How to connect my iPad Air and my Yamaha CP4 Stage Piano?

Question

Let's say I have Garageband for the iPad (or other Synths and Apps) and want to play them through my Digital Stage Piano which has a USB Host Adapter. (meaning it behaves like a SoundCard and connected to a MacBook it works out of the box).

What Kind of Cable/Adapter do I need?

Answer 1

If I'm understanding correctly, you want to use your keyboard as a midi controller.

Here is one example of an iPad midi interface that should do the trick:

http://www.amazon.com/gp/aw/d/B006L9FTMI/ref=mp_s_a_1_1?qid=1417364974&sr=8-1&pi=AC_SY200_QL40