly speaking that would apply to MIDI cable to USB interfaces but I believe that because of the translation to USB and the fact there is no driver software tied to them they can't enforce it.
The iOS world is not really required to follow MMA rules precisely because it is a virtual world. And as a result many Apps use it incorrectly and/or do not document fully (or at all) how they use it. The underlying iOS implementation of MIDI is likewise overly complicated and again not all MIDI implementations got that right. You can tell the ones that do - they work as expected with MidiBridge. Some that got it kinda wrong can be coaxed into working with MidiBridge. Some just flat out get in everybody's way. It's mainly only an issue if you want to use more than one MIDI synth at the same time and need routing between them and multiple sources.
Great insight @dwarman. I appreciate that!