Hi James,
We have to be precise here: you say Handheld Itouch and iPad, do you mean the 'music' app on those? Because those handhelds don;t play your locally stored library, but music stored on those handhelds, and of course all your Icloud music.
The itunes app on those is in fact the iTunes store, so not the same as your itunes-app on your mac either. Has all your bought recordings, but that's it.
If you want to control your iTunes library that is on your Mac/Windows machine or a shared Nas, you have to use the wonderful Remote-app and enable home sharing, or use the somewhat basic separate Apple remote, with which you can use the right/left keys to browse albums/artists and up/down for volume control. Play/pause are obvious.
Audirvana +, and I believe all the others that use iTunes (but not sure on this one) use the stored library, as is designated in the settings/advanced page.
Hope this helps.
Marius
The Handheld iTouch and the iPad.
I will look at home sharing but it was working OK before I loaded Audirvana?
james