I’m new and not an apple user trying to find a cheap way to make this thing mobile. What’sthe lowest version Iphone that Will work? Will an iphone 4 work?
Depends on the system, but if you’re on iOS 5 or upwards you should be able to play sounds on the iPhone; you wouldn’t be able to run the Artiphon app (which needs iOS 9 or later, and I think the iPhone 4 only goes up to iOS 7), but you can always do your preset editing on desktop. I have an original iPad 1 on 5.1.1 which happily runs old versions of Cubasis, SampleTank, ThumbJam, the iFretless and Crudebyte apps, Animoog, Thor, Sunrizer, and Magellan, among others; you connect the Artiphon with the USB cable through an old-style Apple CCK USB adapter, and it sounds great. Of course you’d need a newer device to purchase apps you don’t already own; you can only actually buy the current versions, but once it’s in your purchase history you can download compatible older versions (where available) on older devices.
iOS 4, on the other hand, is probably not worth struggling with getting MIDI to work on; it used to be possible with external kit like the Line6 Midi Mobilizer, but even that only did 5-pin DIN MIDI.
Let me just throw in here that there are lots of synths, DAWs, etc that only work on the iPad or where the interface is much better on the iPad. And Nick importantly pointed out that you can’t purchase new apps using a device that won’t support them, even if there’s an older version of the app floating around. So another option is to find an old iPad 2. It can run the current iOS but not the one coming out later this year.