I'd like to build a synthesizer for the iPhone. I understand that it's possible to use custom audio units for the iPhone. At first glance, this sounds promising, since there's lots and lots of Audio Unit programming resources available. However, using custom audio units on the iPhone seems a bit tricky ( see: http://lists.apple.com/archives/Coreaudio-api/2008/Nov/msg00262.html)
This seems like the sort of thing that loads of people must be doing, but a simple google search for "iphone audio synthesis" doesn't turn up anything along the lines of a nice and easy tutorial or recommended tool kit.
So, anyone here have experience synthesizing sound on the iPhone? Are custom audio units the way to go, or is there another, simpler approach I should consider?