Thanks to Daniel Davis and Saxifraga for helping me realise that you can use your iPhone as a midi junction box with ios7. They contacted me after reading about my experiences with the wonderful OP-1.
What I have been doing tonight thanks to them is playing my teenage engineering OP-1 via my CME Xkey. The big deal is both units, although they respond to midi, only have USB ports on them and not the usual midi sockets. Previously the only way you could connect one USB midi device to another was if you were attached to a computer. The cool thing about both the OP -1 and the Xkey is that they are both pretty small and entirely portable. I had been seeking a way to achieve this without nessicatating the hassle of a laptop around for what should be a sitting on a couch/train/aeroplane kind of thing. Using an app called MIDIbridge on my iPhone I have been able to achieve this. I have a USB hub with the two midi devices attached, then it’s plugged into my phone using a CCK (camera connection kit). Only with advent of the recent ios7 have iPhones been able to use the CCK. See my blog.
Gaz Williams 
Right on! Glad it worked for you. Now we just need to find a class-compliant, battery powered USB hub.
It’s pretty funny how we’re using these super high-tech devices as ways to transmit such an archaic form of data. 🙂
Haha been scouring the net for one! funny thing is though and I plan to update my blog to reflect this that if I plug things in a particular order they work with an non powered hub. All is fine for a while and then inexplicably the OP-1 encoders stop working. If you find a suitable hub, can you let me know please?
You would think that Apple would make one, and then charge $100 for it, because they know suckers like us would buy it. Seriously though, it would be a fantastic thing to have for a great mobile rig.
What’s the best portable key-controller you’ve used? I’m still using my Akai LPK25, but it doesn’t have MOD/Pitch wheels, which is a bummer.
I also have a QuNexus, but I don’t like it at all – it’s way too fiddly.
Dammit, now you’ve gotten me interested in the OP-1 again…
BTW, (and related to the comment above) what do you think of the build quality of the CME XKey? I like it because of it’s low profile, but do you think it can stand up to being tossed around in a backpack?
Whoops! OP1 is one of those things that I think you wouldn’t regret as it’s so unique. I can imagine myself using it 20 years from now!
Build quality on the CME Xkey is very good I would say and it could definitely survive backpack tossage. The more I use mine the more I like it. At first I wasn’t so keen but now I think it is an excellent bit of kit.
Hehe! Stop feeding the GAS! 😉
Great about the XKey! I’ve been using an LPK25 for a while but the quality and they key ‘action’ (if you can even call it that) are just horrible. I think I’ve been relatively easy on it but some of the keys are already giving up on me…
The Xkey does not have traditional keys but more like buttons not entirely dissimilar to the OP-1’s but they are velocity sensitive and of course transmits polyphonic after touch. The keys have a fair bit of travel in them considering its thickness though and once you get used to them are very playable. They are almost full size too just a bit shorter.
Very cool! Sorry for all the questions but what do you think about the ergonomics and playability of the PitchBend buttons?
Hmmm not so great but they are okay. They are, like the mod button too, pressure sensitive. I have heard that there may be a latching sustain mode soon.
That would be interesting. What’s the firmware / software update cycle like? Frequent?
Early days but they seem quite committed to it. There is an iPad app that lets you tweak various settings too.
Cool, so you wont even need a computer to tweak things like response curves and such? That is brilliant!
I’m reading conflicting reports on whether ios7 iphones 4s can do midi without an irig… I got a camera connector kit, was hoping to use midi > usb to connect but my midi controller isn’t generic, and doesn’t accept midi input…
i havent even mastered midi msgs yet, let alone CCs and OSC etc, but I’d love to know if I can load ‘pre-maps’ on-th-fly, to facilitate my psr170, in the absence of any dedicated kit (or budget!)
If I had a mac I imagine Siri would do it for me.
windows 7 (reaper!!!) and ios 7 (iphones 4s) – any options?
Can’t help there sorry only have a 5S now but my iPhone 5 worked well on iOS7. I think that things have improved further with iOS8 regarding midi. I guess try it and see.